# Chemical Survey toward Young Stellar Objects in the Perseus Molecular Cloud Complex

Aya E. Higuchi, Nami Sakai, Yoshimasa Watanabe, Ana López-Sepulcre, Kento Yoshida, Yoko Oya, Muneaki Imai, Yichen Zhang, Cecilia Ceccarelli, Bertrand Lefloch, et al.

► To cite this version:

Aya E. Higuchi, Nami Sakai, Yoshimasa Watanabe, Ana López-Sepulcre, Kento Yoshida, et al., Chemical Survey toward Young Stellar Objects in the Perseus Molecular Cloud Complex. The Astrophysical Journal Supplement Series, 2018, 236, 10.3847/1538-4365/aabfe9, insu-03693553

HAL Id: insu-03693553

https://insu.hal.science/insu-03693553v1

Submitted on 12 Jun 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
<figure><img src="image_2.png" /></figure>

# Chemical Survey toward Young Stellar Objects in the Perseus Molecular Cloud Complex

Aya E. Higuchi<fnref n="1" /> ID, Nami Sakai<fnref n="1" /> ID, Yoshimasa Watanabe<fnref n="2" /> ID, Ana López-Sepulcre<fnref n="3" />,<fnref n="4" />, Kento Yoshida<fnref n="1" />,<fnref n="5" />, Yoko Oya<fnref n="5" /> ID, Muneaki Imai<fnref n="5" /> ID, Yichen Zhang<fnref n="1" /> ID, Cecilia Ceccarelli<fnref n="3" /> ID, Bertrand Lefloch<fnref n="3" />, Claudio Codella<fnref n="6" /> ID, Rafael Bachiller<fnref n="7" /> ID, Tomoya Hirota<fnref n="8" /> ID, Takeshi Sakai<fnref n="9" /> ID, and Satoshi Yamamoto<fnref n="5" />

Received 2017 December 1; revised 2018 April 20; accepted 2018 April 21; published 2018 June 20

## Abstract

The chemical diversity of gas in low-mass protostellar cores is widely recognized. In order to explore the origin of this diversity, a survey of chemical composition toward 36 Class 0/I protostars in the Perseus molecular cloud complex, which are selected in an unbiased way under certain physical conditions, has been conducted with IRAM 30 m and NRO 45 m telescope. Multiple lines of C₂H, c-C₃H₂, and CH₃OH have been observed to characterize the chemical composition averaged over a 1000 au scale around the protostar. The derived beam-averaged column densities show significant chemical diversity among the sources, where the column density ratios of C₂H/CH₃OH are spread out by two orders of magnitude. From previous studies, the hot corino sources have abundant CH₃OH but deficient C₂H, their C₂H/CH₃OH column density ratios being relatively low. In contrast, the warm-carbon-chain chemistry (WCCC) sources are found to reveal the high C₂H/CH₃OH column density ratios. We find that the majority of the sources have intermediate characters between these two distinct chemistry types. A possible trend is seen between the C₂H/CH₃OH ratio and the distance of the source from the edge of a molecular cloud. The sources located near cloud edges or in isolated clouds tend to have a high C₂H/CH₃OH ratio. On the other hand, the sources having a low C₂H/CH₃OH ratio tend to be located in the inner regions of the molecular cloud complex. This result gives an important clue toward understanding the origin of the chemical diversity of protostellar cores in terms of environmental effects.

**Key words:** astrochemistry – ISM: molecules – stars: formation – stars: low-mass

**Supporting material:** extended figures

## 1. Introduction

The chemical compositions of protostellar cores are of fundamental importance because they are related to the initial condition for chemical evolution toward protoplanetary disks. During the last decade, they have extensively been studied by radioastronomical observations. Now, it is well known that the chemical compositions of low-mass protostellar cores ($r < \sim 1000$ au) show significant diversity (Sakai & Yamamoto 2013). One distinct case of diversity is hot corino chemistry. It is characterized by rich complex-organic molecules (COMs) such as HCOOCH₃ and (CH₃)₂O, and deficient carbon-chain molecules such as C₂H, c-C₃H₂ and C₄H. A prototypical hot corino source is IRAS 16293-2422 (e.g., Cazaux et al. 2003; Bottinelli et al. 2004). Another distinct case is warm-carbon-chain chemistry (WCCC). It is characterized by abundant carbon-chain molecules and deficient COMs. A prototypical WCCC source is IRAS 04368+2557 in L1527 (Sakai et al.

2008). This kind of exclusive chemical feature between COMs and carbon-chain molecules represents a major axis of chemical diversity. It should be noted that we do not know at this moment whether any other axes exist. In this paper, we therefore use the word “chemical diversity” to represent the hot corino chemistry versus WCCC axis.

Sakai et al. (2009) proposed that one possible origin of the above chemical diversity of low-mass protostellar cores is the difference of the duration time of their starless phase after the shielding of the interstellar UV radiation. After the UV-shielding, the formation of molecules starts both in the gas-phase and on dust grains, whose timescale is comparable to the dynamical timescale of a parent cloud (i.e., free-fall time). A longer duration for the starless phase tends to result in hot corino chemistry, while a shorter duration time results in WCCC. This mechanism can explain the various observational results obtained so far (Sakai & Yamamoto 2013). For instance, lower deuterium fractionation ratios and association of young starless cores near the WCCC source are consistent with this picture (Sakai et al. 2010; Sakai & Yamamoto 2013). However, other mechanisms such as shocks (outflows, cloud–cloud/filament–filament collision) and UV radiation from nearby OB stars may also contribute to chemical diversity (e.g., Buckle & Fuller 2002; Higuchi et al. 2010, 2014;

<figure><img src="image_3.png" /></figure>

Original content from this work may be used under the terms of the [Creative Commons Attribution 3.0 licence](https://creativecommons.org/licenses/by/3.0/). Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

<footnote n="1">¹ RIKEN Cluster for Pioneering Research, 2-1, Hirosawa, Wako-shi, Saitama 351-0198, Japan; aya.higuchi@riken.jp</footnote>

<footnote n="2">² Division of Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan</footnote>

<footnote n="3">³ Univ. Grenoble Alpes, CNRS, Institut de Plan étologie et d'Astrophysique de Grenoble (IPAG), F-38000 Grenoble, France</footnote>

<footnote n="4">⁴ Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, Domaine Universitaire de Grenoble, F-38406 Saint-Martin d'Hères, France</footnote>

<footnote n="5">⁵ Department of Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan</footnote>

<footnote n="6">⁶ INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125, Firenze, Italy</footnote>

<footnote n="7">⁷ IGN Observatorio Astronómico Nacional, Apartado 1143, E-28800 Alcalá de Henares, Spain</footnote>

<footnote n="8">⁸ National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588, Japan</footnote>

<footnote n="9">⁹ Department of Communication Engineering and Informatics, Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofugaoka, Chofu, Tokyo 182-8585, Japan</footnote>
Lindberg & Jørgensen 2012; Watanabe et al. 2012; Fukui et al. 2015; Spezzano et al. 2016a, 2016b). Hence, the origin of the above chemical diversity is still controversial.

So far, only a few sources have unambiguously been identified as hot corino sources and WCCC sources each. Examples of the former are IRAS 16293-2422, NGC 1333 IRAS 4A, NGC 1333 IRAS 4B, NGC 1333 IRAS 2, Serpens SMM1, Serpens SMM4, and HH212 (e.g., Cazaux et al. 2003; Bottinelli et al. 2004; Sakai et al. 2006; Öberg et al. 2011; Codella et al. 2016). Examples of the latter are L1527, IRAS 15398-3359, and TMC-1A (e.g., Sakai et al. 2008, 2014a). Thus, the statistics is very poor. To improve our understanding of the origin of the chemical diversity of protostellar cores, we need to know what kind of chemistry is commonly occurs. Recently, Lindberg et al. (2016) and Graninger et al. (2016) reported statistical studies of the CH$_3$OH and C$_4$H abundances toward low-mass star-forming cores. They used CH$_3$OH and C$_4$H as representative COM and carbon-chain molecules, respectively. Although these studies provide us with rich information on chemical diversity, different distances to the sources, as well as regional differences in physical conditions (UV radiation field, star formation activities) may complicate an interpretation of the observed chemical diversity.

A powerful approach to overcoming this situation is an unbiased survey of all protostellar cores in a single molecular cloud complex. Such a study would allow us to explore environmental effects on the chemical composition of protostellar sources in the molecular cloud complex without any preconception. In addition, all the targets are at almost the same distance, and are therefore affected similarly by beam dilution effects. This feature makes statistical arguments easier. With these in mind, we have conducted an unbiased chemical survey of the Perseus molecular cloud complex in the 3 and 1.3 mm bands. We observed the CH$_3$OH lines as a proxy of the COMs, because CH$_3$OH is a parent molecule for the production of larger COMs. We employed the C$_2$H and c-C$_3$H$_2$ lines as a proxy of carbon-chain-related molecules, because they are the most fundamental carbon-chain molecules giving bright emission. By comparing the results for these molecules, we discuss the chemical diversity of protostellar cores in Perseus.

## 2. Observations

### 2.1. Observed Sources and Molecules

The Perseus molecular cloud complex is one of the most famous and well-studied nearby low-mass star-forming regions (e.g., Hatchell et al. 2005; Jørgensen et al. 2006). The distance from the Sun is reported to be 235–238 pc (Hirota et al. 2008, 2011). In this paper, we employ a distance of 235 pc. It consists of a few molecular clouds, including NGC 1333, L1455, L1448, IC 348, B1, and Barnard 5 (B5), which show different star formation activities. In the whole Perseus molecular cloud extending over a 10 pc scale, about 400 sources are identified as young stellar object candidates, among which more than 50 are thought to be Class 0 or Class I protostars (Hatchell et al. 2005). We selected the target sources from the list by Hatchell et al. (2007) under the following criteria. (1) The protostellar sources are in the Class 0/I stage. (2) The bolometric luminosity is higher than $1 L_\odot$ (except for B1-5; 0.7 $L_\odot$). (3) The envelope mass is higher than $1 M_\odot$ to ensure association of a substantial amount of molecular gas. In total, 36 protostellar sources are in our target-source list

<table><caption>**Table 1**
Source List</caption><thead><tr><th>IDs</th><th>Source Names</th><th>R.A.<br>(J2000)</th><th>Decl.<br>(J2000)</th></tr></thead><tbody><tr><td>NGC 1333-1</td><td>IRAS 4B</td><td>03:29:12.01</td><td>31:13:08.2</td></tr><tr><td>NGC 1333-2</td><td>IRAS 2A</td><td>03:28:55.57</td><td>31:14:37.1</td></tr><tr><td>NGC 1333-3</td><td>IRAS 6; SK-24</td><td>03:29:01.66</td><td>31:20:28.5</td></tr><tr><td>NGC 1333-4</td><td>IRAS 7; SK-20</td><td>03:29:10.72</td><td>31:18:20.5</td></tr><tr><td>NGC 1333-5</td><td>IRAS 4C; SK-5</td><td>03:29:13.62</td><td>31:13:57.9</td></tr><tr><td>NGC 1333-6</td><td>IRAS 1; SK-6</td><td>03:28:37.11</td><td>31:13:28.3</td></tr><tr><td>NGC 1333-7</td><td>HH7-11 MMS 1; SK-15</td><td>03:29:06.50</td><td>31:15:38.6</td></tr><tr><td>NGC 1333-8</td><td>HH7-11 MMS 6; SK-14</td><td>03:29:04.09</td><td>31:14:46.6</td></tr><tr><td>NGC 1333-9</td><td>SVS 3; SK-28</td><td>03:29:10.70</td><td>31:21:45.3</td></tr><tr><td>NGC 1333-10</td><td>SK-29</td><td>03:29:07.70</td><td>31:21:56.8</td></tr><tr><td>NGC 1333-11</td><td>SK-18</td><td>03:29:07.10</td><td>31:17:23.7</td></tr><tr><td>NGC 1333-12</td><td>SK-32</td><td>03:29:18.25</td><td>31:23:16.9</td></tr><tr><td>NGC 1333-13</td><td></td><td>03:29:19.70</td><td>31:23:56.0</td></tr><tr><td>NGC 1333-14</td><td>No SMM/MM source</td><td>03:28:56.20</td><td>31:19:12.5</td></tr><tr><td>NGC 1333-15</td><td>SK-22</td><td>03:29:15.30</td><td>31:20:31.2</td></tr><tr><td>NGC 1333-16</td><td>IRAS 4A</td><td>03:29:10.53</td><td>31:13:31.0</td></tr><tr><td>NGC 1333-17</td><td>SVS 13A</td><td>03:29:03.75</td><td>31:16:03.76</td></tr><tr><td>L1448-1</td><td>L1448 NW; IRS3C</td><td>03:25:35.66</td><td>30:45:34.2</td></tr><tr><td>L1448-2</td><td>L1448 NB; IRS3</td><td>03:25:36.33</td><td>30:45:14.8</td></tr><tr><td>L1448-3</td><td>L1448 MM</td><td>03:25:38.87</td><td>30:44:05.3</td></tr><tr><td>L1448-4</td><td>IRS2</td><td>03:25:22.38</td><td>30:45:13.3</td></tr><tr><td>L1448-5</td><td>IRS2E</td><td>03:25:25.90</td><td>30:45:02.7</td></tr><tr><td>IC 348-1</td><td>HH211</td><td>03:43:56.80</td><td>32:00:50.3</td></tr><tr><td>IC 348-2</td><td>IC 348 MMS</td><td>03:43:57.05</td><td>32:03:05.0</td></tr><tr><td>IC 348-3</td><td></td><td>03:44:43.32</td><td>32:01:31.6</td></tr><tr><td>IC 348-4</td><td></td><td>03:43:50.99</td><td>32:03:24.7</td></tr><tr><td>Barnard 5</td><td>IRS 1</td><td>03:47:41.61</td><td>32:51:43.9</td></tr><tr><td>B1-1</td><td>B1-c</td><td>03:33:17.87</td><td>31:09:32.3</td></tr><tr><td>B1-2</td><td>B1-d</td><td>03:33:16.49</td><td>31:06:52.3</td></tr><tr><td>B1-3</td><td>B1-a</td><td>03:33:16.67</td><td>31:07:55.1</td></tr><tr><td>B1-4</td><td></td><td>03:32:18.03</td><td>30:49:46.9</td></tr><tr><td>B1-5</td><td></td><td>03:31:20.94</td><td>30:45:30.3</td></tr><tr><td>L1455-1</td><td>IRAS 03235+3004</td><td>03:26:37.46</td><td>30:15:28.2</td></tr><tr><td>L1455-2</td><td>IRS1; RNO 15 FIR; IRAS<br>03245+3002</td><td>03:27:39.11</td><td>30:13:02.8</td></tr><tr><td>L1455-3</td><td>IRS4</td><td>03:27:43.25</td><td>30:12:28.9</td></tr><tr><td>L1455-4</td><td>IRS2</td><td>03:27:47.69</td><td>30:12:04.4</td></tr></tbody></table>

Note. All sources are listed in Hatchell et al. (2005). A distance of 235 pc is adopted for all the sources.

(Table 1). Our sample is unbiased under the above three conditions. It should be stressed that it is unbiased from the viewpoint of chemical conditions.

We observed the CH$_3$OH, C$_2$H, and c-C$_3$H$_2$ lines listed in Table 2. CH$_3$OH is the most fundamental saturated organic molecule that is abundant in hot corino sources (e.g., Maret et al. 2005; Kristensen et al. 2010; Sakai et al. 2012). On the other hand, C$_2$H and c-C$_3$H$_2$ are basic carbon-chain-related molecules that are abundant in WCCC sources (e.g., Sakai et al. 2008, 2009). Hence, we can characterize the chemical composition of the sources with these species.

### 2.2. Observation with the Nobeyama 45 m Telescope

Observations of the CH$_3$OH lines in the 3 mm band were carried out with the 45 m telescope at the Nobeyama Radio Observatory (NRO) during 2014 January and 2015 March toward the target sources, except for NGC 1333-16 (IRAS 4A) and NGC 1333-17 (SVS 13A). These two sources were not observed due to the limited observation time. The side-band-separating (2SB) mixer receiver T100HV was used
<table><caption>**Table 2**
List of Observed Molecules</caption><thead><tr><th>Molecule</th><th>Transition</th><th>Frequency (GHz)</th><th>E<sub>u</sub> (K)</th><th>Sμ<sup>2</sup> (D<sup>2</sup>)</th></tr></thead><tbody><tr><td rowspan="4">C<sub>2</sub>H</td><td>N = 3–2, J = 5/2–3/2, F = 2–1</td><td>262.06746</td><td>25.2</td><td>1.1</td></tr><tr><td>N = 3–2, J = 5/2–3/2, F = 3–2</td><td>262.06498</td><td>25.2</td><td>1.6</td></tr><tr><td>N = 3–2, J = 7/2–5/2, F = 3–2</td><td>262.00648</td><td>25.1</td><td>1.7</td></tr><tr><td>N = 3–2, J = 7/2–5/2, F = 4–3</td><td>262.00426</td><td>25.2</td><td>2.3</td></tr><tr><td rowspan="12">CH<sub>3</sub>OH</td><td>J = 5–4, K = 2 E<sup>−</sup></td><td>241.90415</td><td>60.8</td><td>3.4</td></tr><tr><td>J = 5–4, K = 2 A<sup>+</sup></td><td>241.88770</td><td>72.6</td><td>3.4</td></tr><tr><td>J = 5–4, K = 1 E<sup>+</sup></td><td>241.87907</td><td>55.9</td><td>4.0</td></tr><tr><td>J = 5–4, K = 3 E<sup>−</sup></td><td>241.85235</td><td>97.6</td><td>2.6</td></tr><tr><td>J = 5–4, K = 2 A<sup>+</sup></td><td>241.84232</td><td>72.5</td><td>3.4</td></tr><tr><td>J = 5–4, K = 3 A<sup>±</sup></td><td>241.83291</td><td>84.7</td><td>2.6</td></tr><tr><td>J = 5–4, K = 4 E<sup>+</sup></td><td>241.82964</td><td>130.8</td><td>1.5</td></tr><tr><td>J = 5–4, K = 4 E<sup>−</sup></td><td>241.81325</td><td>122.7</td><td>1.4</td></tr><tr><td>J = 5–4, K = 4 A<sup>±</sup></td><td>241.80650</td><td>115.2</td><td>1.5</td></tr><tr><td>J = 5–4, K = 0 A<sup>+</sup></td><td>241.79143</td><td>34.8</td><td>4.0</td></tr><tr><td>J = 5–4, K = 1 E<sup>−</sup></td><td>241.76722</td><td>40.4</td><td>3.9</td></tr><tr><td>J = 5–4, K = 0 E<sup>+</sup></td><td>241.70021</td><td>47.9</td><td>4.0</td></tr><tr><td rowspan="3">CH<sub>3</sub>OH</td><td>J = 2–1, K = 0 E<sup>+</sup></td><td>96.74455</td><td>20.1</td><td>1.6</td></tr><tr><td>J = 2–1, K = 0 A<sup>+</sup></td><td>96.74137</td><td>7.0</td><td>1.6</td></tr><tr><td>J = 2–1, K = 1 E<sup>−</sup></td><td>96.73936</td><td>12.5</td><td>1.2</td></tr><tr><td>c-C<sub>3</sub>H<sub>2</sub></td><td>3<sub>2,1</sub>–2<sub>1,2</sub> (ortho)</td><td>244.22216</td><td>18.2</td><td>7.3</td></tr></tbody></table>

as the front end, with the typical system noise temperature ranging from 150 to 200 K. The beam size (HPBW) is 21" at 90 GHz, which corresponds to 4900 au at a distance of 235 pc. The back-end was a bank of 16 SAM-45 auto-correlators, whose bandwidth and frequency resolution each are 250 MHz and 122 kHz (with a velocity resolution of ~0.4 km s⁻¹), respectively.

The telescope pointing was checked every hour by observing the SiO maser source, NML Tau. The pointing accuracy was confirmed to be better than 7". The position switching mode was employed for all the above sources, where the position with the C¹⁸O integrated intensity lower than 1 K km s⁻¹ (Hatchell et al. 2005) near each target molecular cloud is taken as the off-position. The offset of the off-position relative to the target-source position is (δR.A., δdecl.) = (−1200′, 0″) for the sources in the NGC 1333 region, (−600″, 0″) for the sources in the L1448 region, (−600″, 0″) for the sources in the IC 348 and the Barnard 5 regions, (−850″, 0″) for the sources in the B1 region, and (0″, 780″) for the sources in the L1455 region. The intensity scale was calibrated to the antenna temperature (T*<sub>A</sub>) scale using the chopper-wheel method. The antenna temperature was converted to the main-beam brightness temperature using the main-beam efficiency of 0.45 provided by the observatory. The uncertainty of the intensity calibration is estimated to be better than 20%. The observed data were reduced with the software package NEWSTAR developed at NRO.

## 2.3. Observation with the IRAM 30 m Telescope

Observations of the CH<sub>3</sub>OH, C<sub>2</sub>H, and c-C<sub>3</sub>H<sub>2</sub> lines in the 1.3 mm band were carried out with the Institut de Radio Astronomie Millimétrique (IRAM) 30 m telescope at Pico Veleta. The sources, except for NGC 1333-16 (IRAS 4A) and NGC 1333-17 (SVS 13A), were observed in the period from between 2015 January to 2016 May. For these two sources, we use the data taken by the ASAI (Astrochemical Survey At IRAM) project (Lefloch et al. 2018). The Eight Mixer Receiver

(EMIR), E230, was employed in the dual-polarization mode. The system temperatures ranged from 250 to 400 K. HPBW is 10" at 260 GHz, which corresponds to 2400 au at a distance of 235 pc. The back-end consists of eight Fourier transform spectrometers (FTS), whose bandwidth and channel width each are 400 MHz and 200 kHz (with a velocity resolution of ~0.3 km s⁻¹), respectively. The telescope pointing was checked every hour by observing nearby continuum sources and was confirmed to be better than ~5". The position switching mode was employed for all the above sources. As for the off-position, we used the same position used for the Nobeyama observations, while the wobbler switching mode was employed for NGC 1333-16 and NGC 1333-17.<fnref n="10" /> The intensity scale was calibrated to the antenna temperature scale using the two temperature loads. T*<sub>A</sub> was then converted to the main-beam temperature T<sub>MB</sub> by multiplying F<sub>eff</sub>/B<sub>eff</sub> (mean value between 240 and 260 GHz), where F<sub>eff</sub> is the forward efficiency (0.92) and B<sub>eff</sub> is the main-beam efficiency (0.59). The uncertainty of the intensity calibration is estimated to be better than 20%. The data were reduced with the CLASS software of the GILDAS package.

# 3. Results

## 3.1. Data Analyses

Figure 1 shows the observed spectral lines of CH<sub>3</sub>OH (J = 5–4, K = 1, E<sup>−</sup>, E<sub>u</sub> = 40 K) and C<sub>2</sub>H (N = 3–2, J = 5/2–3/2, F = 3–2, E<sub>u</sub> = 25 K) for a few selected sources. The relative intensities between CH<sub>3</sub>OH and C<sub>2</sub>H are significantly different among the sources (see Table 3). For instance, the CH<sub>3</sub>OH line is strongly detected toward NGC 1333-1, whereas the intensity of the C<sub>2</sub>H line is weak. In contrast, NGC 1333-6 shows an opposite trend; CH<sub>3</sub>OH is not detected. A similar trend can be seen in B1-5: the C<sub>2</sub>H lines are strong, while the CH<sub>3</sub>OH lines are weak. For B1-3 and L1448-3, both the CH<sub>3</sub>OH and C<sub>2</sub>H lines are moderately intense. To quantify the trend, we evaluated the line parameters for each line by assuming that the line profile is approximated by a Gaussian function.

The CH<sub>3</sub>OH lines at 242 GHz would likely trace a relatively dense and warm region rather than a cold ambient cloud, because of their upper state energies (e.g., CH<sub>3</sub>OH; J = 5–4, K = 1, E<sup>−</sup>, E<sub>u</sub> = 40 K) and their critical densities (10<sup>5</sup>–6 cm<sup>−3</sup>). The CH<sub>3</sub>OH (J = 5–4) lines were detected toward 35 of the 36 sources. Their spectra are shown in Figure 2. Individual line parameters of CH<sub>3</sub>OH (J = 5–4) are listed in Table 4. For NGC 1333-1 (IRAS 4B), and NGC 1333-2 (IRAS 2), 9 and 12 K-structure lines of CH<sub>3</sub>OH were detected, respectively, as also reported in Maret et al. (2005). The CH<sub>3</sub>OH (J = 5–4) lines detected in L1448-5, B1-1, and B1-3 accompany strong wing components. On the other hand, the CH<sub>3</sub>OH (J = 2–1) lines (two or three K-structure) at 97 GHz were detected toward all the sources, whose line parameters are listed in Table 5.

The C<sub>2</sub>H (N = 3–2) lines at 262 GHz were detected toward all the sources, as shown in Figure 3. These lines also trace a relatively dense and warm region as in the case of the CH<sub>3</sub>OH line. Four hyperfine components were seen in all the sources. Their individual line parameters obtained with the Gaussian fit are listed in Table 9. The line parameters of the weakest

<footnote n="10">¹⁰ For IC 348-3, the C¹⁸O integrated intensity did not meet the above criteria. Since the systemic velocity of the off-position is shifted by ~1.5 km s⁻¹ from the systemic velocity of IC 348-3, the influence on the analysis in this study would be negligible.</footnote>
<figure><img src="image_4.png" /><figcaption>**Figure 1.** Line profiles of CH<sub>3</sub>OH (J = 5–4, K = 1, E<sup>-</sup>) and C<sub>2</sub>H (N = 3–2, J = 5/2–3/2) observed with IRAM 30 m toward NGC 1333-1, NGC 1333-6, B1-3, B1-5, and L1448-3. Two hyperfine components, F = 2–1 (left) and F = 3–2 (right), are observed.</figcaption></figure>

hyperfine component are missing for some sources, because the Gaussian fit was unsuccessful due to a poor S/N. For NGC 1333-1 and NGC 1333-16, the line shapes of the C<sub>2</sub>H lines are quite different from those of the other sources; i.e., the

intensities are weaker and the velocity widths are broader (dv ~ 2.6 km s<sup>-1</sup>) than in the other sources. The C<sub>2</sub>H emission toward NGC 1333-1 and NGC 1333-16 may be affected by the protostellar activities within the cores (e.g., molecular
<table><caption>**Table 3**

Physical Parameters</caption><thead><tr><th>IDs</th><th>T<sub>rot</sub><br>(K)</th><th>N(CH<sub>3</sub>OH)<br>(10<sup>14</sup> cm<sup>-2</sup>)</th><th>N(C<sub>2</sub>H)<br>(10<sup>13</sup> cm<sup>-2</sup>)</th><th>N(c-C<sub>3</sub>H<sub>2</sub>)<br>(10<sup>12</sup> cm<sup>-2</sup>)</th><th>N(C<sub>2</sub>H)/N(CH<sub>3</sub>OH)</th><th>N(c-C<sub>3</sub>H<sub>2</sub>)/N(CH<sub>3</sub>OH)</th></tr></thead><tbody><tr><td>NGC 1333-1</td><td>21 ± 2</td><td>5.2 ± 0.9</td><td>2.0 ± 0.3</td><td>4.5 ± 1.3</td><td>0.04 ± 0.01</td><td>0.009 ± 0.003</td></tr><tr><td>NGC 1333-2</td><td>19 ± 2</td><td>1.3 ± 0.4</td><td>4.1 ± 0.5</td><td>14 ± 3</td><td>0.32 ± 0.10</td><td>0.11 ± 0.04</td></tr><tr><td>NGC 1333-3</td><td>14 ± 1</td><td>1.2 ± 0.2</td><td>9.0 ± 1.1</td><td>5.4 ± 1.1</td><td>0.72 ± 0.11</td><td>0.04 ± 0.01</td></tr><tr><td>NGC 1333-4</td><td>12 ± 1</td><td>1.5 ± 0.2</td><td>4.1 ± 0.4</td><td>2.9 ± 1.0</td><td>0.27 ± 0.04</td><td>0.019 ± 0.007</td></tr><tr><td>NGC 1333-5</td><td>9 ± 1</td><td>1.9 ± 0.4</td><td>7.6 ± 0.8</td><td>6.0 ± 1.2</td><td>0.41 ± 0.06</td><td>0.032 ± 0.008</td></tr><tr><td>NGC 1333-6</td><td>9 ± 1</td><td>0.3 ± 0.1</td><td>11 ± 1</td><td>22 ± 3</td><td>3.9 ± 1.6</td><td>0.80 ± 0.34</td></tr><tr><td>NGC 1333-7</td><td>11 ± 1</td><td>3.0 ± 0.8</td><td>4.6 ± 0.7</td><td>6.0 ± 1.4</td><td>0.15 ± 0.03</td><td>0.020 ± 0.005</td></tr><tr><td>NGC 1333-8</td><td>10 ± 1</td><td>1.1 ± 0.4</td><td>7.1 ± 0.9</td><td>5.0 ± 1.4</td><td>0.66 ± 0.14</td><td>0.05 ± 0.02</td></tr><tr><td>NGC 1333-9</td><td>14 ± 3</td><td>0.2 ± 0.1</td><td>4.6 ± 1.2</td><td>&lt;1.9</td><td>2.1 ± 1.2</td><td>0.09 ± 0.05</td></tr><tr><td>NGC 1333-10</td><td>13 ± 2</td><td>0.2 ± 0.07</td><td>0.9 ± 0.3</td><td>&lt;1.9</td><td>0.50 ± 0.26</td><td>0.11 ± 0.05</td></tr><tr><td>NGC 1333-11</td><td>10 ± 1</td><td>0.9 ± 0.1</td><td>1.6 ± 0.3</td><td>2.1 ± 0.7</td><td>0.18 ± 0.04</td><td>0.024 ± 0.009</td></tr><tr><td>NGC 1333-12</td><td>10 ± 1</td><td>0.1 ± 0.04</td><td>0.8 ± 0.2</td><td>&lt;1.5</td><td>0.72 ± 0.37</td><td>0.14 ± 0.06</td></tr><tr><td>NGC 1333-13</td><td>14 ± 2</td><td>0.3 ± 0.07</td><td>0.8 ± 0.2</td><td>&lt;1.3</td><td>0.23 ± 0.07</td><td>0.039 ± 0.009</td></tr><tr><td>NGC 1333-14</td><td>11 ± 1</td><td>1.3 ± 0.1</td><td>1.7 ± 0.2</td><td>3.3 ± 0.8</td><td>0.14 ± 0.02</td><td>0.026 ± 0.007</td></tr><tr><td>NGC 1333-15</td><td>16 ± 2</td><td>0.8 ± 0.1</td><td>0.5 ± 0.2</td><td>&lt;1.5</td><td>0.07 ± 0.03</td><td>0.020 ± 0.005</td></tr><tr><td>NGC 1333-16</td><td>21<sup>a</sup></td><td>2.3 ± 0.5</td><td>1.8 ± 0.2</td><td>5.0 ± 0.6</td><td>0.08 ± 0.02</td><td>0.022 ± 0.005</td></tr><tr><td>NGC 1333-17</td><td>19<sup>b</sup></td><td>0.5 ± 0.1</td><td>7.4 ± 0.6</td><td>8.9 ± 0.8</td><td>1.7 ± 0.3</td><td>0.20 ± 0.04</td></tr><tr><td>L1448-1</td><td>9 ± 1</td><td>1.4 ± 0.3</td><td>12 ± 1</td><td>31 ± 4</td><td>0.84 ± 0.18</td><td>0.23 ± 0.05</td></tr><tr><td>L1448-2</td><td>13 ± 1</td><td>2.9 ± 0.3</td><td>16 ± 2</td><td>24 ± 3</td><td>0.57 ± 0.08</td><td>0.09 ± 0.01</td></tr><tr><td>L1448-3</td><td>14 ± 1</td><td>0.8 ± 0.2</td><td>4.6 ± 0.6</td><td>12 ± 2</td><td>0.60 ± 0.14</td><td>0.15 ± 0.04</td></tr><tr><td>L1448-4</td><td>10 ± 1</td><td>1.9 ± 0.2</td><td>12 ± 1</td><td>10 ± 1</td><td>0.64 ± 0.09</td><td>0.05 ± 0.01</td></tr><tr><td>L1448-5</td><td>10 ± 1</td><td>2.1 ± 0.2</td><td>2.1 ± 0.4</td><td>7.4 ± 1.2</td><td>0.10 ± 0.02</td><td>0.034 ± 0.007</td></tr><tr><td>IC 348-1</td><td>11 ± 1</td><td>1.3 ± 0.2</td><td>5.0 ± 0.5</td><td>11 ± 2</td><td>0.38 ± 0.06</td><td>0.08 ± 0.02</td></tr><tr><td>IC 348-2</td><td>12 ± 1</td><td>0.6 ± 0.1</td><td>7.0 ± 0.7</td><td>12 ± 2</td><td>1.2 ± 0.23</td><td>0.21 ± 0.04</td></tr><tr><td>IC 348-3</td><td>10 ± 1</td><td>0.3 ± 0.1</td><td>3.2 ± 0.6</td><td>&lt;1.6</td><td>0.96 ± 0.35</td><td>0.05 ± 0.02</td></tr><tr><td>IC 348-4</td><td>13 ± 1</td><td>0.6 ± 0.1</td><td>4.2 ± 0.5</td><td>6.7 ± 1.1</td><td>0.69 ± 0.13</td><td>0.11 ± 0.02</td></tr><tr><td>Barnard 5</td><td>10 ± 1</td><td>0.5 ± 0.1</td><td>9.0 ± 1.1</td><td>9.4 ± 1.9</td><td>1.9 ± 0.5</td><td>0.20 ± 0.06</td></tr><tr><td>B1-1</td><td>9 ± 1</td><td>0.8 ± 0.1</td><td>4.3 ± 0.5</td><td>14 ± 2</td><td>0.55 ± 0.12</td><td>0.18 ± 0.04</td></tr><tr><td>B1-2</td><td>9 ± 1</td><td>0.8 ± 0.1</td><td>7.3 ± 0.8</td><td>12 ± 2</td><td>0.96 ± 0.19</td><td>0.16 ± 0.03</td></tr><tr><td>B1-3</td><td>11 ± 1</td><td>4.2 ± 0.4</td><td>3.4 ± 0.4</td><td>5.9 ± 1.2</td><td>0.08 ± 0.01</td><td>0.014 ± 0.003</td></tr><tr><td>B1-4</td><td>9 ± 1</td><td>0.8 ± 0.2</td><td>8.3 ± 1.2</td><td>13 ± 2</td><td>1.1 ± 0.3</td><td>0.18 ± 0.05</td></tr><tr><td>B1-5</td><td>10 ± 1</td><td>0.4 ± 0.1</td><td>3.1 ± 0.5</td><td>5.2 ± 1.2</td><td>0.93 ± 0.34</td><td>0.16 ± 0.06</td></tr><tr><td>L1455-1</td><td>9 ± 1</td><td>&lt;0.2</td><td>6.0 ± 1.1</td><td>7.7 ± 1.6</td><td>3.1 ± 1.5</td><td>0.39 ± 0.20</td></tr><tr><td>L1455-2</td><td>14 ± 1</td><td>0.7 ± 0.1</td><td>5.4 ± 0.7</td><td>9.0 ± 1.7</td><td>0.74 ± 0.15</td><td>0.12 ± 0.03</td></tr><tr><td>L1455-3</td><td>8 ± 1</td><td>0.3 ± 0.1</td><td>6.4 ± 0.9</td><td>5.1 ± 1.2</td><td>2.0 ± 0.7</td><td>0.16 ± 0.07</td></tr><tr><td>L1455-4</td><td>9 ± 1</td><td>0.5 ± 0.1</td><td>3.5 ± 0.6</td><td>1.8 ± 0.8</td><td>0.78 ± 0.26</td><td>0.04 ± 0.02</td></tr><tr><td>Reference</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>L1527</td><td>8 ± 1</td><td>0.8 ± 0.1</td><td>33 ± 3</td><td>49 ± 3</td><td>4.1 ± 0.5</td><td>0.60 ± 0.07</td></tr></tbody></table>

Notes. Rotation temperatures are derived by the rotation diagram method from the CH<sub>3</sub>OH (J = 2–1) and CH<sub>3</sub>OH (J = 5–4) lines. Column densities are derived from the CH<sub>3</sub>OH (J = 5–4, K = 1, E<sup>-</sup>), C<sub>2</sub>H (N = 3–2, J = 5/2–3/2, F = 3–2), and c-C<sub>3</sub>H<sub>2</sub> (3<sub>2,1</sub>–2<sub>1,2</sub>) lines. Error bars are calculated for the rms noise and do not include calibration uncertainty (20%). As a reference, the column densities of L1527 are derived with the available IRAM 30 m/NRO 45 m data set.

<sup>a</sup> A rotation temperature of NGC 1333-1 is applied due to the lack of NRO data. The column density changes within 10% for the change in the assumed rotation temperature of ±5 K.

<sup>b</sup> A rotation temperature of NGC 1333-2 is applied due to the lack of NRO data. The column density changes within 10% for the change in the assumed rotation temperature of ±5 K.

outflows). For the other sources, the velocity widths of the C<sub>2</sub>H emission mostly range from 0.6 to 1.5 km s<sup>-1</sup>, indicating that the C<sub>2</sub>H emission would mainly originate from protostellar envelopes or cavity walls of low-velocity outflows, rather than the main bodies of molecular outflows (e.g., Oya et al. 2014; Sakai et al. 2014a).

The c-C<sub>3</sub>H<sub>2</sub> (3<sub>2,1</sub>–2<sub>1,2</sub>) line at 244 GHz was detected toward 30 sources, as shown in Figure 4. The line parameters obtained with the Gaussian fit are summarized in Table 7. For this line, the upper state energy is 18 K, and the critical density is 10<sup>6</sup> cm<sup>-3</sup>. Hence, this line traces a moderately dense region. c-C<sub>3</sub>H<sub>2</sub> is a carbon-chain related molecule, and traces the protostellar envelope as C<sub>2</sub>H (Sakai et al. 2010, 2014b;

Yoshida et al. 2015). The results show that the intensity of the 3<sub>2,1</sub>–2<sub>1,2</sub> line differs from source to source. The velocity widths of the c-C<sub>3</sub>H<sub>2</sub> line are similar to those of C<sub>2</sub>H. Therefore, the c-C<sub>3</sub>H<sub>2</sub> and C<sub>2</sub>H emission likely comes from almost the same region in each source.

## 3.2. Correlation of Integrated Intensities between C<sub>2</sub>H and CH<sub>3</sub>OH

A correlation plot between the integrated intensities of the C<sub>2</sub>H (N = 3–2, J = 5/2–3/2, F = 3–2, E<sub>u</sub> = 25 K) and CH<sub>3</sub>OH (J = 5–4, K = 1, E<sup>-</sup>, E<sub>u</sub> = 40 K) lines is then prepared to understand how the intensity ratios differ among the observed sources. We employ the third weakest hyperfine
<table><caption>**Table 4**
Line Parameters of the CH₃OH (J = 5–4) Lines Observed with IRAM 30 m</caption><thead><tr><th>IDs</th><th>Transition<br>J, K</th><th>T<sub>MB</sub><sup>a</sup><br>(K)</th><th>dv<sup>b</sup><br>(km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<sub>eff</sub><sup>c</sup><br>(K km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<sup>d</sup><br>(K km s<sup>-1</sup>)</th><th>rms<sup>e</sup><br>(K)</th><th>V<sub>LSR</sub><br>(km s<sup>-1</sup>)</th></tr></thead><tbody><tr><td rowspan="10">NGC 1333-1</td><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.98</td><td>3.23 (0.49)</td><td>2.45 (0.33)</td><td>5.04 (0.49)</td><td>0.13</td><td>6.6</td></tr><tr><td>J = 5-4, K = 2 A<sup>+</sup></td><td>0.22</td><td>2.53 (1.94)</td><td>0.54 (0.33)</td><td>0.85 (0.43)</td><td>0.13</td><td>6.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>+</sup></td><td>0.58</td><td>2.91 (0.81)</td><td>1.44 (0.33)</td><td>2.61 (0.47)</td><td>0.13</td><td>7.0</td></tr><tr><td>J = 5-4, K = 3 E<sup>-</sup></td><td>0.08</td><td>3.66 (6.23)<sup>f</sup></td><td>0.19 (0.33)<sup>f</sup></td><td>0.38 (0.45)<sup>f</sup></td><td>0.13</td><td>7.1</td></tr><tr><td>J = 5-4, K = 2 A<sup>-</sup></td><td>0.27</td><td>4.40 (2.32)<sup>f</sup></td><td>0.67 (0.33)<sup>f</sup></td><td>1.65 (0.59)<sup>f</sup></td><td>0.13</td><td>6.2</td></tr><tr><td>J = 5-4, K = 3 A<sup>±</sup></td><td>0.34</td><td>3.98 (0.84)</td><td>0.87 (0.33)</td><td>2.18 (0.08)</td><td>0.13</td><td>5.8</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>2.20</td><td>2.87 (0.10)</td><td>5.41 (0.33)</td><td>10.4 (0.08)</td><td>0.13</td><td>6.7</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>1.94</td><td>2.82 (0.11)</td><td>4.84 (0.33)</td><td>8.56 (0.08)</td><td>0.13</td><td>6.8</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.94</td><td>3.68 (0.31)</td><td>2.38 (0.33)</td><td>4.89 (0.08)</td><td>0.13</td><td>6.9</td></tr><tr><td rowspan="10">NGC 1333-2</td><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.49</td><td>3.05 (0.44)</td><td>0.67 (0.20)</td><td>2.24 (0.22)</td><td>0.15</td><td>6.5</td></tr><tr><td>J = 5-4, K = 2 A<sup>+</sup></td><td>0.27</td><td>2.79 (0.70)</td><td>0.37 (0.20)</td><td>1.08 (0.21)</td><td>0.15</td><td>5.9</td></tr><tr><td>J = 5-4, K = 1 E<sup>+</sup></td><td>0.34</td><td>2.95 (0.62)</td><td>0.47 (0.20)</td><td>1.47 (0.22)</td><td>0.15</td><td>6.8</td></tr><tr><td>J = 5-4, K = 3 E<sup>-</sup></td><td>0.23</td><td>2.54 (0.65)</td><td>0.32 (0.20)</td><td>0.79 (0.19)</td><td>0.15</td><td>6.2</td></tr><tr><td>J = 5-4, K = 2 A<sup>-</sup></td><td>0.30</td><td>3.51 (0.62)</td><td>0.42 (0.20)</td><td>1.47 (0.22)</td><td>0.15</td><td>5.6</td></tr><tr><td>J = 5-4, K = 3 A<sup>±</sup></td><td>0.31</td><td>2.71 (0.62)</td><td>0.43 (0.20)</td><td>1.14 (0.23)</td><td>0.15</td><td>5.5</td></tr><tr><td>J = 5-4, K = 4 E<sup>+</sup></td><td>0.18</td><td>2.02 (1.0)</td><td>0.25 (0.20)</td><td>0.60 (0.22)</td><td>0.15</td><td>6.1</td></tr><tr><td>J = 5-4, K = 4 E<sup>-</sup></td><td>0.19</td><td>2.58 (0.79)</td><td>0.26 (0.20)</td><td>0.67 (0.17)</td><td>0.15</td><td>6.4</td></tr><tr><td>J = 5-4, K = 4 A<sup>±</sup></td><td>0.22</td><td>2.48 (0.65)</td><td>0.30 (0.20)</td><td>0.75 (0.16)</td><td>0.15</td><td>6.0</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>1.02</td><td>2.68 (0.22)</td><td>1.41 (0.20)</td><td>4.53 (0.20)</td><td>0.15</td><td>7.3</td></tr><tr><td rowspan="10">NGC 1333-3</td><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.84</td><td>3.05 (0.28)</td><td>1.17 (0.20)</td><td>4.08 (0.23)</td><td>0.15</td><td>7.4</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.41</td><td>3.04 (0.53)</td><td>0.57 (0.20)</td><td>1.99 (0.21)</td><td>0.15</td><td>6.9</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.16</td><td>0.92 (0.11)</td><td>0.16 (0.03)</td><td>0.18 (0.02)</td><td>0.03</td><td>7.3</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>1.02</td><td>1.06 (0.02)</td><td>1.03 (0.03)</td><td>1.33 (0.02)</td><td>0.03</td><td>7.5</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.84</td><td>0.98 (0.03)</td><td>0.84 (0.03)</td><td>1.07 (0.02)</td><td>0.03</td><td>7.7</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.18</td><td>0.92 (0.13)</td><td>0.18 (0.03)</td><td>0.18 (0.02)</td><td>0.03</td><td>7.8</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.14</td><td>0.63 (0.12)</td><td>0.15 (0.03)</td><td>0.14 (0.02)</td><td>0.03</td><td>7.9</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.95</td><td>1.24 (0.02)</td><td>0.95 (0.03)</td><td>1.56 (0.02)</td><td>0.03</td><td>8.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.81</td><td>1.17 (0.03)</td><td>0.82 (0.03)</td><td>1.25 (0.02)</td><td>0.03</td><td>8.4</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.15</td><td>1.04 (0.18)</td><td>0.15 (0.03)</td><td>0.19 (0.02)</td><td>0.03</td><td>8.4</td></tr><tr><td rowspan="10">NGC 1333-4</td><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.68</td><td>0.76 (0.04)</td><td>0.67 (0.03)</td><td>0.69 (0.02)</td><td>0.03</td><td>7.5</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.61</td><td>0.72 (0.04)</td><td>0.60 (0.03)</td><td>0.65 (0.02)</td><td>0.03</td><td>7.6</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.14</td><td>0.62 (0.12)</td><td>0.14 (0.03)</td><td>0.21 (0.02)</td><td>0.03</td><td>7.6</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.11</td><td>1.82 (0.31)</td><td>0.09 (0.02)</td><td>0.24 (0.03)</td><td>0.03</td><td>6.8</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.10</td><td>2.27 (0.32)</td><td>0.09 (0.02)</td><td>0.23 (0.03)</td><td>0.03</td><td>7.2</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.04</td><td>4.00 (1.08)</td><td>0.03 (0.02)</td><td>0.17 (0.04)</td><td>0.03</td><td>7.0</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>1.13</td><td>1.24 (0.02)</td><td>1.75 (0.04)</td><td>1.86 (0.02)</td><td>0.03</td><td>7.3</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.87</td><td>1.28 (0.03)</td><td>1.35 (0.04)</td><td>1.51 (0.02)</td><td>0.03</td><td>7.4</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.11</td><td>1.52 (0.27)</td><td>0.17 (0.04)</td><td>0.22 (0.03)</td><td>0.03</td><td>7.3</td></tr><tr><td rowspan="10">NGC 1333-5</td><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.43</td><td>2.03 (0.07)</td><td>0.49 (0.03)</td><td>1.11 (0.03)</td><td>0.03</td><td>6.8</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.33</td><td>2.04 (0.10)</td><td>0.38 (0.03)</td><td>0.89 (0.03)</td><td>0.03</td><td>6.9</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.06</td><td>2.11 (0.42)</td><td>0.07 (0.03)</td><td>0.17 (0.03)</td><td>0.03</td><td>7.0</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.08</td><td>1.00 (0.68)</td><td>0.08 (0.04)</td><td>0.16 (0.04)</td><td>0.03</td><td>7.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.09</td><td>0.89 (0.16)</td><td>0.15 (0.04)</td><td>0.14 (0.02)</td><td>0.03</td><td>7.1</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.07</td><td>1.87 (0.26)</td><td>0.09 (0.03)</td><td>0.12 (0.02)</td><td>0.02</td><td>7.3</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.08</td><td>1.00 (0.18)</td><td>0.11 (0.03)</td><td>0.05 (0.01)</td><td>0.02</td><td>7.4</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.67</td><td>1.08 (0.02)</td><td>0.40 (0.01)</td><td>0.92 (0.01)</td><td>0.02</td><td>8.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.52</td><td>1.12 (0.03)</td><td>0.31 (0.01)</td><td>0.60 (0.02)</td><td>0.02</td><td>8.4</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.07</td><td>1.43 (0.22)</td><td>0.04 (0.01)</td><td>0.09 (0.02)</td><td>0.03</td><td>8.3</td></tr><tr><td rowspan="10">NGC 1333-6</td><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.10</td><td>0.48 (0.10)</td><td>0.06 (0.01)</td><td>0.04 (0.01)</td><td>0.02</td><td>7.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.09</td><td>0.77 (0.22)</td><td>0.04 (0.01)</td><td>0.07 (0.01)</td><td>0.02</td><td>7.4</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.50</td><td>0.69 (0.03)</td><td>0.28 (0.01)</td><td>0.43 (0.01)</td><td>0.02</td><td>7.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.43</td><td>0.69 (0.03)</td><td>0.24 (0.01)</td><td>0.43 (0.01)</td><td>0.02</td><td>7.3</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.09</td><td>0.94 (0.18)</td><td>0.07 (0.02)</td><td>0.06 (0.02)</td><td>0.02</td><td>7.1</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.91</td><td>1.17 (0.02)</td><td>0.80 (0.02)</td><td>1.27 (0.02)</td><td>0.02</td><td>7.6</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.70</td><td>1.20 (0.02)</td><td>0.61 (0.02)</td><td>0.99 (0.02)</td><td>0.02</td><td>7.7</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.12</td><td>1.17 (0.18)</td><td>0.10 (0.02)</td><td>0.18 (0.02)</td><td>0.02</td><td>7.8</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.81</td><td>0.72 (0.02)</td><td>0.70 (0.02)</td><td>0.76 (0.01)</td><td>0.02</td><td>7.8</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.67</td><td>0.68 (0.02)</td><td>0.58 (0.02)</td><td>0.61 (0.01)</td><td>0.02</td><td>8.0</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.07</td><td>1.15(0.31)</td><td>0.06 (0.02)</td><td>0.11 (0.02)</td><td>0.02</td><td>8.0</td></tr><tr><td rowspan="10">NGC 1333-7</td><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.36</td><td>4.91 (1.96)</td><td>0.77 (0.36)</td><td>2.23 (0.52)</td><td>0.11</td><td>6.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>+</sup></td><td>0.21</td><td>4.72 (3.29)</td><td>0.45 (0.36)</td><td>1.17 (0.53)</td><td>0.11</td><td>6.7</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.08</td><td>4.43 (7.02)<sup>f</sup></td><td>0.16 (0.36)<sup>f</sup></td><td>0.35 (0.46)<sup>f</sup></td><td>0.11</td><td>6.3</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.09</td><td>5.50 (6.57)<sup>f</sup></td><td>0.20 (0.36)<sup>f</sup></td><td>0.56 (0.50)<sup>f</sup></td><td>0.11</td><td>6.1</td></tr></tbody></table>
<table><caption>**Table 4**
(Continued)</caption><thead><tr><th>IDs</th><th>Transition<br>J, K</th><th>T<sub>MB</sub><sup>a</sup><br>(K)</th><th>dν<sup>b</sup><br>(km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dν<sub>eff</sub><sup>c</sup><br>(K km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dν<sup>d</sup><br>(K km s<sup>-1</sup>)</th><th>rms<sup>e</sup><br>(K)</th><th>V<sub>LSR</sub><br>(km s<sup>-1</sup>)</th></tr></thead><tbody><tr><td rowspan="12">NGC 1333-17</td><td>J = 5-4, K = 0 A<sup>+</sup></td><td>1.21</td><td>4.88 (0.72)</td><td>2.57 (0.36)</td><td>8.44 (0.59)</td><td>0.11</td><td>6.4</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>1.02</td><td>5.11 (0.78)</td><td>2.17 (0.36)</td><td>7.76 (0.71)</td><td>0.11</td><td>6.5</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.37</td><td>5.01 (0.78)</td><td>0.79 (0.36)</td><td>2.31 (0.61)</td><td>0.11</td><td>6.5</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.17</td><td>3.11 (0.39)</td><td>0.20 (0.05)</td><td>0.64 (0.22)</td><td>0.03</td><td>7.5</td></tr><tr><td>J = 5-4, K = 2 A<sup>+</sup></td><td>0.11</td><td>3.62 (0.55)</td><td>0.13 (0.05)</td><td>0.46 (0.21)</td><td>0.03</td><td>7.0</td></tr><tr><td>J = 5-4, K = 1 E<sup>+</sup></td><td>0.15</td><td>3.01 (0.39)</td><td>0.18 (0.05)</td><td>0.51 (0.22)</td><td>0.03</td><td>7.9</td></tr><tr><td>J = 5-4, K = 3 E<sup>-</sup></td><td>0.10</td><td>3.43 (0.61)</td><td>0.12 (0.05)</td><td>0.41 (0.19)</td><td>0.03</td><td>7.5</td></tr><tr><td>J = 5-4, K = 2 A<sup>-</sup></td><td>0.12</td><td>4.61 (0.57)</td><td>0.14 (0.05)</td><td>0.63 (0.22)</td><td>0.03</td><td>6.7</td></tr><tr><td>J = 5-4, K = 3 A<sup>±</sup></td><td>0.12</td><td>6.00 (0.55)</td><td>0.14 (0.05)</td><td>0.78 (0.23)</td><td>0.03</td><td>8.1</td></tr><tr><td>J = 5-4, K = 4 E<sup>+</sup></td><td>0.09</td><td>3.15 (0.50)</td><td>0.11 (0.05)</td><td>0.32 (0.17)</td><td>0.03</td><td>7.7</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.41</td><td>1.29 (0.08)</td><td>0.48 (0.05)</td><td>0.71 (0.20)</td><td>0.03</td><td>7.8</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.34</td><td>1.32 (0.10)</td><td>0.40 (0.05)</td><td>0.68 (0.23)</td><td>0.03</td><td>7.9</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.16</td><td>2.84 (0.50)</td><td>0.19 (0.05)</td><td>0.61 (0.21)</td><td>0.03</td><td>7.8</td></tr><tr><td rowspan="3">L1448-1</td><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.28</td><td>1.08 (0.12)</td><td>0.43 (0.05)</td><td>0.35 (0.01)</td><td>0.03</td><td>4.1</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.25</td><td>1.17 (0.11)</td><td>0.38 (0.05)</td><td>0.34 (0.01)</td><td>0.03</td><td>4.3</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.12</td><td>0.30 (0.10)</td><td>0.19 (0.05)</td><td>0.08 (0.01)</td><td>0.03</td><td>4.5</td></tr><tr><td rowspan="6">L1448-2</td><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.24</td><td>1.46 (0.15)</td><td>0.45 (0.05)</td><td>0.44 (0.02)</td><td>0.03</td><td>4.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>+</sup></td><td>0.16</td><td>1.14 (0.16)</td><td>0.30 (0.05)</td><td>0.29 (0.02)</td><td>0.03</td><td>4.7</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>1.15</td><td>1.28 (0.03)</td><td>2.16 (0.05)</td><td>2.22 (0.03)</td><td>0.03</td><td>4.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.94</td><td>1.21 (0.03)</td><td>1.76 (0.05)</td><td>1.46 (0.02)</td><td>0.03</td><td>4.3</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.34</td><td>1.33 (0.09)</td><td>0.63 (0.05)</td><td>0.54 (0.03)</td><td>0.03</td><td>4.5</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.16</td><td>2.65 (0.48)</td><td>0.17 (0.05)</td><td>0.67 (0.06)</td><td>0.05</td><td>4.6</td></tr><tr><td rowspan="6">L1448-3</td><td>J = 5-4, K = 1 E<sup>+</sup></td><td>0.13</td><td>1.30 (0.36)</td><td>0.14 (0.05)</td><td>0.27 (0.04)</td><td>0.05</td><td>5.0</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.58</td><td>1.18 (0.09)</td><td>0.63 (0.05)</td><td>1.04 (0.04)</td><td>0.05</td><td>4.6</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.48</td><td>1.14 (0.11)</td><td>0.52 (0.05)</td><td>0.99 (0.04)</td><td>0.05</td><td>4.8</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.24</td><td>1.16 (0.26)</td><td>0.26 (0.05)</td><td>0.56 (0.05)</td><td>0.05</td><td>4.9</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.10</td><td>1.21 (0.33)</td><td>0.10 (0.03)</td><td>0.21 (0.03)</td><td>0.03</td><td>3.3</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.82</td><td>0.72 (0.03)</td><td>0.82 (0.03)</td><td>0.78 (0.02)</td><td>0.03</td><td>3.7</td></tr><tr><td rowspan="6">L1448-4</td><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.71</td><td>0.68 (0.03)</td><td>0.71 (0.03)</td><td>0.69 (0.02)</td><td>0.03</td><td>3.9</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.09</td><td>1.38 (0.69)</td><td>0.09 (0.03)</td><td>0.13 (0.04)</td><td>0.03</td><td>3.8</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.06</td><td>3.27 (0.91)</td><td>0.05 (0.03)</td><td>0.19 (0.03)</td><td>0.04</td><td>3.6</td></tr><tr><td>J = 5-4, K = 1 E<sup>+</sup></td><td>0.12</td><td>0.56 (0.25)</td><td>0.08 (0.03)</td><td>0.04 (0.03)</td><td>0.04</td><td>4.1</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>1.32</td><td>0.97 (0.03)</td><td>0.87 (0.03)</td><td>2.37 (0.03)</td><td>0.04</td><td>3.8</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>1.20</td><td>0.86 (0.03)</td><td>0.80 (0.03)</td><td>1.89 (0.03)</td><td>0.04</td><td>3.9</td></tr><tr><td rowspan="3">IC 348-1</td><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.27</td><td>0.60 (0.13)</td><td>0.18 (0.03)</td><td>0.27 (0.03)</td><td>0.04</td><td>3.9</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.07</td><td>0.96 (0.40)</td><td>0.07 (0.03)</td><td>0.09 (0.02)</td><td>0.03</td><td>8.3</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.93</td><td>0.63 (0.02)</td><td>0.81 (0.03)</td><td>0.81 (0.02)</td><td>0.03</td><td>8.6</td></tr><tr><td rowspan="6">IC 348-2</td><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.76</td><td>0.62 (0.03)</td><td>0.65 (0.03)</td><td>0.74 (0.02)</td><td>0.03</td><td>8.7</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.13</td><td>1.04 (0.17)</td><td>0.10 (0.03)</td><td>0.13 (0.02)</td><td>0.03</td><td>8.8</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.07</td><td>1.59 (0.29)</td><td>0.07 (0.03)</td><td>0.12 (0.02)</td><td>0.03</td><td>8.2</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.36</td><td>0.80 (0.06)</td><td>0.40 (0.03)</td><td>0.37 (0.02)</td><td>0.02</td><td>8.4</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.28</td><td>0.74 (0.07)</td><td>0.31 (0.03)</td><td>0.32 (0.02)</td><td>0.02</td><td>8.5</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.06</td><td>1.29 (0.47)</td><td>0.07 (0.03)</td><td>0.10 (0.02)</td><td>0.03</td><td>8.5</td></tr><tr><td rowspan="3">IC 348-3</td><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.16</td><td>1.16 (0.10)</td><td>0.18 (0.03)</td><td>0.15 (0.02)</td><td>0.02</td><td>9.9</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.11</td><td>1.38 (0.16)</td><td>0.13 (0.03)</td><td>0.17 (0.02)</td><td>0.02</td><td>10</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.09</td><td>0.36 (0.11)</td><td>0.08 (0.02)</td><td>0.06 (0.01)</td><td>0.02</td><td>7.6</td></tr><tr><td rowspan="3">Barnard 5</td><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.46</td><td>0.76 (0.04)</td><td>0.40 (0.02)</td><td>0.52 (0.01)</td><td>0.02</td><td>8.0</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.41</td><td>0.69 (0.04)</td><td>0.36 (0.02)</td><td>0.46 (0.02)</td><td>0.02</td><td>8.2</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.26</td><td>0.80 (0.07)</td><td>0.22 (0.02)</td><td>0.26 (0.02)</td><td>0.02</td><td>9.6</td></tr><tr><td rowspan="6">B1-1</td><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.19</td><td>0.80 (0.08)</td><td>0.16 (0.02)</td><td>0.18 (0.02)</td><td>0.02</td><td>9.8</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.07</td><td>4.64 (0.24)</td><td>0.07 (0.03)</td><td>0.46 (0.09)</td><td>0.02</td><td>7.0</td></tr><tr><td>J = 5-4, K = 1 E<sup>+</sup></td><td>0.05</td><td>3.33(0.24)</td><td>0.06 (0.03)</td><td>0.20 (0.03)</td><td>0.02</td><td>6.5</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.25</td><td>4.52 (0.24)</td><td>0.39 (0.03)</td><td>1.75 (0.07)</td><td>0.02</td><td>6.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.21</td><td>4.54 (0.24)</td><td>0.23 (0.03)</td><td>1.47 (0.11)</td><td>0.02</td><td>6.9</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.08</td><td>2.66 (0.24)</td><td>0.08 (0.03)</td><td>0.21 (0.04)</td><td>0.02</td><td>6.5</td></tr><tr><td rowspan="3">B1-2</td><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.42</td><td>0.66 (0.04)</td><td>0.29 (0.02)</td><td>0.33 (0.01)</td><td>0.02</td><td>6.2</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.30</td><td>0.68 (0.05)</td><td>0.20 (0.02)</td><td>0.27 (0.01)</td><td>0.02</td><td>6.1</td></tr><tr><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.18</td><td>1.99 (0.22)</td><td>0.22 (0.05)</td><td>0.40 (0.04)</td><td>0.04</td><td>5.2</td></tr><tr><td rowspan="6">B1-3</td><td>J = 5-4, K = 1 E<sup>+</sup></td><td>0.10</td><td>1.89 (0.36)</td><td>0.12 (0.05)</td><td>0.20 (0.04)</td><td>0.04</td><td>5.7</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>1.96</td><td>1.45 (0.07)</td><td>2.50 (0.05)</td><td>3.99 (0.04)</td><td>0.04</td><td>5.8</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>1.65</td><td>1.37 (0.03)</td><td>2.10 (0.05)</td><td>3.16 (0.03)</td><td>0.04</td><td>5.9</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.26</td><td>2.31 (0.18)</td><td>0.33 (0.05)</td><td>0.66 (0.04)</td><td>0.04</td><td>5.6</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.29</td><td>0.78 (0.10)</td><td>0.31 (0.03)</td><td>0.33 (0.02)</td><td>0.03</td><td>6.5</td></tr></tbody></table>
<table><caption>**Table 4**
(Continued)</caption><thead><tr><th>IDs</th><th>Transition<br>J, K</th><th>T<sub>MB</sub><sup>a</sup><br>(K)</th><th>dv<sup>b</sup><br>(km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<sub>eff</sub><sup>c</sup><br>(K km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<sup>d</sup><br>(K km s<sup>-1</sup>)</th><th>rms<sup>e</sup><br>(K)</th><th>V<sub>LSR</sub><br>(km s<sup>-1</sup>)</th></tr></thead><tbody><tr><td rowspan="3">B1-5</td><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.21</td><td>0.71 (0.09)</td><td>0.22 (0.03)</td><td>0.18 (0.02)</td><td>0.03</td><td>6.5</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.17</td><td>0.49 (0.11)</td><td>0.16 (0.02)</td><td>0.16 (0.02)</td><td>0.03</td><td>5.6</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.12</td><td>0.82 (0.21)</td><td>0.11 (0.02)</td><td>0.11 (0.01)</td><td>0.03</td><td>6.6</td></tr><tr><td>L1455-1</td><td>...</td><td>...</td><td>...</td><td>0.05 (0.02)</td><td>0.06</td><td>0.02</td><td>...</td></tr><tr><td rowspan="4">L1455-2</td><td>J = 5-4, K = 2 E<sup>-</sup></td><td>0.09</td><td>4.65 (0.66)</td><td>0.11 (0.03)</td><td>0.59 (0.04)</td><td>0.03</td><td>4.1</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.47</td><td>1.38 (0.07)</td><td>0.57 (0.03)</td><td>0.89 (0.02)</td><td>0.03</td><td>4.4</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.40</td><td>1.26 (0.07)</td><td>0.49 (0.03)</td><td>0.92 (0.02)</td><td>0.03</td><td>4.6</td></tr><tr><td>J = 5-4, K = 0 E<sup>+</sup></td><td>0.07</td><td>5.97 (0.85)</td><td>0.08 (0.03)</td><td>0.44 (0.04)</td><td>0.03</td><td>4.1</td></tr><tr><td rowspan="3">L1455-3</td><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.20</td><td>0.87 (0.09)</td><td>0.16 (0.02)</td><td>0.18 (0.02)</td><td>0.02</td><td>4.4</td></tr><tr><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.10</td><td>1.69 (0.23)</td><td>0.08 (0.02)</td><td>0.15 (0.02)</td><td>0.02</td><td>4.7</td></tr><tr><td>J = 5-4, K = 0 A<sup>+</sup></td><td>0.14</td><td>1.06 (0.13)</td><td>0.16 (0.02)</td><td>0.16 (0.02)</td><td>0.02</td><td>4.7</td></tr><tr><td>L1455-4</td><td>J = 5-4, K = 1 E<sup>-</sup></td><td>0.12</td><td>0.78 (0.15)</td><td>0.14 (0.02)</td><td>0.12 (0.02)</td><td>0.02</td><td>4.8</td></tr></tbody></table>

**Notes.** The errors are $1\sigma$. The upper limit to the integrated intensity is calculated as $\int T_{MB} dv < 3\sigma \times \sqrt{(dv/dv_{res})}$ $dv_{res}$, where $dv$ is the assumed line width (0.8 km s$^{-1}$) and $dv_{res}$ is the velocity resolution per channel.

a Obtained by the Gaussian fit.

b The wing components are excluded in the Gaussian fit.

c Derived using the C$_2$H velocity width.

d The wing components are included when calculating the integrated intensity.

e The rms noise averaged over the line width.

f The error in the Gaussian fitting is large.

<table><caption>**Table 5**
Line Parameters of the CH$_3$OH (J = 2-1) Lines Observed with the Nobeyama 45 m Telescope</caption><thead><tr><th>IDs</th><th>Transition<br>J, K</th><th>T<sub>MB</sub><sup>a</sup><br>(K)</th><th>dv<sup>b</sup><br>(km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<sub>eff</sub><sup>c</sup><br>(K km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<sup>d</sup><br>(K km s<sup>-1</sup>)</th><th>rms<sup>e</sup><br>(K)</th><th>V<sub>LSR</sub><br>(km s<sup>-1</sup>)</th></tr></thead><tbody><tr><td rowspan="3">NGC 1333-1</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.40</td><td>2.16 (0.04)</td><td>3.50 (0.04)</td><td>3.53 (0.04)</td><td>0.02</td><td>7.7</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.97</td><td>2.15 (0.04)</td><td>4.92 (0.04)</td><td>5.94 (0.04)</td><td>0.02</td><td>7.5</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.47</td><td>2.56 (0.04)</td><td>1.18 (0.04)</td><td>1.73 (0.04)</td><td>0.02</td><td>6.8</td></tr><tr><td rowspan="3">NGC 1333-2</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.38</td><td>1.32 (0.02)</td><td>1.91 (0.02)</td><td>2.57 (0.02)</td><td>0.02</td><td>7.7</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.73</td><td>1.37 (0.02)</td><td>2.39 (0.02)</td><td>3.32 (0.02)</td><td>0.02</td><td>7.9</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.27</td><td>1.56 (0.02)</td><td>0.38 (0.02)</td><td>0.62 (0.02)</td><td>0.02</td><td>7.6</td></tr><tr><td rowspan="3">NGC 1333-3</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.82</td><td>1.21 (0.02)</td><td>0.82 (0.02)</td><td>1.15 (0.02)</td><td>0.02</td><td>7.8</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.27</td><td>1.14 (0.02)</td><td>1.27 (0.02)</td><td>1.69 (0.02)</td><td>0.02</td><td>7.9</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.22</td><td>1.13 (0.02)</td><td>0.22 (0.02)</td><td>0.23 (0.02)</td><td>0.02</td><td>7.9</td></tr><tr><td rowspan="3">NGC 1333-4</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.18</td><td>1.19 (0.02)</td><td>1.19 (0.02)</td><td>1.68 (0.02)</td><td>0.02</td><td>8.5</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.74</td><td>1.18 (0.02)</td><td>1.76 (0.02)</td><td>2.52 (0.02)</td><td>0.02</td><td>8.6</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.35</td><td>1.01 (0.02)</td><td>0.35 (0.02)</td><td>0.42 (0.02)</td><td>0.02</td><td>8.7</td></tr><tr><td rowspan="3">NGC 1333-5</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.54</td><td>0.98 (0.01)</td><td>1.52 (0.01)</td><td>1.83 (0.01)</td><td>0.01</td><td>7.7</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>2.03</td><td>1.04 (0.02)</td><td>2.00 (0.01)</td><td>2.45 (0.02)</td><td>0.01</td><td>7.9</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.32</td><td>0.92 (0.01)</td><td>0.31 (0.01)</td><td>0.38 (0.01)</td><td>0.01</td><td>7.9</td></tr><tr><td rowspan="3">NGC 1333-6</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.23</td><td>1.17 (0.02)</td><td>0.21 (0.01)</td><td>0.32 (0.02)</td><td>0.02</td><td>7.4</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.29</td><td>1.02 (0.02)</td><td>0.26 (0.01)</td><td>0.39 (0.02)</td><td>0.02</td><td>7.2</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>2.01</td><td>1.34 (0.02)</td><td>3.11 (0.02)</td><td>3.03 (0.02)</td><td>0.02</td><td>7.7</td></tr><tr><td rowspan="3">NGC 1333-7</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>2.64</td><td>1.42 (0.02)</td><td>4.08 (0.02)</td><td>4.31 (0.02)</td><td>0.02</td><td>7.5</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.38</td><td>1.32 (0.02)</td><td>0.58 (0.02)</td><td>0.58 (0.02)</td><td>0.02</td><td>7.6</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>1.02</td><td>1.61 (0.02)</td><td>1.17 (0.02)</td><td>1.89 (0.02)</td><td>0.02</td><td>7.4</td></tr><tr><td rowspan="3">NGC 1333-8</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.45</td><td>1.54 (0.02)</td><td>1.68 (0.02)</td><td>2.54 (0.02)</td><td>0.02</td><td>7.5</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.15</td><td>1.78 (0.03)</td><td>0.17 (0.02)</td><td>0.31 (0.03)</td><td>0.02</td><td>7.6</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.09</td><td>1.98 (0.03)</td><td>0.14 (0.03)</td><td>0.18 (0.03)</td><td>0.02</td><td>8.1</td></tr><tr><td rowspan="3">NGC 1333-9</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.11</td><td>1.92 (0.03)</td><td>0.18 (0.03)</td><td>0.19 (0.03)</td><td>0.02</td><td>7.2</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.09</td><td>1.91 (0.03)</td><td>0.12 (0.02)</td><td>0.20 (0.03)</td><td>0.02</td><td>8.1</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.12</td><td>2.36 (0.04)</td><td>0.16 (0.02)</td><td>0.25 (0.04)</td><td>0.02</td><td>7.9</td></tr><tr><td rowspan="3">NGC 1333-10</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.41</td><td>1.21 (0.02)</td><td>0.85 (0.01)</td><td>1.90 (0.02)</td><td>0.01</td><td>8.5</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.84</td><td>1.24 (0.02)</td><td>1.12 (0.01)</td><td>2.64 (0.02)</td><td>0.01</td><td>8.6</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.33</td><td>1.14 (0.02)</td><td>0.20 (0.01)</td><td>0.43 (0.02)</td><td>0.01</td><td>8.7</td></tr><tr><td rowspan="3">NGC 1333-12</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.15</td><td>0.86 (0.01)</td><td>0.08 (0.01)</td><td>0.17 (0.01)</td><td>0.03</td><td>7.8</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.20</td><td>1.02 (0.02)</td><td>0.12 (0.01)</td><td>0.29 (0.02)</td><td>0.03</td><td>7.5</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.39</td><td>0.96 (0.02)</td><td>0.22 (0.01)</td><td>0.41 (0.01)</td><td>0.02</td><td>7.7</td></tr><tr><td rowspan="3">NGC 1333-13</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.62</td><td>0.95 (0.02)</td><td>0.35 (0.01)</td><td>0.59 (0.01)</td><td>0.02</td><td>7.5</td></tr></tbody></table>
<table><caption>**Table 5**
(Continued)</caption><thead><tr><th>IDs</th><th>Transition<br>J, K</th><th>T<sub>MB</sub><sup>a</sup><br>(K)</th><th>dv<sup>b</sup><br>(km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<sub>eff</sub><sup>c</sup><br>(K km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<sup>d</sup><br>(K km s<sup>-1</sup>)</th><th>rms<sup>e</sup><br>(K)</th><th>V<sub>LSR</sub><br>(km s<sup>-1</sup>)</th></tr></thead><tbody><tr><td rowspan="3">NGC 1333-14</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.08</td><td>1.32 (0.02)</td><td>0.95 (0.01)</td><td>1.57 (0.02)</td><td>0.02</td><td>7.7</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.57</td><td>1.32 (0.02)</td><td>1.38 (0.01)</td><td>2.31 (0.02)</td><td>0.02</td><td>7.9</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.24</td><td>1.65 (0.03)</td><td>0.21 (0.01)</td><td>0.40 (0.02)</td><td>0.02</td><td>7.9</td></tr><tr><td rowspan="2">NGC 1333-15</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.24</td><td>0.95 (0.02)</td><td>0.21 (0.01)</td><td>0.24 (0.01)</td><td>0.02</td><td>7.4</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.30</td><td>1.03 (0.02)</td><td>0.26 (0.01)</td><td>0.35 (0.02)</td><td>0.02</td><td>7.5</td></tr><tr><td rowspan="3">L1448-1</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.93</td><td>1.17 (0.02)</td><td>1.45 (0.03)</td><td>1.28 (0.02)</td><td>0.02</td><td>4.5</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.22</td><td>1.18 (0.02)</td><td>1.96 (0.03)</td><td>1.80 (0.02)</td><td>0.02</td><td>4.6</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.23</td><td>1.14 (0.02)</td><td>0.35 (0.03)</td><td>0.39 (0.02)</td><td>0.02</td><td>4.7</td></tr><tr><td rowspan="3">L1448-2</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.34</td><td>1.03 (0.02)</td><td>2.52 (0.03)</td><td>1.74 (0.02)</td><td>0.02</td><td>4.5</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.73</td><td>1.09 (0.02)</td><td>3.26 (0.03)</td><td>2.99 (0.02)</td><td>0.02</td><td>4.3</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.39</td><td>1.56 (0.03)</td><td>0.74 (0.03)</td><td>1.32 (0.03)</td><td>0.02</td><td>4.7</td></tr><tr><td rowspan="3">L1448-3</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.64</td><td>1.77 (0.03)</td><td>0.69 (0.02)</td><td>2.58 (0.03)</td><td>0.02</td><td>4.8</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.74</td><td>1.71 (0.03)</td><td>0.80 (0.02)</td><td>1.70 (0.03)</td><td>0.02</td><td>5.0</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.08</td><td>1.30 (0.02)</td><td>0.09 (0.02)</td><td>0.11 (0.02)</td><td>0.02</td><td>5.0</td></tr><tr><td rowspan="3">L1448-4</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.92</td><td>0.81 (0.01)</td><td>1.91 (0.02)</td><td>1.74 (0.01)</td><td>0.02</td><td>4.1</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>2.39</td><td>0.87 (0.01)</td><td>2.38 (0.02)</td><td>2.34 (0.01)</td><td>0.02</td><td>4.3</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.35</td><td>0.84 (0.01)</td><td>0.35 (0.02)</td><td>0.34 (0.01)</td><td>0.02</td><td>4.3</td></tr><tr><td rowspan="3">L1448-5</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>2.31</td><td>1.05 (0.02)</td><td>1.57 (0.01)</td><td>5.19 (0.02)</td><td>0.02</td><td>4.1</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>2.65</td><td>1.10 (0.02)</td><td>1.80 (0.01)</td><td>6.27 (0.02)</td><td>0.02</td><td>4.3</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.49</td><td>0.92 (0.02)</td><td>0.33 (0.01)</td><td>1.12 (0.02)</td><td>0.02</td><td>4.3</td></tr><tr><td rowspan="3">IC 348-1</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.93</td><td>1.25 (0.02)</td><td>0.80 (0.01)</td><td>1.21 (0.02)</td><td>0.02</td><td>9.1</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.31</td><td>1.24 (0.02)</td><td>1.13 (0.01)</td><td>1.81 (0.02)</td><td>0.02</td><td>9.3</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.25</td><td>1.14 (0.02)</td><td>0.22 (0.01)</td><td>0.40 (0.02)</td><td>0.02</td><td>9.3</td></tr><tr><td rowspan="3">IC 348-2</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.49</td><td>0.90 (0.01)</td><td>0.53 (0.02)</td><td>0.49 (0.01)</td><td>0.02</td><td>8.8</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.69</td><td>0.89 (0.01)</td><td>0.76 (0.02)</td><td>0.77 (0.01)</td><td>0.02</td><td>8.5</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.13</td><td>0.98 (0.02)</td><td>0.15 (0.02)</td><td>0.16 (0.01)</td><td>0.02</td><td>8.9</td></tr><tr><td rowspan="3">IC 348-3</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.24</td><td>1.48 (0.02)</td><td>0.26 (0.02)</td><td>0.40 (0.05)</td><td>0.02</td><td>10</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.31</td><td>1.59 (0.02)</td><td>0.35 (0.02)</td><td>0.57 (0.05)</td><td>0.02</td><td>10</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.72</td><td>0.88 (0.01)</td><td>0.64 (0.01)</td><td>0.76 (0.01)</td><td>0.02</td><td>8.4</td></tr><tr><td rowspan="3">Barnard 5</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.43</td><td>1.00 (0.02)</td><td>0.36 (0.01)</td><td>0.43 (0.02)</td><td>0.02</td><td>9.9</td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.60</td><td>1.02 (0.02)</td><td>0.51 (0.01)</td><td>0.63 (0.02)</td><td>0.02</td><td>9.7</td></tr><tr><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.16</td><td>1.35 (0.02)</td><td>1.25 (0.02)</td><td>1.94 (0.02)</td><td>0.02</td><td>6.5</td></tr><tr><td rowspan="3">B1-1</td><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.60</td><td>1.27 (0.02)</td><td>1.72 (0.02)</td><td>2.44 (0.02)</td><td>0.02</td><td>6.3</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.18</td><td>1.33 (0.02)</td><td>0.19 (0.02)</td><td>0.25 (0.02)</td><td>0.02</td><td>6.3</td></tr><tr><td>J = 2-1, K = 1 E<sup>-</sup></td><td>1.33</td><td>0.86 (0.01)</td><td>0.90 (0.01)</td><td>1.25 (0.01)</td><td>0.02</td><td>6.5</td></tr><tr><td rowspan="3">B1-2</td><td>J = 2-1, K = 0 A<sup>+</sup></td><td>1.62</td><td>0.93 (0.02)</td><td>1.10 (0.01)</td><td>1.64 (0.01)</td><td>0.02</td><td>6.7</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.18</td><td>0.89 (0.01)</td><td>0.12 (0.01)</td><td>0.15 (0.01)</td><td>0.02</td><td>6.7</td></tr><tr><td>J = 2-1, K = 1 E<sup>-</sup></td><td>2.24</td><td>1.16 (0.02)</td><td>2.86 (0.02)</td><td>3.23 (0.02)</td><td>0.02</td><td>6.5</td></tr><tr><td rowspan="3">B1-3</td><td>J = 2-1, K = 0 A<sup>+</sup></td><td>2.97</td><td>1.19 (0.02)</td><td>3.80 (0.02)</td><td>4.47 (0.02)</td><td>0.02</td><td>6.3</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.45</td><td>1.22 (0.02)</td><td>0.58 (0.02)</td><td>0.66 (0.02)</td><td>0.02</td><td>6.3</td></tr><tr><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.66</td><td>0.90 (0.01)</td><td>0.72 (0.02)</td><td>0.63 (0.01)</td><td>0.02</td><td>7.2</td></tr><tr><td rowspan="3">B1-4</td><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.98</td><td>0.88 (0.01)</td><td>1.06 (0.02)</td><td>0.86 (0.01)</td><td>0.02</td><td>7.0</td></tr><tr><td>J = 2-1, K = 0 E<sup>+</sup></td><td>0.10</td><td>0.80 (0.01)</td><td>0.11 (0.02)</td><td>0.09 (0.01)</td><td>0.02</td><td>7.1</td></tr><tr><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.29</td><td>0.92 (0.02)</td><td>0.27 (0.01)</td><td>0.34 (0.01)</td><td>0.02</td><td>7.2</td></tr><tr><td rowspan="3">B1-5</td><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.40</td><td>1.10 (0.02)</td><td>0.37 (0.01)</td><td>0.53 (0.02)</td><td>0.02</td><td>7.0</td></tr><tr><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.19</td><td>0.61 (0.01)</td><td>0.16 (0.01)</td><td>0.11 (0.01)</td><td>0.02</td><td>5.2<sup>f</sup></td></tr><tr><td>J = 2-1, K = 1 E<sup>+</sup></td><td>0.22</td><td>0.79 (0.01)</td><td>0.18 (0.01)</td><td>0.17 (0.01)</td><td>0.02</td><td>5.4<sup>f</sup></td></tr><tr><td rowspan="3">L1455-1</td><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.34</td><td>1.24 (0.02)</td><td>0.41 (0.02)</td><td>0.55 (0.02)</td><td>0.02</td><td>4.8<sup>f</sup></td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.49</td><td>1.27 (0.02)</td><td>0.59 (0.02)</td><td>0.87 (0.02)</td><td>0.02</td><td>5.0<sup>f</sup></td></tr><tr><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.33</td><td>1.67 (0.03)</td><td>0.26 (0.01)</td><td>0.54 (0.03)</td><td>0.02</td><td>5.6<sup>f</sup></td></tr><tr><td rowspan="3">L1455-2</td><td>J = 2-1, K = 1 E<sup>+</sup></td><td>0.49</td><td>1.65 (0.03)</td><td>0.40 (0.01)</td><td>0.78(0.02)</td><td>0.02</td><td>5.8<sup>f</sup></td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.49</td><td>1.65 (0.03)</td><td>0.36 (0.02)</td><td>0.61 (0.02)</td><td>0.02</td><td>5.2<sup>f</sup></td></tr><tr><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.33</td><td>1.46 (0.02)</td><td>0.50 (0.02)</td><td>0.88 (0.02)</td><td>0.02</td><td>5.0<sup>f</sup></td></tr><tr><td rowspan="3">L1455-3</td><td>J = 2-1, K = 1 E<sup>+</sup></td><td>0.45</td><td>1.41 (0.02)</td><td>0.50 (0.02)</td><td>0.88 (0.02)</td><td>0.02</td><td>5.0<sup>f</sup></td></tr><tr><td>J = 2-1, K = 0 A<sup>+</sup></td><td>0.45</td><td>1.41 (0.02)</td><td>0.50 (0.02)</td><td>0.88 (0.02)</td><td>0.02</td><td>5.0<sup>f</sup></td></tr><tr><td>J = 2-1, K = 1 E<sup>-</sup></td><td>0.33</td><td>1.46 (0.02)</td><td>0.36 (0.02)</td><td>0.61 (0.02)</td><td>0.02</td><td>5.2<sup>f</sup></td></tr></tbody></table>

**Notes.**

a Obtained by the Gaussian fit.

b The wing components are excluded in the Gaussian fit.

c Derived using the C<sub>2</sub>H velocity widths.

d The wing components are included when calculating the integrated intensity.

e The rms noise averaged over the line width.

f Only for the L1455 region, V<sub>LSR</sub> is corrected by 9 km s<sup>-1</sup> due to a problem with the NRO 45 m. It is recovered using the V<sub>LSR</sub> obtained by IRAM 30 m.
<table><caption>**Table 6**
Line Parameters of the C₂H (N = 3–2) Lines Observed with IRAM 30 m</caption><thead><tr><th>IDs</th><th>Transition<br>J, F</th><th>T<sub>MB</sub><sup>a</sup><br>(K)</th><th>dv<br>(km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<br>(K km s<sup>-1</sup>)</th><th>rms<sup>b</sup><br>(K)</th><th>V<sub>LSR</sub><br>(km s<sup>-1</sup>)</th></tr></thead><tbody><tr><td rowspan="4">NGC 1333-1</td><td>J = 5/2-3/2, F = 2-1</td><td>0.16</td><td>2.62 (0.20)</td><td>0.45 (0.02)</td><td>0.03</td><td>6.4</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.16</td><td>2.27 (0.20)</td><td>0.39 (0.02)</td><td>0.03</td><td>6.9</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.22</td><td>2.43 (0.20)</td><td>0.57 (0.02)</td><td>0.03</td><td>6.6</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.27</td><td>2.10 (0.20)</td><td>0.60 (0.02)</td><td>0.03</td><td>6.9</td></tr><tr><td rowspan="4">NGC 1333-2</td><td>J = 5/2-3/2, F = 2-1</td><td>0.42</td><td>1.30 (0.07)</td><td>0.58 (0.02)</td><td>0.03</td><td>7.6</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.60</td><td>1.19 (0.04)</td><td>0.76 (0.02)</td><td>0.03</td><td>7.6</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.61</td><td>1.26 (0.05)</td><td>0.83 (0.02)</td><td>0.03</td><td>7.5</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.72</td><td>1.45 (0.04)</td><td>1.10 (0.03)</td><td>0.03</td><td>7.5</td></tr><tr><td rowspan="4">NGC 1333-3</td><td>J = 5/2-3/2, F = 2-1</td><td>0.99</td><td>0.91 (0.22)</td><td>0.96 (0.05)</td><td>0.03</td><td>8.2</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>1.37</td><td>0.97 (0.22)</td><td>1.41 (0.05)</td><td>0.03</td><td>8.2</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>1.46</td><td>0.94 (0.22)</td><td>1.46 (0.05)</td><td>0.03</td><td>8.2</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>1.83</td><td>0.95 (0.22)</td><td>1.85 (0.05)</td><td>0.03</td><td>8.1</td></tr><tr><td rowspan="4">NGC 1333-4</td><td>J = 5/2-3/2, F = 2-1</td><td>0.36</td><td>0.92 (0.06)</td><td>0.36 (0.02)</td><td>0.03</td><td>8.7</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.62</td><td>0.85 (0.03)</td><td>0.56 (0.02)</td><td>0.03</td><td>8.7</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.65</td><td>0.97 (0.03)</td><td>0.67 (0.02)</td><td>0.03</td><td>8.6</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.76</td><td>1.05 (0.03)</td><td>0.85 (0.02)</td><td>0.03</td><td>8.6</td></tr><tr><td rowspan="4">NGC 1333-5</td><td>J = 5/2-3/2, F = 2-1</td><td>0.56</td><td>0.94 (0.04)</td><td>0.56 (0.02)</td><td>0.03</td><td>7.7</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.78</td><td>0.90 (0.03)</td><td>0.75 (0.02)</td><td>0.03</td><td>7.7</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.74</td><td>0.94 (0.03)</td><td>0.74 (0.02)</td><td>0.03</td><td>7.7</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.97</td><td>0.93 (0.02)</td><td>0.95 (0.02)</td><td>0.03</td><td>7.6</td></tr><tr><td rowspan="4">NGC 1333-6</td><td>J = 5/2-3/2, F = 2-1</td><td>0.85</td><td>0.80 (0.02)</td><td>0.72 (0.02)</td><td>0.02</td><td>7.2</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>1.17</td><td>0.85 (0.02)</td><td>1.05 (0.02)</td><td>0.02</td><td>7.3</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>1.21</td><td>0.85 (0.02)</td><td>1.09 (0.02)</td><td>0.02</td><td>7.2</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>1.53</td><td>0.86 (0.01)</td><td>1.39 (0.02)</td><td>0.02</td><td>7.2</td></tr><tr><td rowspan="4">NGC 1333-7</td><td>J = 5/2-3/2, F = 2-1</td><td>0.26</td><td>1.76 (0.22)</td><td>0.49 (0.02)</td><td>0.02</td><td>8.0</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.40</td><td>1.33 (0.22)</td><td>0.56 (0.02)</td><td>0.02</td><td>8.0</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.44</td><td>1.46 (0.22)</td><td>0.68 (0.02)</td><td>0.02</td><td>8.0</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.58</td><td>1.27 (0.22)</td><td>0.78 (0.02)</td><td>0.02</td><td>7.9</td></tr><tr><td rowspan="4">NGC 1333-8</td><td>J = 5/2-3/2, F = 2-1</td><td>0.44</td><td>1.06 (0.04)</td><td>0.49 (0.02)</td><td>0.02</td><td>6.6</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.64</td><td>1.09 (0.03)</td><td>0.75 (0.02)</td><td>0.02</td><td>6.6</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.66</td><td>1.06 (0.03)</td><td>0.75 (0.02)</td><td>0.02</td><td>6.6</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.89</td><td>1.12 (0.02)</td><td>1.06 (0.02)</td><td>0.02</td><td>6.6</td></tr><tr><td rowspan="4">NGC 1333-9</td><td>J = 5/2-3/2, F = 2-1</td><td>0.33</td><td>1.54 (0.07)</td><td>0.54 (0.02)</td><td>0.02</td><td>7.6</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.47</td><td>1.45 (0.05)</td><td>0.72 (0.02)</td><td>0.02</td><td>7.6</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.51</td><td>1.58 (0.06)</td><td>0.86 (0.02)</td><td>0.02</td><td>7.6</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.65</td><td>1.47 (0.04)</td><td>1.01 (0.02)</td><td>0.02</td><td>7.5</td></tr><tr><td rowspan="4">NGC 1333-10</td><td>J = 5/2-3/2, F = 3-2</td><td>0.10</td><td>1.25 (0.18)</td><td>0.13 (0.02)</td><td>0.02</td><td>7.6</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.12</td><td>1.09 (0.18)</td><td>0.14 (0.02)</td><td>0.02</td><td>7.5</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.13</td><td>1.49 (0.24)</td><td>0.21 (0.02)</td><td>0.02</td><td>7.3</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.18</td><td>0.63 (0.09)</td><td>0.12 (0.01)</td><td>0.02</td><td>8.5</td></tr><tr><td rowspan="4">NGC 1333-11</td><td>J = 5/2-3/2, F = 3-2</td><td>0.27</td><td>0.58 (0.06)</td><td>0.17 (0.01)</td><td>0.02</td><td>8.5</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.25</td><td>0.56 (0.07)</td><td>0.15 (0.01)</td><td>0.02</td><td>8.5</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.31</td><td>0.50 (0.05)</td><td>0.17 (0.01)</td><td>0.02</td><td>8.5</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.12</td><td>0.47 (0.14)</td><td>0.06 (0.01)</td><td>0.02</td><td>7.5</td></tr><tr><td rowspan="4">NGC 1333-12</td><td>J = 5/2-3/2, F = 3-2</td><td>0.14</td><td>0.55 (0.11)</td><td>0.08 (0.01)</td><td>0.02</td><td>7.6</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.16</td><td>0.63 (0.09)</td><td>0.11 (0.01)</td><td>0.02</td><td>7.5</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.17</td><td>0.54 (0.07)</td><td>0.10 (0.01)</td><td>0.02</td><td>7.5</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.14</td><td>0.53 (0.10)</td><td>0.08 (0.01)</td><td>0.02</td><td>7.5</td></tr><tr><td rowspan="4">NGC 1333-13</td><td>J = 5/2-3/2, F = 3-2</td><td>0.24</td><td>0.48 (0.06)</td><td>0.12 (0.01)</td><td>0.02</td><td>7.5</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.29</td><td>0.48 (0.05)</td><td>0.15 (0.01)</td><td>0.02</td><td>7.5</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.35</td><td>0.60 (0.05)</td><td>0.22 (0.01)</td><td>0.02</td><td>7.5</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.13</td><td>1.15 (0.16)</td><td>0.16 (0.02)</td><td>0.02</td><td>7.9</td></tr><tr><td rowspan="4">NGC 1333-14</td><td>J = 5/2-3/2, F = 3-2</td><td>0.29</td><td>0.70 (0.05)</td><td>0.21 (0.01)</td><td>0.02</td><td>7.9</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.26</td><td>0.76 (0.06)</td><td>0.21 (0.01)</td><td>0.02</td><td>7.8</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.35</td><td>0.68 (0.04)</td><td>0.25 (0.01)</td><td>0.02</td><td>7.8</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.10</td><td>0.87 (0.17)</td><td>0.09 (0.02)</td><td>0.02</td><td>8.3</td></tr><tr><td rowspan="4">NGC 1333-15</td><td>J = 7/2-5/2, F = 3-2</td><td>0.10</td><td>0.96 (0.14)</td><td>0.10 (0.01)</td><td>0.02</td><td>8.2</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.12</td><td>0.61 (0.10)</td><td>0.08 (0.01)</td><td>0.02</td><td>8.2</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.10</td><td>1.36 (0.78)</td><td>0.14 (0.03)</td><td>0.02</td><td>6.6</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.14</td><td>2.34 (0.78)</td><td>0.35 (0.03)</td><td>0.02</td><td>6.2</td></tr></tbody></table>
<table><caption>**Table 6**
(Continued)</caption><thead><tr><th>IDs</th><th>Transition<br>J, F</th><th>T<sub>MB</sub><sup>a</sup><br>(K)</th><th>dv<br>(km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<br>(K km s<sup>-1</sup>)</th><th>rms<sup>b</sup><br>(K)</th><th>V<sub>LSR</sub><br>(km s<sup>-1</sup>)</th></tr></thead><tbody><tr><td rowspan="6">NGC 1333-17</td><td>J = 7/2-5/2, F = 3-2</td><td>0.14</td><td>1.85 (0.78)</td><td>0.28 (0.03)</td><td>0.02</td><td>6.5</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.20</td><td>2.41 (0.78)</td><td>0.51 (0.03)</td><td>0.02</td><td>6.3</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.86</td><td>1.01 (0.20)</td><td>0.97 (0.05)</td><td>0.04</td><td>8.7</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>1.15</td><td>1.13 (0.20)</td><td>1.38 (0.05)</td><td>0.04</td><td>8.7</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>1.24</td><td>1.07 (0.20)</td><td>1.40 (0.05)</td><td>0.04</td><td>8.7</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>1.54</td><td>1.12 (0.20)</td><td>1.84 (0.05)</td><td>0.04</td><td>8.7</td></tr><tr><td rowspan="6">L1448-1</td><td>J = 5/2-3/2, F = 2-1</td><td>0.44</td><td>1.44 (0.06)</td><td>0.68 (0.02)</td><td>0.03</td><td>4.0</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.66</td><td>1.48 (0.05)</td><td>1.05 (0.03)</td><td>0.03</td><td>4.0</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.74</td><td>1.38 (0.04)</td><td>1.09 (0.03)</td><td>0.03</td><td>4.0</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.86</td><td>1.56 (0.04)</td><td>1.42 (0.03)</td><td>0.03</td><td>3.9</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>1.01</td><td>1.70 (0.22)</td><td>1.83 (0.07)</td><td>0.03</td><td>4.8</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>1.33</td><td>1.72 (0.22)</td><td>2.44 (0.07)</td><td>0.03</td><td>4.8</td></tr><tr><td rowspan="6">L1448-2</td><td>J = 7/2-5/2, F = 3-2</td><td>1.36</td><td>1.80 (0.22)</td><td>2.61 (0.07)</td><td>0.03</td><td>4.8</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>1.59</td><td>1.85 (0.22)</td><td>3.12 (0.07)</td><td>0.03</td><td>4.7</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.45</td><td>1.03 (0.06)</td><td>0.50 (0.02)</td><td>0.03</td><td>5.1</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.71</td><td>0.96 (0.04)</td><td>0.73 (0.02)</td><td>0.03</td><td>5.2</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.77</td><td>0.98 (0.03)</td><td>0.81 (0.02)</td><td>0.03</td><td>5.2</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.93</td><td>1.09 (0.03)</td><td>1.08 (0.02)</td><td>0.03</td><td>5.1</td></tr><tr><td rowspan="6">L1448-3</td><td>J = 5/2-3/2, F = 2-1</td><td>1.05</td><td>0.89 (0.02)</td><td>0.99 (0.02)</td><td>0.03</td><td>4.0</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>1.36</td><td>0.91 (0.02)</td><td>1.33 (0.02)</td><td>0.03</td><td>4.1</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>1.45</td><td>0.96 (0.02)</td><td>1.47 (0.02)</td><td>0.03</td><td>4.0</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>1.58</td><td>0.98 (0.01)</td><td>1.65 (0.01)</td><td>0.03</td><td>4.0</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.22</td><td>0.57 (0.12)</td><td>0.13 (0.03)</td><td>0.05</td><td>4.1</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.35</td><td>0.61 (0.08)</td><td>0.23 (0.03)</td><td>0.05</td><td>4.1</td></tr><tr><td rowspan="6">IC 348-1</td><td>J = 7/2-5/2, F = 3-2</td><td>0.38</td><td>0.50 (0.08)</td><td>0.20 (0.03)</td><td>0.05</td><td>4.2</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.40</td><td>0.87 (0.08)</td><td>0.37 (0.03)</td><td>0.05</td><td>4.2</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.60</td><td>0.78 (0.04)</td><td>0.49 (0.02)</td><td>0.03</td><td>9.1</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.75</td><td>0.82 (0.03)</td><td>0.65 (0.02)</td><td>0.03</td><td>9.1</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.81</td><td>0.80 (0.03)</td><td>0.69 (0.02)</td><td>0.03</td><td>9.1</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>1.03</td><td>0.83 (0.02)</td><td>0.91 (0.02)</td><td>0.03</td><td>9.0</td></tr><tr><td rowspan="6">IC 348-2</td><td>J = 5/2-3/2, F = 2-1</td><td>0.61</td><td>1.00 (0.03)</td><td>0.66 (0.02)</td><td>0.02</td><td>8.6</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.85</td><td>1.03 (0.02)</td><td>0.93 (0.02)</td><td>0.02</td><td>8.7</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.89</td><td>1.03 (0.02)</td><td>0.97 (0.02)</td><td>0.02</td><td>8.6</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>1.08</td><td>1.03 (0.02)</td><td>1.19 (0.02)</td><td>0.02</td><td>8.6</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.16</td><td>0.97 (0.11)</td><td>0.16 (0.02)</td><td>0.02</td><td>10</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.23</td><td>1.45 (0.12)</td><td>0.24 (0.02)</td><td>0.02</td><td>10</td></tr><tr><td rowspan="6">IC 348-4</td><td>J = 7/2-5/2, F = 3-2</td><td>0.26</td><td>1.01 (0.06)</td><td>0.28 (0.02)</td><td>0.02</td><td>10</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.32</td><td>1.19 (0.07)</td><td>0.41 (0.02)</td><td>0.02</td><td>10</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.45</td><td>0.82 (0.04)</td><td>0.39 (0.02)</td><td>0.02</td><td>8.5</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.70</td><td>0.82 (0.02)</td><td>0.61 (0.02)</td><td>0.02</td><td>8.5</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.70</td><td>0.83 (0.03)</td><td>0.60 (0.02)</td><td>0.02</td><td>8.5</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.95</td><td>0.84 (0.02)</td><td>0.85 (0.02)</td><td>0.02</td><td>8.5</td></tr><tr><td rowspan="6">Barnard 5</td><td>J = 5/2-3/2, F = 2-1</td><td>0.81</td><td>0.77 (0.02)</td><td>0.66 (0.02)</td><td>0.03</td><td>10</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>1.13</td><td>0.77 (0.02)</td><td>0.93 (0.02)</td><td>0.03</td><td>10</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>1.12</td><td>0.82 (0.02)</td><td>0.98 (0.02)</td><td>0.03</td><td>10</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>1.38</td><td>0.85 (0.02)</td><td>1.24 (0.02)</td><td>0.03</td><td>10</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.27</td><td>1.06 (0.09)</td><td>0.30 (0.02)</td><td>0.03</td><td>6.4</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.41</td><td>0.92 (0.07)</td><td>0.40 (0.02)</td><td>0.03</td><td>6.3</td></tr><tr><td rowspan="6">B1-1</td><td>J = 7/2-5/2, F = 3-2</td><td>0.43</td><td>1.01 (0.07)</td><td>0.46 (0.02)</td><td>0.03</td><td>6.4</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.54</td><td>1.04 (0.06)</td><td>0.60 (0.02)</td><td>0.03</td><td>6.3</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.74</td><td>0.62 (0.02)</td><td>0.49 (0.01)</td><td>0.03</td><td>6.6</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.92</td><td>0.67 (0.02)</td><td>0.65 (0.02)</td><td>0.03</td><td>6.6</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.97</td><td>0.61 (0.02)</td><td>0.63 (0.01)</td><td>0.03</td><td>6.6</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>1.07</td><td>0.66 (0.02)</td><td>0.76 (0.02)</td><td>0.03</td><td>6.6</td></tr><tr><td rowspan="6">B1-2</td><td>J = 5/2-3/2, F = 2-1</td><td>0.27</td><td>1.20 (0.10)</td><td>0.34 (0.02)</td><td>0.03</td><td>6.4</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.39</td><td>1.08 (0.06)</td><td>0.45 (0.02)</td><td>0.03</td><td>6.3</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.39</td><td>1.59 (0.11)</td><td>0.65 (0.03)</td><td>0.03</td><td>6.4</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.57</td><td>0.93 (0.04)</td><td>0.57 (0.02)</td><td>0.03</td><td>6.3</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.50</td><td>0.98 (0.22)</td><td>0.52 (0.03)</td><td>0.03</td><td>6.9</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.71</td><td>1.04 (0.22)</td><td>0.78 (0.03)</td><td>0.03</td><td>6.9</td></tr></tbody></table>
<table><caption>**Table 6**
(Continued)</caption><thead><tr><th>IDs</th><th>Transition<br>J, F</th><th>T<sub>MB</sub><sup>a</sup><br>(K)</th><th>dv<br>(km s<sup>-1</sup>)</th><th>∫T<sub>MB</sub>dv<br>(K km s<sup>-1</sup>)</th><th>rms<sup>b</sup><br>(K)</th><th>V<sub>LSR</sub><br>(km s<sup>-1</sup>)</th></tr></thead><tbody><tr><td rowspan="6">B1-5</td><td>J = 7/2-5/2, F = 3-2</td><td>0.77</td><td>1.03 (0.22)</td><td>0.85 (0.03)</td><td>0.03</td><td>6.9</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.92</td><td>1.05 (0.22)</td><td>1.02 (0.03)</td><td>0.03</td><td>6.8</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.29</td><td>0.82 (0.07)</td><td>0.25 (0.02)</td><td>0.03</td><td>7.0</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.40</td><td>0.76 (0.04)</td><td>0.32 (0.02)</td><td>0.03</td><td>7.0</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.41</td><td>0.96 (0.06)</td><td>0.41 (0.02)</td><td>0.03</td><td>7.0</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.50</td><td>0.90 (0.05)</td><td>0.48 (0.02)</td><td>0.03</td><td>7.0</td></tr><tr><td rowspan="6">L1455-1</td><td>J = 5/2-3/2, F = 2-1</td><td>0.43</td><td>0.72 (0.22)</td><td>0.33 (0.02)</td><td>0.02</td><td>5.2</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.59</td><td>0.81 (0.22)</td><td>0.50 (0.02)</td><td>0.02</td><td>5.2</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.63</td><td>0.81 (0.22)</td><td>0.54 (0.02)</td><td>0.02</td><td>5.2</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.69</td><td>0.87 (0.22)</td><td>0.63 (0.02)</td><td>0.02</td><td>5.2</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.52</td><td>1.09 (0.04)</td><td>0.61 (0.02)</td><td>0.03</td><td>4.9</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.69</td><td>1.15 (0.03)</td><td>0.84 (0.02)</td><td>0.03</td><td>4.9</td></tr><tr><td rowspan="6">L1455-2</td><td>J = 7/2-5/2, F = 3-2</td><td>0.80</td><td>1.12 (0.03)</td><td>0.96 (0.02)</td><td>0.03</td><td>4.9</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.96</td><td>1.20 (0.03)</td><td>1.23 (0.02)</td><td>0.03</td><td>4.9</td></tr><tr><td>J = 5/2-3/2, F = 2-1</td><td>0.43</td><td>0.79 (0.04)</td><td>0.36 (0.02)</td><td>0.03</td><td>4.8</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.66</td><td>0.75 (0.03)</td><td>0.52 (0.02)</td><td>0.03</td><td>4.8</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.67</td><td>0.73 (0.03)</td><td>0.52 (0.02)</td><td>0.03</td><td>4.8</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.88</td><td>0.75 (0.02)</td><td>0.71 (0.02)</td><td>0.03</td><td>4.7</td></tr><tr><td rowspan="4">L1455-4</td><td>J = 5/2-3/2, F = 2-1</td><td>0.23</td><td>1.01 (0.08)</td><td>0.25 (0.02)</td><td>0.03</td><td>5.3</td></tr><tr><td>J = 5/2-3/2, F = 3-2</td><td>0.32</td><td>1.00 (0.06)</td><td>0.33 (0.02)</td><td>0.03</td><td>5.3</td></tr><tr><td>J = 7/2-5/2, F = 3-2</td><td>0.35</td><td>1.09 (0.06)</td><td>0.40 (0.02)</td><td>0.03</td><td>5.3</td></tr><tr><td>J = 7/2-5/2, F = 4-3</td><td>0.44</td><td>1.08 (0.05)</td><td>0.50 (0.02)</td><td>0.03</td><td>5.2</td></tr></tbody></table>

**Notes.**

<sup>a</sup> Obtained by the Gaussian fit.

<sup>b</sup> The rms noise averaged over the line width.

component of C$_2$H in Table 2 in order to avoid the possible saturation effect as much as possible. Since broad wing components of the CH$_3$OH lines would likely originate from outflow shocks, we need to exclude them to discuss the chemical compositions of protostellar envelopes. For this purpose, the C$_2$H velocity width (a full width at half maximum, FWHM) is employed as the velocity range for the integrated intensities of the CH$_3$OH lines. We use this simple procedure because fitting by a double (or multiple) Gaussian function does not always work, due to asymmetric line profiles. The result is shown in Figure 5(a). The intensities vary over one or two orders of magnitude among the sources, and no correlation can be seen between the C$_2$H and CH$_3$OH intensities. Indeed, the correlation coefficient is 0.04 for Figure 5(a), where the upper limits are not involved in the calculation of the correlation coefficient. The C$_2$H/CH$_3$OH integrated intensity ratio differs at most by a factor of 100. Even if we focus on only the sources in the NGC 1333 cloud, the correlation plot still shows a large scatter (Figure 5(a)).

For reference, we prepare the same plot using the integrated intensities of CH$_3$OH including the wing components, as shown in Figure 5(b). The plots with and without the wing component of CH$_3$OH do not differ from each other as a whole. In general, CH$_3$OH is not only abundant in hot inner envelopes but also in outflow-shocked regions (Bachiller et al. 1998). CH$_3$OH is formed through hydrogenation of CO depleted on a grain mantle in a cold starless phase (e.g., Tielens & Hagen 1982; Watanabe & Kouchi 2002; Soma et al. 2015), and is liberated into the gas-phase in hot regions ($T > 100$ K) or in outflow-shocked regions (e.g., Bachiller & Pérez Gutiérrez 1997; Saruwatari et al. 2011). Furthermore, it can also be liberated even in cold regions to some extent, through

non-thermal desorption processes (e.g., Bizzocchi et al. 2014; Soma et al. 2015; Spezzano et al. 2016a, 2016b). For this reason, abundant CH$_3$OH in the gas-phase means abundant CH$_3$OH in grain a mantle just before the onset of star formation, whatever its liberation mechanism is. Conversely, CH$_3$OH cannot be abundant in the gas-phase, if it is deficient on a grain mantle. Indeed, the CH$_3$OH emission is faint in the WCCC source, L1527, even for the outflow components (e.g., Sakai et al. 2014a; Takakuwa et al. 2000). Hence, the inclusion of the wing components originating from the outflow-shocked regions in the integrated intensity of CH$_3$OH will not seriously affect the trend that CH$_3$OH is abundant in the source. However, we use the integrated intensity without the wing components in the following discussion for fair comparison, as stated above.

In addition, the correlation plot of integrated intensities of the CH$_3$OH and c-C$_3$H$_2$ (3$_{2,1}$–2$_{1,2}$, $E_u = 18$ K) lines is shown (see Figure 5(c)). No correlation can be found in this plot, similar to the correlation plot between the integrated intensities of C$_2$H and CH$_3$OH. The correlation coefficient is 0.04.

In contrast, the integrated intensities of the C$_2$H ($N = 3-2$, $J = 5/2-3/2$, $F = 3-2$, $E_u = 25$ K) and c-C$_3$H$_2$ (3$_{2,1}$–2$_{1,2}$, $E_u = 18$ K) lines are correlated with each other (see Figure 5(d)). The correlation coefficient is 0.75, where the upper limit values are not included. Although C$_2$H is thought to be the photodissociation region (PDR) tracer (e.g., Cuadrado et al. 2015), the clear correlation between C$_2$H and c-C$_3$H$_2$ implies that the C$_2$H lines trace the dense core rather than the PDRs in this study (See Section 4.1).

The correlation of C$_2$H and c-C$_3$H$_2$ has been reported for diffuse clouds and PDRs (e.g., Gerin et al. 2011; Guzmán et al. 2015). In addition, C$_2$H and c-C$_3$H$_2$ exist in dense clouds,
<table><caption>**Table 7**
Line Parameters of the c-C$_3$H$_2$ (3$_{2,1}$−2$_{1,2}$) Lines Observed with IRAM 30 m</caption><thead><tr><th>IDs</th><th><i>T</i><sub>MB</sub><sup>a</sup><br>(K)</th><th><i>dv</i><br>(km s<sup>-1</sup>)</th><th>∫<i>T</i><sub>MB</sub><i>dv</i><br>(K km s<sup>-1</sup>)</th><th>rms<sup>b</sup><br>(K)</th><th><i>V</i><sub>LSR</sub><br>(km s<sup>-1</sup>)</th></tr></thead><tbody><tr><td>NGC 1333-1</td><td>0.23</td><td>0.35 (0.08)</td><td>0.08 (0.02)</td><td>0.04</td><td>6.5</td></tr><tr><td>NGC 1333-2</td><td>0.25</td><td>1.03 (0.10)</td><td>0.27 (0.02)</td><td>0.03</td><td>7.5</td></tr><tr><td>NGC 1333-3</td><td>0.18</td><td>0.64 (0.08)</td><td>0.12 (0.02)</td><td>0.03</td><td>8.1</td></tr><tr><td>NGC 1333-4</td><td>0.09</td><td>0.72 (0.26)</td><td>0.07 (0.02)</td><td>0.03</td><td>8.6</td></tr><tr><td>NGC 1333-5</td><td>0.17</td><td>0.69 (0.12)</td><td>0.13 (0.02)</td><td>0.03</td><td>7.7</td></tr><tr><td>NGC 1333-6</td><td>0.66</td><td>0.67 (0.03)</td><td>0.47 (0.02)</td><td>0.03</td><td>7.3</td></tr><tr><td>NGC 1333-7</td><td>0.21</td><td>0.60 (0.08)</td><td>0.14 (0.02)</td><td>0.03</td><td>8.1</td></tr><tr><td>NGC 1333-8</td><td>0.11</td><td>0.90 (0.21)</td><td>0.11 (0.02)</td><td>0.03</td><td>6.6</td></tr><tr><td>NGC 1333-9</td><td>...</td><td>...</td><td>&lt;0.04</td><td>0.03</td><td>...</td></tr><tr><td>NGC 1333-10</td><td>...</td><td>...</td><td>&lt;0.04</td><td>0.02</td><td>...</td></tr><tr><td>NGC 1333-11</td><td>0.11</td><td>0.41 (0.11)</td><td>0.05 (0.01)</td><td>0.02</td><td>8.4</td></tr><tr><td>NGC 1333-12</td><td>...</td><td>...</td><td>&lt;0.03</td><td>0.02</td><td>...</td></tr><tr><td>NGC 1333-13</td><td>...</td><td>...</td><td>&lt;0.03</td><td>0.02</td><td>...</td></tr><tr><td>NGC 1333-14</td><td>0.12</td><td>0.60 (0.11)</td><td>0.07 (0.01)</td><td>0.02</td><td>7.7</td></tr><tr><td>NGC 1333-15</td><td>...</td><td>...</td><td>&lt;0.03</td><td>0.02</td><td>...</td></tr><tr><td>NGC 1333-16</td><td>0.12</td><td>0.72 (0.08)</td><td>0.10 (0.01)</td><td>0.08</td><td>6.8</td></tr><tr><td>NGC 1333-17</td><td>0.15</td><td>1.12 (0.04)</td><td>0.18 (0.01)</td><td>0.04</td><td>8.4</td></tr><tr><td>L1448-1</td><td>0.50</td><td>1.22 (0.06)</td><td>0.66 (0.03)</td><td>0.04</td><td>4.2</td></tr><tr><td>L1448-2</td><td>0.39</td><td>1.34 (0.07)</td><td>0.55 (0.03)</td><td>0.03</td><td>4.6</td></tr><tr><td>L1448-3</td><td>0.25</td><td>0.97 (0.10)</td><td>0.26 (0.02)</td><td>0.03</td><td>4.8</td></tr><tr><td>L1448-4</td><td>0.39</td><td>0.52 (0.04)</td><td>0.22 (0.02)</td><td>0.03</td><td>4.0</td></tr><tr><td>L1448-5</td><td>0.33</td><td>0.46 (0.05)</td><td>0.16 (0.02)</td><td>0.03</td><td>4.1</td></tr><tr><td>IC 348-1</td><td>0.37</td><td>0.61 (0.05)</td><td>0.24 (0.02)</td><td>0.03</td><td>9.0</td></tr><tr><td>IC 348-2</td><td>0.47</td><td>0.56 (0.03)</td><td>0.28 (0.01)</td><td>0.02</td><td>8.8</td></tr><tr><td>IC 348-3</td><td>...</td><td>...</td><td>&lt;0.04</td><td>0.02</td><td>...</td></tr><tr><td>IC 348-4</td><td>0.28</td><td>0.52 (0.04)</td><td>0.15 (0.01)</td><td>0.02</td><td>8.5</td></tr><tr><td>Barnard 5</td><td>0.22</td><td>0.89 (0.10)</td><td>0.21 (0.02)</td><td>0.02</td><td>10</td></tr><tr><td>B1-1</td><td>0.31</td><td>0.89 (0.05)</td><td>0.29 (0.02)</td><td>0.02</td><td>6.3</td></tr><tr><td>B1-2</td><td>0.36</td><td>0.65 (0.05)</td><td>0.25 (0.02)</td><td>0.02</td><td>6.5</td></tr><tr><td>B1-3</td><td>0.13</td><td>0.99 (0.15)</td><td>0.13 (0.02)</td><td>0.03</td><td>6.3</td></tr><tr><td>B1-4</td><td>0.36</td><td>0.75 (0.06)</td><td>0.28 (0.02)</td><td>0.03</td><td>6.9</td></tr><tr><td>B1-5</td><td>0.20</td><td>0.53 (0.06)</td><td>0.11 (0.02)</td><td>0.03</td><td>6.9</td></tr><tr><td>L1455-1</td><td>0.28</td><td>0.53 (0.04)</td><td>0.16 (0.01)</td><td>0.02</td><td>5.2</td></tr><tr><td>L1455-2</td><td>0.19</td><td>1.01 (0.13)</td><td>0.20 (0.02)</td><td>0.02</td><td>5.0</td></tr><tr><td>L1455-3</td><td>0.19</td><td>0.51 (0.07)</td><td>0.10 (0.01)</td><td>0.03</td><td>4.8</td></tr><tr><td>L1455-4</td><td>0.10</td><td>0.35 (0.17)</td><td>0.03 (0.01)</td><td>0.02</td><td>5.1</td></tr></tbody></table>

**Notes.** The errors are $1\sigma$. The upper limit to the integrated intensity is calculated as $\int T_{MB} dv < 3\sigma \times \sqrt{(dv/dv_{res})} dv_{res}$, where *dv* is the assumed line width (0.8 km s⁻¹) and *dv*<sub>res</sub> is the velocity resolution per channel.

including starless cores and protostellar cores (e.g., Sakai et al. 2008, 2014a; Koumpia et al. 2016, 2017). Since we observed the high excitation lines of C$_2$H and c-C$_3$H$_2$ toward the protostellar cores at almost the same distance, our result suggests that the correlation between the two lines holds in protostellar cores, as expected from carbon chemistry in dense clouds (Sakai & Yamamoto 2013; Yamamoto 2017). In contrast, Fontani et al. (2012) presented anti-correlation between the two molecules, C$_2$H and c-C$_3$H$_2$ in a UC H II region, suggesting a complex physical structure for the source.

### 3.3. Derivation of Rotation Temperatures and Column Densities

To investigate the chemical diversity, we derive the beam-averaged column densities of CH$_3$OH, C$_2$H, and c-C$_3$H$_2$ under the assumption of local thermodynamic equilibrium (LTE) conditions. The rotation temperature of CH$_3$OH (E state) was evaluated from the multiple transition lines with different upper

state energies, where a rotational diagram method assuming optically thin emission was used (e.g., Watanabe et al. 2015). We used the E state lines, because more lines are available than for the A state. Examples of the rotation diagrams prepared in our analyses are shown in Figure 6 (also see Figure 11).

The derived rotation temperature ranges from 8 to 21 K. The rotation temperatures of CH$_3$OH, derived for NGC 1333-1 (IRAS 4B), NGC 1333-2 (IRAS 2), L1448-2, and L1448-3 using the K structure lines of the *J* = 5–4 and *J* = 7–6 transition, are lower by 6–82 K than those reported by Maret et al. (2005). Maret et al. (2005) only employed the high excitation lines (*J* = 5–4 and *J* = 7–6) of CH$_3$OH in their analysis. In contrast, we employ the *J* = 2–1 lines instead of higher excitation lines, which would likely trace CH$_3$OH not only in a warm and dense part, but also in a colder envelope part. This seems to be a reason for the lower temperature obtained in our study.

It should be noted that we are observing the CH$_3$OH emission in the protostellar envelope. One may think that the CH$_3$OH emission mainly comes from the small hot region (~100 K) near the protostar. However, its contribution may not be dominant in our observations, because the rotation temperature is as low as 8–21 K. Rotation temperatures of 8–21 K are too low to trace hot corinos, even considering that CH$_3$OH emission is sub-thematically excited (e.g., Bachiller et al. 1998 and references therein). Moreover, we do not find any correlation between the CH$_3$OH intensity and the protostellar luminosity (Figure 7); higher-luminosity sources do not always give stronger CH$_3$OH emission in our observation.

The rotation temperature derived by the rotation diagram analysis depends on the assumed source size. If the source size is smaller than the observation beams both for the *J* = 2–1 (97 GHz) and *J* = 5–4 (242 GHz) lines, the rotation temperature derived above would be lower than our estimate, because the beam dilution effect is larger for the 97 GHz observation. If the emitting region is smaller for the 242 GHz line than for the 97 GHz line due to the higher critical density, the beam dilution effect can be larger for the 242 GHz line. In this case, the rotation temperature would be higher than our estimate. Although these two situations may be the case, we do not know the internal structure within the observation beam for individual sources. When the two above limitations are considered, assuming that the beam filling factor is unity provides a moderate estimate of the rotation temperature. Moreover, in the following sections we discuss the results within our sample sources, which are almost equally distant from the Sun. Thus, the systematic errors due to the beam dilution effect would be mitigated to some extent for the column density ratios, which are mainly used in our discussions.

By assuming that the abundance of the A state is the same as that of the E state, the total beam-averaged column density of CH$_3$OH for each source is determined from the integrated intensities within the velocity range of the C$_2$H line averaged for the four hyperfine components in order to eliminate the outflow component as much as possible. Since the actual source size is unknown for most of the sources, the beam filling factor of unity is used for simplicity, as discussed above. Thus, the beam-averaged column density is derived in this study. Here, the uncertainties of the derived column densities are evaluated from the rms noise. For C$_2$H and c-C$_3$H$_2$, we used the *N* = 3–2, *J* = 5/2–3/2, *F* = 3–2 line and the 3$_{2,1}$–2$_{1,2}$ line to derive the beam-averaged column density, respectively, where we assume the rotation

<footnote>a Obtained by the Gaussian fit.</footnote>

<footnote>b The rms noise averaged over the line width.</footnote>
<figure><img src="image_5.png" /><figcaption>**Figure 2.** Line profiles of CH$_{3}$OH (J = 5–4) observed with IRAM 30 m. The spectra taken with the wobbler switching are indicated with an asterisk (ASAI project). (An extended version of this figure is available.)</figcaption></figure>
<figure><img src="image_6.png" /><figcaption>**Figure 3.** Line profiles of C₂H (N = 3–2) observed with IRAM 30 m. The spectra taken with the wobbler switching are indicated with an asterisk (ASAI project). (An extended version of this figure is available.)</figcaption></figure>
<figure><img src="image_7.png" /><figcaption>**Figure 4.** Line profiles of c-C$_3$H$_2$ (3$_{2,1}$–2$_{1,2}$) observed with IRAM 30 m. The spectra taken with the wobbler switching are indicated with an asterisk (ASAI project). (An extended version of this figure is available.)</figcaption></figure>
<figure><img src="image_8.png" /><figcaption>**Figure 5.** (a) Correlation plot between the integrated intensities of the C₂H (N = 3–2, J = 5/2–3/2, F = 3–2) and CH₃OH (J = 5–4, K = 1, E⁻) lines, excluding wing components for the latter (correlation coefficient = 0.04). The dashed lines indicate the intensity ratios of 100, 10, 1, 0.1, and 0.01. (b) Correlation plot between the integrated intensities of the C₂H (N = 3–2, J = 5/2–3/2, F = 3–2) and CH₃OH (J = 5–4, K = 1, E⁻) lines, including the wing components for the latter (correlation coefficient = 0.04). The dashed lines indicate the intensity ratios of 100, 10, 1, 0.1, and 0.01. (c) Correlation plot between the integrated intensities of the c-C₃H₂ (3₂,₁–2₁,₂) and CH₃OH (J = 5–4, K = 1, E⁻) lines (correlation coefficient = 0.17). The dashed lines indicate the intensity ratios of 100, 10, 1, 0.1, and 0.01. (d) Correlation plot between the integrated intensities of the C₂H (N = 3–2, J = 5/2–3/2, F = 3–2) and c-C₃H₂ (3₂,₁–2₁,₂) lines (correlation coefficient = 0.75). The dashed lines indicate the intensity ratios of 100, 10, 1, 0.1, and 0.01. Data points with an arrow in CH₃OH and c-C₃H₂ intensities show the upper limits. The correlation coefficient is defined as $\Sigma(x_i - \bar{x})(y_i - \bar{y}) / \sqrt{\Sigma(x_i - \bar{x})^2 \Sigma(y_i - \bar{y})^2}$, where x̄ and ȳ represent the average values of the data xᵢ and yᵢ, respectively.</figcaption></figure>

temperature of CH₃OH derived for each source. Note that for NGC 1333-16 and NGC 1333-17, the rotation temperatures of CH₃OH for the nearby sources, NGC 1333-1 and NGC 1333-2, are employed, respectively, because of the lack of the Nobeyama data. Table 3 summarizes the derived beam-averaged column densities.

NGC 1333-1 (IRAS 4B), NGC 1333-16 (IRAS 4A), NGC 1333-7, and B1-3 show high CH₃OH column densities. On the other hand, L1448-2 shows higher column densities of C₂H and c-C₃H₂, which are about an order of magnitude higher than those in NGC 1333-1, and about a half an order of magnitude higher than those in L1527 (Sakai et al. 2008).

# 4. Discussion

## 4.1. Chemical Variation between C₂H and CH₃OH

In this section, we use the beam-averaged column densities summarized in Table 3 to characterize the chemical composition of

protostellar sources at a few 1000 au scale. Smaller-scale chemical variation is averaged out, and hence a spatial attention is needed when they are compared with the column densities in other studies at a higher angular resolution or with source-size corrections. Nevertheless, the beam-averaged column densities can be used for mutual comparison among our samples in the Perseus molecular cloud complex, because the sources are at similar distances and the column densities are derived in a uniform way.

Figure 8(a) shows the correlation plot of the beam-averaged column densities between C₂H and CH₃OH, while Figure 8(b) depicts those between C₂H and c-C₃H₂. The column densities of C₂H and c-C₃H₂ correlate with each other, because these two molecules would be produced in related pathways (Sakai & Yamamoto 2013). In contrast, no correlation can be seen between C₂H and CH₃OH in the column densities, similar to the integrated intensities (Figures 5(a) and (b)). Similarly, no correlation is found between c-C₃H₂ and CH₃OH, either, as shown in Figure 5(c).
<figure><img src="image_9.png" /><figcaption>**Figure 6.** Rotation diagrams of CH<sub>3</sub>OH for NGC 1333-1, NGC 1333-6, B1-3, B1-5, and L1448-3.</figcaption></figure>

These results clearly indicate the chemical diversity at a few 1000 au scale around the protostar. The C<sub>2</sub>H/CH<sub>3</sub>OH ratios range over almost two orders of magnitude even among the Class 0/I sources within the same molecular cloud complex. A similar diversity for the C<sub>4</sub>H/CH<sub>3</sub>OH ratio among various protostellar sources was also reported by Graninger et al. (2016) and Lindberg et al. (2016). However, our result is the first one based on unbiased samples in the single molecular cloud complex.

It is likely that the above chemical diversity at a few 1000 au scale is related to the chemical diversity identified at a smaller scale; namely, hot corino chemistry and WCCC. As discussed by Sakai et al. (2009) and Sakai & Yamamoto (2013), definitive identification of hot corino chemistry and WCCC requires the confirmation of the central concentration

of COMs and carbon-chain molecules, respectively. Such a concentration is not confirmed for C<sub>2</sub>H, C-C<sub>3</sub>H<sub>2</sub>, and CH<sub>3</sub>OH in our single-point observations. Nevertheless, it is likely that the beam-averaged chemical composition does reflect the chemical composition of the protostellar core to some extent, because the high excitation lines of CH<sub>3</sub>OH, C<sub>2</sub>H, and C-C<sub>3</sub>H<sub>2</sub> are employed in this study to trace dense regions rather than the component extended over parent molecular clouds.

For NGC 1333-1 (IRAS 4B) and NGC 1333-16 (IRAS 4A), which have previously been identified as hot corino sources, we indeed see abundant CH<sub>3</sub>OH but deficient C<sub>2</sub>H, their C<sub>2</sub>H/CH<sub>3</sub>OH column density ratios being almost the lowest among the observed sources (Table 3). On the other hand, the WCCC source L1527 in Taurus, which is employed as a
<figure><img src="image_10.png" /><figcaption>**Figure 7.** Correlation plot between the integrated intensities of CH<sub>3</sub>OH (J = 5–4, K = 1, E<sup>-</sup>) lines, excluding wing components and the protostellar luminosity (correlation coefficient = 0.19). The data point with an arrowed line in the CH<sub>3</sub>OH intensity shows the upper limit. The correlation coefficient is defined in the caption in Figure 5.</figcaption></figure>

reference, shows abundant C<sub>2</sub>H and deficient CH<sub>3</sub>OH with the single-dish observation in the ASAI project (Lefloch et al. 2018), as shown in Figure 9(a). Importantly, most of the sources show the ratios between those of the hot corino sources and the WCCC source. Thus, the hot corino sources and the WCCC source are certainly two extreme cases of chemical variation.

Sakai et al. (2009) and Sakai & Yamamoto (2013) suggested that the difference in the chemical compositions found between WCCC sources and hot corino sources could originate from the different duration times of the starless phase after shielding the interstellar UV radiation in the parent molecular cloud. For efficient formation of various COMs, a significant amount of CH<sub>3</sub>OH is necessary as a parent molecule (e.g., Garrod & Herbst 2006). CH<sub>3</sub>OH is mainly formed by hydrogenation of CO on a grain mantle (e.g., Tielens & Hagen 1982; Watanabe & Kouchi 2002; Soma et al. 2015). On the other hand, it takes about 10<sup>5</sup>-6 years for the formation of CH<sub>3</sub>OH from CO, if the H<sub>2</sub> density of the parent cloud is as high as 10<sup>5</sup> cm<sup>-3</sup> (Taquet et al. 2012). When the core-collapse starts well after the shielding of the interstellar UV radiation in the parent cloud, most of the carbon atoms are fixed into CO by gas-phase reactions, and CO is depleted onto dust grains in dense and cold regions to form CH<sub>3</sub>OH.

On the other hand, there is not enough time for the C to CO conversion in the gas-phase, if the core-collapse starts just after the UV-shielding. Carbon atoms can still be abundant in such cores. The timescale for the depletion of atoms and molecules onto dust grains is roughly 10<sup>5</sup>/(n/10<sup>4</sup> cm<sup>-3</sup>) yr (e.g., Burke & Hollenbach 1983), which is comparable to the dynamical timescale. Hence, carbon atom is depleted onto dust grains before it is converted to CO by gas-phase reactions. Hydrogenation of C on grain surfaces forms CH<sub>4</sub> efficiently. After the onset of star formation, CH<sub>4</sub> is evaporated into the gas-phase in a warm region (T > 25 K) to form various carbon-chain molecules through gas-phase reactions (i.e., the WCCC mechanism). In this case, the core-collapse occurs in chemically young clouds, hence carbon-chain molecules

produced in the early evolutionary stage of cold starless cores could also survive in the gas-phase to some extent.

In L1527, a cold envelope with abundant carbon-chain molecules surrounds the dense (n ~ 10<sup>6</sup> cm<sup>-3</sup>) and warm (T > 25 K) core where the enhancement of carbon-chain molecules due to WCCC is occurring (Sakai et al. 2010). In contrast, carbon-chain molecules are relatively deficient in hot corino sources even in the surrounding component (e.g., Sakai & Yamamoto 2013). Therefore, the ratios between carbon-chain molecules, especially C<sub>n</sub>H and C<sub>n</sub>H<sub>2</sub>, and CH<sub>3</sub>OH, are expected to represent the chemical characteristics of protostellar cores, even if a part of the observed emission comes from outflows or cold dense envelopes in addition to that from the inner part of protostellar cores.

It should be noted that C<sub>2</sub>H is known to be abundant in PDRs (e.g., Pety et al. 2007; Cuadrado et al. 2015). In such regions, C<sub>2</sub>H is efficiently produced from C<sup>+</sup> in the gas-phase reaction and/or is formed by destruction of very small grains and polycyclic aromatic hydrocarbons (e.g., Cuadrado et al. 2015). However, we observed the regions with high extinction (A<sub>v</sub> > 5–7 mag; Kirk et al. 2006) in relatively high critical density lines. Hence, the detected C<sub>2</sub>H emissions would mainly originate from protostellar cores rather than to the surrounding diffuse parts to which the UV radiation can penetrate. Nevertheless, C<sub>2</sub>H would also exist in the cavity walls of low-velocity outflows, where C<sub>2</sub>H could be formed by the UV radiation from the central protostar (e.g., Oya et al. 2014). To assess this effect, we also observed the c-C<sub>3</sub>H<sub>2</sub> lines. As demonstrated in Figure 8(b), the column densities of C<sub>2</sub>H and c-C<sub>3</sub>H<sub>2</sub> show a good correlation. The C<sub>2</sub>H/c-C<sub>3</sub>H<sub>2</sub> ratio is about 10, which is lower than those found in PDRs and diffuse clouds and is rather close to those of dense cores (Gerin et al. 2011; Cuadrado et al. 2015). In fact, Lindberg et al. (2015) also reported that c-C<sub>3</sub>H<sub>2</sub> is not affected by the UV radiation in the R CrA region. Although c-C<sub>3</sub>H<sub>2</sub> is detected in the outflow-shocked region L1157 B1 (Yamaguchi et al. 2012), its abundance is not as high as that in the protostellar core of L1157 mm (Bachiller & Pérez Gutiérrez 1997). Above all, the diversity seen in the C<sub>2</sub>H/CH<sub>3</sub>OH column density ratio most likely reflects the chemical diversity of protostellar cores.

## 4.2. Effects from the Evolutionary Stage of the Source

Figures 9(a)–(c) show the correlation plots of the C<sub>2</sub>H/CH<sub>3</sub>OH ratio against the envelope mass M<sub>env</sub>, the ratio of the bolometric luminosity to the submillimeter wavelength luminosity L<sub>bol</sub>/L<sub>smm</sub>, and the bolometric temperature T<sub>bol</sub>, respectively. The envelope mass (M<sub>env</sub>) represents the amount of the gas associated with the protostar, whereas L<sub>bol</sub>/L<sub>smm</sub> and T<sub>bol</sub> are known as evolutionary indicators of the protostellar source (Hatchell et al. 2005, 2007).

In Figure 9(a), the M<sub>env</sub> values are taken from Hatchell et al. (2007). These values are derived from the 850 µm dust continuum flux observed with JCMT, which has a beam size similar to that of our IRAM 30 m observations in the 1.3 mm band (~15′′). The correlation coefficient is 0.02, indicating no correlation. Hence, the result indicates that there is no clear relationship between the chemical composition and the mass to be accreted.

Likewise, L<sub>bol</sub>/L<sub>smm</sub> and T<sub>bol</sub> also do not show a correlation with the C<sub>2</sub>H/CH<sub>3</sub>OH ratio (Figures 9(b) and (c)), where L<sub>bol</sub>/L<sub>smm</sub> and T<sub>bol</sub> are also taken from Hatchell et al. (2007).
<figure><img src="image_11.png" /><figcaption>**Figure 8.** (a) Correlation plot between the column densities of C<sub>2</sub>H and CH<sub>3</sub>OH (correlation coefficient = 0.01). The dashed lines indicate intensity ratios of 100, 10, 1, and 0.1. (b) Correlation plot between the column densities of C<sub>2</sub>H and C-C<sub>3</sub>H<sub>2</sub> (correlation coefficient = 0.88). The dashed lines indicate intensity ratios of 100, 10, 1, and 0.1. (c) Correlation plot between the column densities of C-C<sub>3</sub>H<sub>2</sub> and CH<sub>3</sub>OH (correlation coefficient = 0.1). The dashed lines indicate intensity ratios of 100, 10, 1, and 0.1. Data points with an arrow in CH<sub>3</sub>OH and C-C<sub>3</sub>H<sub>2</sub> column densities show the upper limits. The correlation coefficient is defined in the caption in Figure 5.</figcaption></figure>

The correlation coefficients for the L<sub>bol</sub>/L<sub>smm</sub> and T<sub>bol</sub> plots are as small as 0.26 and 0.31, respectively. Thus, the evolutionary stage does not show correlation with the C<sub>2</sub>H/CH<sub>3</sub>OH ratio. This is because the chemical composition of the grain mantles, which characterizes the gas-phase chemical composition after the onset of star formation, has already been determined by the processes during the starless core phase.

### 4.3. Positional Effects in the Parent Cloud

To test the relation between the positions of protostars and the C<sub>2</sub>H/CH<sub>3</sub>OH ratios, we introduce the minimum projected distance from the molecular cloud edge, D<sub>min</sub>, i.e., small D<sub>min</sub> indicates a source closer to the edge of the cloud. D<sub>min</sub> is calculated using the Planck 217 GHz continuum map (see Figure 10), where the cloud edge is arbitrarily defined as the 10σ contour. Note that the 10σ contour of the Planck continuum map, which we employ as the edge of the cloud, corresponds to an A<sub>v</sub> of 1 mag (Kirk et al. 2006). Figure 9(d) shows the correlation plot of the C<sub>2</sub>H/CH<sub>3</sub>OH ratio against D<sub>min</sub>. Note that a typical size of the cloud is 1 pc

(e.g., Hacar et al. 2017), hence there is a sharp limit of D<sub>min</sub> around 0.6–0.7 pc.

D<sub>min</sub> is a projected distance, and the line-of-sight depth from the cloud surface is unknown. Hence, sources that appear near the center of the cloud are not always embedded deeply in the clouds, but some of them may be close to the cloud periphery along the line of sight. Although D<sub>min</sub> is affected by this projection effect, we can obtain clues regarding the origin of the chemical diversity from Figure 9(d). These results suggest that the sources with lower ratios tend to appear only at larger D<sub>min</sub>. Namely, they are likely more embedded in the central part of the large molecular clouds.

Figure 9(d) shows a kind of “right angle” distribution of the points: sources with small D<sub>min</sub> have only high C<sub>2</sub>H/CH<sub>3</sub>OH ratios. On the other hand, sources with large D<sub>min</sub> have both high and low C<sub>2</sub>H/CH<sub>3</sub>OH ratios, indicating a large scatter of the ratios. Although this scatter mainly comes from the NGC 1333 region, a similar trend can be seen in the plots without the NGC 1333 sources. It should be stressed that there is a blank area in the bottom left corner, where D<sub>min</sub> is small and the ratio is low.
<figure><img src="image_12.png" /><figcaption>**Figure 9.** Correlation plot between the C~2~H/CH~3~OH ratio vs. (a) envelope mass M~env~(correlation coefficient = 0.02), (b) L~bol~/L~smm~ (correlation coefficient = 0.26), (c) T~bol~ (correlation coefficient = 0.31), (d) D~min~, the minimum distance from the source position and cloud edge (correlation coefficient = 0.27), and (e) the peak intensity of the source position from the Planck map (correlation coefficient = 0.42). A dashed line of 0.1 pc shows the spatial resolution of the observations, and the line of 1 pc shows the largest cloud size for (d). Data points with an arrow show the lower limits. The correlation coefficient is defined in the caption in Figure 5. The correlation coefficient is derived excluding the lower limit data. If we include the data point, the correlation coefficient changes to 0.12 for (a), 0.13 for (b), 0.28 for (c), 0.45 for (d), and 0.58 for (e), respectively.</figcaption></figure>
<figure><img src="image_13.png" /><figcaption>**Figure 10.** Planck 217 GHz map (central part; contours are 5σ, 10σ, 15σ, 20σ, 25σ, 30σ, 35σ, and 40σ levels, 1σ = 0.5 mK) and SCUBA 850 µm maps of the NGC 1333, L1448, IC 348, B5, B1, and L1455 regions. The grayscale is a 850 µm continuum. The flux is shown on a log scale from 0.5 Jy beam⁻¹ to 1.5 Jy beam⁻¹. Contours are 5σ, 10σ, 20σ, 40σ, 60σ, 80σ, 100σ, 200σ, and 400σ levels (1σ = 0.01 Jy beam⁻¹). The radius of each circle overlaid on the JCMT 850 µm images of the Perseus clouds (Chen et al. 2016) is proportional to the C₂H/CH₃OH ratio. The colors show the systemic velocity of the individual position.</figcaption></figure>

One may think that this is caused by the source selection effect. In our source sample, the very-low-luminosity ($L_{bol} < 1 L_{⊙}$) sources are missing. If these sources had a low C₂H/CH₃OH ratio, the blank area might be filled up. However, this would not be the case, because there is no correlation between the luminosity and the C₂H/CH₃OH ratio.

Most of the chemical diversity in our sample is thus concentrated in the large $D_{min}$ region. Since all the sources near the cloud edge (small $D_{min}$ sources) have high ratios, the sources with high ratios at large $D_{min}$ may have a small line-of-sight depth from the cloud surface. Alternatively, substructure (clumpy and/or filamentary structure) in the molecular clouds (e.g., velocity-coherent structures found in NGC 1333 by Hacar et al. 2017) might also contribute to the high ratios because such substructures allow the interstellar UV radiation to penetrate into the cloud (e.g., Stutzki et al. 1988; Meixner & Tielens 1993).

In order to investigate the relation between the C₂H/CH₃OH ratio and the line-of sight depth of the cloud, we prepare the correlation of the ratio against the peak intensity of the Planck continuum map at the source positions, as shown in Figure 9(e). The distribution of the points reveals a trend similar to that found in Figure 9(d). Again, there is a blank area in the bottom left corner, where the peak intensity is low and the ratio is low. The scatter in the high peak intensity region can be interpreted in the same way as that in the large $D_{min}$ case.

In Figure 10, the C₂H/CH₃OH ratio is represented by a radius of the circle, which is overlaid on the JCMT 850 µm images of the Perseus clouds (Chen et al. 2016). Indeed, the high C₂H/CH₃OH ratio sources, i.e., the WCCC-type sources (larger circles), seem to be isolated or located at the edge of the cloud, although NGC 1333-17 (SVS 13A) is an exception. In contrast, the low C₂H/CH₃OH ratio sources, i.e., sources whose chemical character is close to the hot corino sources, tend to be concentrated in the inner regions of the cluster-forming clouds (NGC 1333 and IC 348). This result implies that the isolated sources and the sources in cloud peripheries tend to have the WCCC character in the Perseus molecular cloud complex.

In the central part of the cloud, the time after the UV-shielding would be longer than that in the cloud peripheries, because the surrounding gas gradually contracting to the main body of the cloud can shield the UV radiation. In the cloud center, the carbon atoms have been converted to CO, and CO depletion has already occurred in dense cores. In this case, CH₃OH can be abundant on dust grains, which is reflected in the gas-phase abundance through the thermal and/or non-thermal desorption processes. On the other hand, carbon atoms can be abundant in the cloud peripheries. They can be depleted directly onto dust grains to form CH₄, which leads to WCCC. This picture is consistent with the result in which higher C₂H/CH₃OH and C₃H₂/CH₃OH ratios are seen in protostellar cores at the cloud peripheries,
<figure><img src="image_14.png" /><figcaption>**Figure 11.** Rotation diagrams of CH$_3$OH (E state). Detected lines are marked by points with error bars. A solid line indicates a single temperature fit. (An extended version of this figure is available.)</figcaption></figure>
whereas low values only appear in the cores at the cloud center.

However, it is not clear at present whether the regeneration mechanism of carbon-chain molecules expected for WCCC is actually occurring in the sources with the high C₂H/CH₃OH and c-C₃H₂/CH₃OH ratios. To assess this point, the central concentration of carbon-chain molecules should be confirmed for each source by high-resolution observations. Moreover, it has recently been revealed that the situation may be more complicated at a smaller scale (<100 au). For instance, the isolated Bok globule B335 shows WCCC in the outer envelope (~1000 au), while it harbors a hot corino in the central 10 au region (Imai et al. 2016). A similar structure can also be seen in L483 (Oya et al. 2017). Therefore, it is not obvious whether the high ratios observed at a 1000 au scale are brought onto a smaller scale (<100 au), as they are. On the other hand, the WCCC sources L1527 and TMC-1A indeed show faint emission of CH₃OH even at a 100 au scale. Although the chemical composition at a 1000 au scale likely affects that at a smaller scale to some extent, high-resolution observations are essential to confirm the situation for each source.

## 5. Conclusions

We present the results of an unbiased survey of the chemical composition toward the 36 Class 0 and Class I protostars in the Perseus molecular cloud complex. The results are summarized as follows:

1. Multiple transition lines of C₂H, c-C₃H₂, and CH₃OH were detected toward most of the target sources. The CH₃OH (J = 5–4) lines were detected toward 35 sources, the CH₃OH (J = 2–1) and the C₂H (N = 3–2) lines toward all the sources, and the c-C₃H₂ (3₂,₁–2₁,₂) lines toward 30 sources.

2. A correlation plot between the integrated intensities of the C₂H and CH₃OH lines is prepared for the two cases with and without the wing components. In both cases, no correlation is seen between them. Similarly, no correlation is found between the integrated intensities of the c-C₃H₂ and CH₃OH lines. In contrast, the integrated intensities of the C₂H and c-C₃H₂ lines show a positive correlation, because these two species are thought to be produced through related chemical pathways.

3. The column density ratios of C₂H/CH₃OH show a significant diversity by 2 orders of magnitude. The hot corino sources show the highest ratio, while the WCCC source L1527, employed as a reference, shows the lowest ratio. The ratios of most sources are in between these two distinct cases.

4. The C₂H/CH₃OH ratio does not correlate with the evolutionary indicators (Lₜbol/Lₜsmm and Tₜbol), nor the envelope mass. On the other hand, we find that the isolated sources and the sources located in cloud peripheries tend to have chemical characteristics of WCCC (i.e., high C₂H/CH₃OH ratios). In the Perseus molecular cloud complex, the hot-corino-like sources (i.e., low C₂H/CH₃OH ratios) do not exist in such regions, but are concentrated in the central parts of the cluster-forming regions. This result is qualitatively consistent with the idea that the chemical diversity would originate from the different duration times of the starless core phase after the shielding of the interstellar UV radiation.

5. It is important to study, with high angular resolution observations, whether the chemical composition seen in this study is brought into inner-envelope/disk systems for each source.

We thank the referee for the thoughtful and constructive comments. We are grateful to the staff of NRO and IRAM for excellent support of our observations. This study is supported by KAKENHI (25108005 and 16H03964). The authors also acknowledge financial support by JSPS and MAEE under the Japan-France integrated action programme.

Software: NEWSTAR, GILDAS.

## ORCID iDs

Aya E. Higuchi https://orcid.org/0000-0002-9221-2910

Nami Sakai https://orcid.org/0000-0002-3297-4497

Yoshimasa Watanabe https://orcid.org/0000-0002-9668-3592

Yoko Oya https://orcid.org/0000-0002-0197-8751

Muneaki Imai https://orcid.org/0000-0002-5342-6262

Yichen Zhang https://orcid.org/0000-0001-7511-0034

Cecilia Ceccarelli https://orcid.org/0000-0001-9664-6292

Claudio Codella https://orcid.org/0000-0003-1514-3074

Rafael Bachiller https://orcid.org/0000-0002-5331-5386

Tomoya Hirota https://orcid.org/0000-0003-1659-095X

Takeshi Sakai https://orcid.org/0000-0003-4521-7492

## References

Bachiller, R., Codella, C., Colomer, F., Liechti, S., & Walmsley, C. M. 1998, A&A, 335, 266

Bachiller, R., & Pérez Gutiérrez, M. 1997, ApJL, 487, L93

Bizzocchi, L., Caselli, P., Spezzano, S., & Leonardo, E. 2014, A&A, 569, A27

Bottinelli, S., Ceccarelli, C., Neri, R., et al. 2004, ApJL, 617, L69

Buckle, J. V., & Fuller, G. A. 2002, A&A, 381, 77

Burke, J. R., & Hollenbach, D. J. 1983, ApJ, 265, 223

Cazaux, S., Tielens, A. G. G. M., Ceccarelli, C., et al. 2003, ApJL, 593, L51

Chen, M. C.-Y., Di Francesco, J., Johnstone, D., et al. 2016, ApJ, 826, 95

Codella, C., Ceccarelli, C., Cabrit, S., et al. 2016, A&A, 586, L3

Cuadrado, S., Goicoechea, J. R., Pilleri, P., et al. 2015, A&A, 575, A82

Fontani, F., Palau, A., Busquet, G., et al. 2012, MNRAS, 423, 1691

Fukui, Y., Harada, R., Tokuda, K., et al. 2015, ApJL, 807, L4

Garrod, R. T., & Herbst, E. 2006, A&A, 457, 927

Gerin, M., Kaźmierczak, M., Jastrzebska, M., et al. 2011, A&A, 525, A116

Graninger, D. M., Wilkins, O. H., & Öberg, K. I. 2016, ApJ, 819, 140

Guzmán, V., Pety, J., Gratier, P., et al. 2015, HiA, 16, 593

Hacar, A., Tafalla, M., & Alves, J. 2017, A&A, 606, A123

Hatchell, J., Fuller, G. A., Richer, J. S., Harries, T. J., & Ladd, E. F. 2007, A&A, 468, 1009

Hatchell, J., Richer, J. S., Fuller, G. A., et al. 2005, A&A, 440, 151

Higuchi, A. E., Chibueze, J. O., Habe, A., Takahira, K., & Takano, S. 2014, AJ, 147, 141

Higuchi, A. E., Kurono, Y., Saito, M., & Kawabe, R. 2010, ApJ, 719, 1813

Hirota, T., Bushimata, T., Choi, Y. K., et al. 2008, PASJ, 60, 37

Hirota, T., Honma, M., Imai, H., et al. 2011, PASJ, 63, 1

Imai, M., Sakai, N., Oya, Y., et al. 2016, ApJL, 830, L37

Jørgensen, J. K., Harvey, P. M., Evans, N. J., et al. 2006, ApJ, 645, 1246

Kirk, H., Johnstone, D., & Di Francesco, J. 2006, ApJ, 646, 1009

Koumpia, E., Semenov, D. A., van der Tak, F. F. S., Boogert, A. C. A., & Caux, E. 2017, A&A, 603, A88

Koumpia, E., van der Tak, F. F. S., Kwon, W., et al. 2016, A&A, 595, A51

Kristensen, L. E., van Dishoeck, E. F., van Kempen, T. A., et al. 2010, A&A, 516, A57

Lefloch, B., Bachiller, R., Ceccarelli, C., et al. 2018, MNRAS, 477, 4792

Lindberg, J. E., Charnley, S. B., & Cordiner, M. A. 2016, ApJL, 833, L14

Lindberg, J. E., & Jørgensen, J. K. 2012, A&A, 548, A24

Lindberg, J. E., Jørgensen, J. K., Watanabe, Y., et al. 2015, A&A, 584, A28

Maret, S., Ceccarelli, C., Tielens, A. G. G. M., et al. 2005, A&A, 442, 527

Meixner, M., & Tielens, A. G. G. M. 1993, ApJ, 405, 216
Öberg, K. I., van der Marel, N., Kristensen, L. E., & van Dishoeck, E. F. 2011, ApJ, 740, 14

Oya, Y., Sakai, N., Sakai, T., et al. 2014, ApJ, 795, 152

Oya, Y., Sakai, N., Watanabe, Y., et al. 2017, ApJ, 837, 174

Pety, J., Goicoechea, J. R., Hily-Blant, P., Gerin, M., & Teyssier, D. 2007, A&A, 464, L41

Sakai, N., Ceccarelli, C., Bottinelli, S., Sakai, T., & Yamamoto, S. 2012, ApJ, 754, 70

Sakai, N., Oya, Y., Sakai, T., et al. 2014a, ApJL, 791, L38

Sakai, N., Sakai, T., Hirota, T., et al. 2014b, Natur, 507, 78

Sakai, N., Sakai, T., Hirota, T., Burton, M., & Yamamoto, S. 2009, ApJ, 697, 769

Sakai, N., Sakai, T., Hirota, T., & Yamamoto, S. 2008, ApJ, 672, 371

Sakai, N., Sakai, T., Hirota, T., & Yamamoto, S. 2010, ApJ, 722, 1633

Sakai, N., Sakai, T., & Yamamoto, S. 2006, PASJ, 58, L15

Sakai, N., & Yamamoto, S. 2013, ChRv, 113, 8981

Saruwatari, O., Sakai, N., Liu, S.-Y., et al. 2011, ApJ, 729, 147

Soma, T., Sakai, N., Watanabe, Y., & Yamamoto, S. 2015, ApJ, 802, 74

Spezzano, S., Bizzocchi, S., Caselli, P., Harju, J., & Brünken, S. 2016a, A&A, 592, L11

Spezzano, S., Gupta, H., Brünken, S., et al. 2016b, A&A, 586, A110

Stutzki, J., Stacey, G. J., Genzel, R., et al. 1988, ApJ, 332, 379

Takakuwa, S., Mikami, H., Saito, M., & Hirano, N. 2000, ApJ, 542, 367

Taquet, V., Ceccarelli, C., & Kahane, C. 2012, A&A, 538, A42

Tielens, A. G. G. M., & Hagen, W. 1982, A&A, 114, 245

Watanabe, N., & Kouchi, A. 2002, ApJL, 571, L173

Watanabe, Y., Sakai, N., Lindberg, J. E., et al. 2012, ApJ, 745, 126

Watanabe, Y., Sakai, N., López-Sepulcre, A., et al. 2015, ApJ, 809, 162

Yamaguchi, T., Takano, S., Watanabe, Y., et al. 2012, PASJ, 64, 105

Yoshida, K., Sakai, N., Tokudome, T., et al. 2015, ApJ, 807, 66

Yamamoto, S. 2017, Introduction to Astrochemistry: Chemical Evolution from Interstellar Clouds to Star and Planet Formation (Tokyo: Springer Japan)