bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Suzaku Discovery of A Hard Power-Law Component in the Spectra of Short Bursts from SGR 0501+4516
Authors: Nakagawa Yujin E. , Makishima Kazuo , Enoto Teruaki 
Published: March 2014

Abstract
Using data with the Suzaku XIS and HXD, spectral studies of short bursts from the soft gamma repeater SGR 0501 $+$ 4516 were performed. In total, 32 bursts were detected during the $\sim\ $ 60 ks of observation conducted in the 2008 August activity. Excluding the strongest one, the remaining 31 bursts showed an average 2–40 keV fluence of $\left(1.0_{-0.5}^{+0.3}\right)$$\times$ 10 $^{-9}\ $ erg cm $^{-2}$ . A 1–40 keV spectrum summed over them leaves significant positive residuals in the HXD-PIN band with $\chi^{2}/$ d.o.f. $=$ 74 $/$ 50, when fitted with a two-blackbody function. By adding a power-law model, the fit became acceptable with $\chi^2/$ d.o.f. $=$ 56 $/$ 48, yielding a photon index of $\Gamma$$=$ 1.0 $_{-0.3}^{+0.4}$ . This photon index is comparable to $\Gamma$$=$ 1.33 $_{-0.16}^{+0.23}$ (Enoto et al. 2010, ApJ, 715, 665) for the persistent emission of the same object obtained with Suzaku. The two-blackbody components showed very similar ratios, both in the temperature and the emission radii, to those comprising the persistent emission. However, the power-law to two-blackbody flux ratio was possibly higher than that of the persistent emission at the 2.6 $\ \sigma$ level. Based on these measurements, average wide-band properties of these relatively weak bursts are compared with those of the persistent emission.
Suzaku View of the Supernova Remnant RCW 86: X-Ray Studies of Newly-Discovered Fe-Rich Ejecta
Authors: Yamaguchi Hiroya , Koyama Katsuji , Uchida Hiroyuki 
Published: March 2014

Abstract
We report on results of imaging and spectral analysis of the supernova remnant (SNR) RCW 86 observed with Suzaku. The SNR is known to exhibit K-shell emission of low ionized Fe, possibly originating from supernova ejecta. We revealed the global distribution of the Fe-rich plasma in the entire remnant, for the first time; the Fe-K emission was clearly detected from the west, north, and south regions, in addition to the X-ray brighter shells of southwest and northeast, where the presence of the Fe-rich ejecta has already been reported. The spectrum of each region is well represented by a three-component model consisting of low- and high-temperature thermal plasmas and non-thermal emission. The lower-temperature component, with elemental abundances of near the solar values, likely originates from the forward shocked interstellar medium, while the Fe-rich ejecta is described by the hotter plasma. From the morphologies of the forward and reverse shocks in the west region, the total ejecta mass is estimated to be 1–2 $\ M_{\odot}$ for the typical explosion energy of $\sim\ $ 1 $\times$ 10 $^{51}\ $ erg. The integrated flux of the Fe-K emission from the entire SNR roughly corresponds to a total Fe mass of about 1 $\ M_{\odot}$ . Both of these estimates suggest a Type Ia supernova origin of this SNR. We also find possible evidence of an Fe-rich clump located beyond the forward-shock front in the north rim, which is reminiscent of ejecta knots observed in the Tycho and Vela SNRs.
Suzaku and XMM-Newton Observations of the Fornax Cluster: Temperature and Metallicity Distribution
Authors: Murakami Hideyoshi , Komiyama Madoka , Matsushita Kyoko , Nagino Ryo , Sato Takuya , Sato Kosuke , Kawaharada Madoka , Nakazawa Kazuhiro , Ohashi Takaya , Takei Yoh 
Published: March 2014

Abstract
Suzaku observed a central region and five offset regions within 0.2 $\ r_{180}$ in the Fornax cluster, a nearby poor cluster, and XMM-Newton mapped the cluster with 15 pointings out to 0.3 $\ r_{180}$ . The distributions of O, Mg, Si, S, and Fe in the intracluster medium (ICM) were studied with Suzaku, and those of Fe and temperature were studied with XMM. The temperature of the ICM gradually decreases with the radius from 1.3 keV at 0.04 $\ r_{180}$ to 1 keV at 0.2–0.3 $\ r_{180}$ . If the new solar abundances of Lodders et al. (2003), ApJ, 591, 1220) and a single-temperature plasma model are adopted, O, Mg, Si, S, and Fe show similar abundances: 0.4–0.6 solar within 0.02–0.2 $\ r_{180}$ . This Fe abundance is similar to those at 0.1–0.2 $\ r_{180}$ in rich clusters and other groups of galaxies. At 0.2–0.3 $\ r_{180}$ , the Fe abundance becomes 0.2–0.3 solar. A two-temperature plasma model yields ICM abundances that are higher by a factor of 1.2–1.5, but give similar abundance ratios among O, Mg, Si, S, and Fe. The northern region has a lower ICM temperature and higher brightness and Fe abundance, whereas the southern region has a higher ICM temperature and lower brightness and Fe abundance. These results indicate that the cD galaxy may have traveled from the north because of recent dynamical evolution. The cumulative oxygen- and iron-mass-to-light ratios (OMLR and IMLR) within 0.3 $\ r_{180}$ are an order of magnitude lower than those of rich clusters and some relaxed groups of galaxies. Past dynamical evolution might have hindered the strong concentration of hot gas in the Fornax cluster's central region. Scatter in the IMLR and similarity in the element abundances in the ICM of groups and clusters of galaxies indicate early metal synthesis.
13CO(J = 1–0) On-the-Fly Mapping of the Giant H II Region NGC 604: Variation in Molecular Gas Density and Temperature due to Sequential Star Formation
Authors: Muraoka Kazuyuki , Tosaki Tomoka , Miura Rie , Onodera Sachiko , Kuno Nario , Nakanishi Kouichiro , Kaneko Hiroyuki , Komugi Shinya 
Published: March 2014

Abstract
We present $^{13}$CO($J$$=$ 1–0) line emission observations with the Nobeyama 45-m telescope toward the giant H II region NGC 604 in the spiral galaxy M 33. We detected $^{13}$CO($J$$=$ 1–0) line emissions in 3 major giant molecular clouds (GMCs) labeled as GMC-A, B, and C beginning at the north. We derived two line intensity ratios, $^{13}$CO($J$$=$ 1–0)$/$$^{12}$CO($J$$=$ 1–0), $R_{13/12}$, and $^{12}$CO($J$$=$ 3–2)$/$$^{12}$CO($J$$=$ 1–0), $R_{31}$, for each GMC at an angular resolution of 25$”$ (100 pc). The averaged values of $R_{13/12}$ and $R_{31}$ are 0.06 and 0.31 within the whole GMC-A, 0.11 and 0.67 within the whole GMC-B, and 0.05 and 0.36 within the whole GMC-C, respectively. In addition, we obtained $R_{13/12}$$=$ 0.09$\ \pm\ $0.02 and $R_{31}$$=$ 0.76$\ \pm\ $0.06 at the $^{12}$CO($J$$=$ 1–0) peak position of the GMC-B. Under the Large Velocity Gradient approximation, we determined a gas density of 2.8 $\times$ 10$^{3}\ $cm$^{-3}$ and a kinetic temperature of 33$^{+9}_{-5}\ $K at the $^{12}$CO($J$$=$ 1–0) peak position of the GMC-B. Moreover, we determined 2.5 $\times$ 10$^{3}\ $cm$^{-3}$ and 25$\ \pm\ $2 K as the averaged values within the whole GMC-B. We concluded that dense molecular gas is formed everywhere in the GMC-B because the derived gas density not only at the peak position of the GMC, but also averaged over the whole GMC, exceeds 10$^{3}\ $cm$^{-3}$. On the other hand, the kinetic temperature averaged over the whole GMC-B, 25 K, is significantly lower than that at the peak position, 33 K. This is because the H II regions are lopsided to the northern part of the GMC-B; thus, OB stars can heat only the northern part, including the $^{12}$CO($J$$=$ 1–0) peak position, of this GMC.
X-Ray Groups of Galaxies at 0.5 1 in zCOSMOS: Increased AGN Activities in High Redshift Groups
Authors: Tanaka Masayuki , Finoguenov Alexis , Lilly Simon J. , Bolzonella Micol , Carollo C. Marcella , Contini Thierry , Iovino Angela , Kneib Jean-Paul , Lamareille Fabrice , Le Fevre Olivier , Mainieri Vincenzo , Presotto Valentina , Renzini Alvio , Scodeggio Marco , Silverman John D. , Zamorani Gianni , Bardelli Sandro , Bongiorno Angela , Caputi Karina , Cucciati Olga , De La Torre Sylvain , De Ravel Loic , Franzetti Paolo , Garilli Bianca , Kampczyk Pawel , Knobel Christian , Kovac Katarina , Le Borgne Jean-Francois , Le Brun Vincent , LÓPez-Sanjuan Carlos , Maier Christian , Mignoli Marco , Pello Roser , Peng Yingjie , Perez-Montero Enrique , Tasca Lidia , Tresse Laurence , Vergani Daniela , Zucca Elena , Barnes Luke , Bordoloi Rongmon , Cappi Alberto , Cimatti Andrea , Coppa Graziano , Koekemoer Anton M. , Mccracken Henry J. , Moresco Michele , Nair Preethi , Oesch Pascal , Pozzetti Lucia , Welikala Niraj 
Published: March 2014

Abstract
We present a photometric and spectroscopic study of galaxies at 0.5 $\lt$${z}$$\lt$ 1 as a function of the environment based on data from the zCOSMOS survey. There is a fair amount of evidence that galaxy properties depend on the mass of groups and clusters, in the sense that quiescent galaxies prefer more massive systems. We base our analysis on a mass-selected environment using X-ray groups of galaxies, and define the group membership using a large number of spectroscopic redshifts from zCOSMOS. We show that the fraction of red galaxies is higher in groups than in the field at all redshifts probed in our study. Interestingly, the fraction of [O II] emitters on the red sequence increases at higher redshifts in groups, while the fraction does not strongly evolve in the field. This is due to increased dusty star-formation activities and/or increased activities of active galactic nuclei (AGNs) in high-redshift groups. We investigate these possibilities using the 30-band photometry and X-ray data. We find that the stellar population of the red [O II] emitters in groups is old, and there is no clear hint of dusty star-formation activities in those galaxies. The observed increase of red [O II] emitters in groups is likely due to increased AGN activities. However, since our overall statistics are poor, any firm conclusions need to be drawn from a larger statistical sample of ${z}$$\sim$ 1 groups.
Processing of Polycyclic Aromatic Hydrocarbons in Molecular-Loop Regions near the Galactic Center Revealed by AKARI
Authors: Kaneda Hidehiro , Ishihara Daisuke , Mouri Akio , Oyabu Shinki , Yamagishi Mitsuyoshi , Kondo Toru , Onaka Takashi , Fukui Yasuo , Kawamura Akiko , Torii Kazufumi 
Published: March 2014

Abstract
We present an AKARI mid-infrared diffuse map of an area of about 4$^{\circ}$$\times$ 3$^{\circ}$ near the Galactic center in the 9 $\mu$m band. The band intensity is mostly attributed to aromatic hydrocarbon infrared emissions of carbonaceous grains at wavelengths of 6.2, 7,7, 8.6, and 11.3 $\mu$m. We detected 9 $\mu$m emission structures extending from the Galactic plane up to a latitude of $\sim$ 2$^\circ\!\!\!.$5, which have spatial correspondence to molecular loops revealed by NANTEN $^{12}$CO ($J$$=$ 1–0) observations. We have found that the surface brightness at 9 $\mu$m is suppressed near the foot points of the CO loops. The ratios of the 9 $\mu$m to the IRAS 100 $\mu$m brightness show significant depression near such bright regions in CO emission. With AKARI near-infrared 2.5–5 $\mu$m spectroscopy, we find that the 3.3 $\mu$m aromatic hydrocarbon emission is absent in the region associated with the loop, suggesting the processing and destruction of carbonaceous grains in the CO molecular loops.
Combined Spectral and Timing Analysis of the Black Hole Candidate MAXI J1659−152, Discovered by MAXI and Swift
Authors: Yamaoka Kazutaka , Allured Ryan , Kaaret Philip , Kennea Jamie A. , Kawaguchi Toshihiro , Gandhi Poshak , Shaposhnikov Nicholai , Ueda Yoshihiro , Nakahira Satoshi , Kotani Taro , Negoro Hitoshi , Takahashi Ichiro , Yoshida Atsumasa , Kawai Nobuyuki , Sugita Satoshi 
Published: March 2014

Abstract
We report on X-ray spectral and timing results of a new black hole candidate (BHC), MAXI J1659$-$152, with an orbital period of 2.41 hr (shortest among BHCs) in a 2010 outburst from 65 Rossi X-ray Timing Explorer (RXTE) observations and 8 simultaneous Swift and RXTE observations. According to the definitions of the spectral states in Remillard and McClintock (2006, ARA&A, 44, 49), most of the observations have been classified into the intermediate state. All of the X-ray broadband spectra can be modeled by a multi-color disk plus a power-law with an exponential cutoff or a multi-color disk plus a Comptonization component. During the initial phase of the outburst, a high-energy cutoff was visible at 30–40 keV. The innermost radius of the disk gradually decreased by a factor of more than 3 from the onset of the outburst, and reached a constant value of 35$\ d_{10}$cos$\ i$$^{-1/2}$ km, where $\ d_{10}$ is the distance in units of 10 kpc and $\ i$ is the inclination. The type-C quasi-periodic oscillation (QPO) frequency varied from 1.6 Hz to 7.3 Hz in association with a change of the innermost radius, while the innermost radius remained constant during the type-B QPO detections at 1.6–4.1 Hz. Hence, we suggest that the origin of the type-B QPOs is different from that of type-C QPOs, the latter of which would originate from the disk truncation radius. Assuming the constant innermost radius in the latter phase of the outburst as the innermost stable circular orbit, the black hole mass in MAXI J1659$-$152 is estimated to be 3.6–8.0$\ M_{\odot}$ for a distance of 5.3–8.6 kpc and an inclination angle of 60$^{\circ}$–75$^{\circ}$.
A Method of Identifying AGNs Based on Emission-Line Excess and the Nature of Low-Luminosity AGNs in the Sloan Digital Sky Survey. II. The Nature of Low-Luminosity AGNs
Authors: Tanaka Masayuki 
Published: March 2014

Abstract
We have developed a new method of identifying active galactic nuclei (AGNs) and studied the nature of low-luminosity AGNs in the Sloan Digital Sky Survey. This is the latter part of a series of papers in which we consider correlations between the AGN activities and the host-galaxy properties. Based on a sample of AGNs identified by a new method developed in the former part (2012, PASJ, 64, 36), we found that AGNs typically show extinction of $\tau_V$$=$ 1.2, and exhibit a wide range of ionization levels. The finding of ionization levels motivated us to use [O II] $+$ [O III] as an indicator of AGN power. We found that AGNs are preferentially located in massive, red, early-type galaxies. Taking into account a selection bias of the Oxygen-excess method, we showed that strong AGNs are located in active star-forming galaxies, and that rapidly growing super-massive black holes are located in rapidly growing galaxies, which clearly shows the coevolution of super-massive black holes and their host galaxies. This is a surprising phenomenon, given that the growths of black holes and host galaxies occur on their respective physical scales which are very different. Interestingly, the AGN power does not strongly correlate with the host-galaxy mass. It seems that the mass works as a ``switch'' for activating AGNs. The absence of AGNs in low-mass galaxies might be due to the absence of super-massive black holes there, but a dedicated observation of the nuclear region of nearby low-mass galaxies would be necessary to obtain a deeper insight into it.
OAO/ISLE Near-IR Spectroscopy of IRAS Galaxies
Authors: Matsuoka Yoshiki , Yuan Fang-Ting , Takeuchi Yoshitaka , Yanagisawa Kenshi 
Published: March 2014

Abstract
We present the results of the near-infrared (IR) spectroscopy of nine IRAS galaxies (NGC 1266, NGC 1320, NGC 2633, NGC 2903, NGC 3034, Mrk 33, NGC 7331, NGC 7625, NGC 7714) with the ISLE imager and spectrograph mounted on the Okayama Astrophysical Observatory 1.88-m telescope. [Fe II] 1.257$\ \mu$m and Pa$\beta$ emission lines were observed for the whole sample, while H$_2$ 2.121$\ \mu$m and Br$\gamma$ lines were additionally obtained for two sources, whose flux ratios were used as a diagnostic tool of dominant energy sources of the galaxies. We found that the nucleus of NGC 1266 is most likely a low-ionization nuclear emission-line region (LINER), while NGC 2633 and NGC 2903 possibly harbor active galactic nuclei (AGNs). No AGN or LINER signal is found for other objects. In addition, we found the spectral features, which are indicative of some unusual phenomena occurring in the galaxies, such as the large [Fe II] line widths compared to the local escape velocity in NGC 1266. The present work shows the potential ability of ISLE to shed new light on the nature of infrared galaxies, either through a statistical survey of galaxies or an exploration of spectral features found in individual objects.
Data-Oriented Diagnostics of Pileup Effects on the Suzaku XIS
Authors: Yamada Shin’ya , Uchiyama Hideki , Dotani Tadayasu , Tsujimoto Masahiro , Katsuda Satoru , Makishima Kazuo , Takahashi Hiromitsu , Noda Hirofumi , Torii Shunsuke , Sakurai Soki , Enoto Teruaki , Yuasa Takayuki , Koyama Shu , Bamba Aya 
Published: March 2014

Abstract
We present the results of a systematic study of pileup phenomena seen in the X-ray Imaging Spectrometer, an X-ray CCD instrument, onboard the Suzaku observatory. Using a data set of observed sources in a wide range of brightness and spectral hardness, we characterized the pileup fraction, spectral hardening, and grade migration as a function of the observed count rate in a frame per pixel. Using the pileup fraction as a measure of the degree of pileup, we found that the relative spectral hardening (the hardness ratio normalized to the intrinsic spectral hardness), branching ratio of split events, and that of detached events increase monotonically as the pileup fraction increases, despite the variety of brightness and hardness of the sample sources. We derived the pileup fraction as a function of radius used for event extraction. Upon practical considerations, we found that events outside of the radius with a pileup fraction of 1% or 3% are useful for spectral analysis. We present relevant figures, tables, and software for the convenience of users who wish to apply our method for their data reduction of piled-up sources.
Star Formation and AGN Activity in Galaxies Classified Using the 1.6 μm Bump and PAH Features at z = 0.4–2
Authors: Hanami Hitoshi , Ishigaki Tsuyoshi , Fujishiro Naofumi , Nakanishi Kouichiro , Miyaji Takamitsu , Krumpe Mirko , Umetsu Keiichi , Ohyama Youichi , Shim Hyunjin , Im Myungshin , Lee Hyoung Mok , Lee Myung Gyoon , Serjeant Stephen , White Glenn J. , Willmer Christopher N. , Goto Tomotsugu , Oyabu Shinki , Takagi Toshinobu , Wada Takehiko , Matsuhara Hideo 
Published: March 2014

Abstract
We studied the star-formation and AGN activity of massive galaxies in the redshift range $ z$ $ =$ 0.4–2, which were detected in a deep survey field using the AKARI InfraRed (IR) astronomical satellite and Subaru telescope toward the North Ecliptic Pole (NEP). The AKARI/IRC Mid-InfraRed (MIR) multiband photometry was used to trace the star-forming activities with Polycyclic Aromatic Hydrocarbon (PAH) emission, which is effective not only to distinguish between star-forming and AGN galaxies, but also to estimate the Star Formation Rate (SFR) with converting its flux to the total emitting IR (TIR) luminosity. In combination with the analyses of the stellar components, we studied the MIR SED features of star-forming and AGN-harboring galaxies, which we summarize below: (1) The rest-frame 7.7-$ \mu $ m and 5-$ \mu $ m luminosities are good tracers of star-forming and AGN activities from their PAH and dusty tori emissions, respectively. (2) For dusty star-forming galaxies without AGN, their SFR shows a correlation that is nearly proportional to their stellar mass, and their specific SFR (sSFR) per unit stellar mass increases with redshift. Extinctions estimated from their TIR luminosities are larger than those from their optical SED fittings, which may be caused by geometric variations of dust in them. (3) Even for dusty star-forming galaxies with AGN, SFRs can be derived from their TIR luminosities with subtraction of the obscured AGN contribution, which indicates that their SFRs were possibly quenched around $ z$ $ \simeq$ 0.8 compared with those without AGN. (4) The AGN activity from their rest-frame 5-$ \mu $ m luminosity suggests that their Super Massive Black Holes (SMBHs) could already have grown to $ \simeq$ 3 $ \times$ 10$ ^{8}$ $ M_{\odot}$ in most massive galaxies with 10$ ^{11}$ $ M_{\odot}$ at $ z$ $ \lt$ 1.2, and the mass relation between SMBHs and their host galaxies has already become established by $ z$ $ \simeq$ 1–2.
Early Evolution of Spherical Ejecta Expanding into the Circumstellar Matter at Ultra-Relativistic Speeds
Authors: Shigeyama Toshikazu , Suzuki Akihiro , Nakamura Ko 
Published: March 2014

Abstract
We present a new self-similar solution describing the early evolution of an ultra-relativistic flow resulting from a collision of homologously expanding spherical ejecta with the circumstellar matter, in which a shock wave propagates in the circumstellar matter, while a weak discontinuity propagates in the ejecta at the sound speed.
Suzaku X-Ray Observation of the Dwarf Nova Z Camelopardalis at the Onset of an Optical Outburst
Authors: Saitou Kei , Tsujimoto Masahiro , Ebisawa Ken , Ishida Manabu 
Published: March 2014

Abstract
We present the result of a Suzaku X-ray spectroscopic observation of the dwarf nova Z Cam, which was conducted by chance at the onset of an optical outburst. We used the X-ray Imaging Spectrometer (a 38 ks exposure) and the Hard X-ray Detector (34 ks) to obtain a 0.35–40 keV spectrum simultaneously. Spectral characteristics suggest that the source was in the X-ray quiescent state, despite being in the rising phase of an outburst in the optical band. The spectrum shows a clear signature of circumstellar absorption in excess of interstellar absorption and the reprocessed-emission features of Fe fluorescence and Compton scattering. The extra absorption is explained as being due to partial covering by either neutral or ionized matter. We found a spectral change during the observation, which is attributable only to a change in the circumstellar absorption. Such an X-ray spectral variation was reported for the first time in the case of dwarf novae. We speculate that the variation in the circumstellar absorption is interpreted as a time-varying disk wind, or geometrically flaring disk around the white dwarf during the propagation of a heat wave along inward the accretion disk at the beginning of the outburst, in which optical outburst and X-ray quiescent states co-exist.
Near-Infrared Imaging Polarization Study of M 17
Authors: Chen Zhiwei , Jiang Zhibo , Wang Yuan , Chini Rolf , Tamura Motohide , Nagayama Takahiro , Nagata Tetsuya , Nakajima Yasushi 
Published: March 2014

Abstract
We conducted wide-field ($ \sim$ 8$ '$$ \times$ 8$ '$ ) $ \textit{JHK}_{\rm s}$ imaging polarimetric observations toward the massive star-formation region M 17. The southern H II bar is identified as large-scale infrared reflection nebula (IRN) illuminated by OB stars in the cluster center, while the northern bar shows polarization originating from dichroic extinction. Three small-scale bipolar IRN with centro-symmetric polarization patterns were identified, and their illuminating sources, embedded young stellar objects (YSOs), are most likely the driving sources of bipolar outflows. $ \textit{JHK}_{\rm s}$ polarizations of point sources in M 17 show a wavelength dependence of the polarization of dichroic extinction in the general interstellar medium, indicating $ \alpha$$ \sim$ 1.8 for the empirical relation $ P$$ \propto$$ \lambda^{-\alpha}$ of interstellar polarization. The distribution of the polarization angle shows two peaks at 170$ ^{\circ}$ and 110$ ^{\circ}$ , indicating a non-uniform magnetic field structure in M 17. The direction of the magnetic field in the cluster region is south-north. However, the magnetic field in the H II region is roughly between 100$ ^{\circ}$ –140$ ^{\circ}$ , roughly perpendicular to the Galactic disk. Such a configuration indicates that the magnetic field in the cluster region is twisted from the primordial orientation in the cluster formation. The magnetic field in the southern bar has a total strength of $ \sim$ 230$ \ \mu$ G, and is 40$ ^{\circ}$ inclined to the plane of the sky. The outflows driven by YSOs in M 17 show a poor relation with the surrounding magnetic fields. This fact implies that the magnetic field in M 17 does not dominate the orientations of protostars formed inside.