南極からの[N II] 1.46 THz 輝線による
銀河面サーベイ梅本智文 (国立天文台)

南極からの遠赤外線·テラヘルツ波で探る宇宙
2022年3月14日

l=198l=236

FUGIN Project(Umemoto et al. 2017 PASJ, 69,78)• Using mul -beam receiver FOREST,OTF mapping of the Galac c planein 12CO, 13CO, C18O(J=1-0),
simultaneously

Mapping area:
inner disk: l = 10°〜50° |b|≦1°

l=50

Spiral arms, interarm, bar/barend,outer disk: l = 198°〜236° |b|≦1°Comparison with inner disk

l=10

ti

ti

NASA/R. Hurt

3 color l-v diagram
Aql spur

Norma

Scutum

Sagi arius

tt

red：12CO
green：13CO
blue：C18O

銀河面における高密度ガスの割合•

K.Torii et al. 2019, PASJ, 71,

5kpcにわたる領域での高密度ガスの割合 ~ 3%•渦状腕では ~ 5%に対しbar 領域や渦状腕の間では ~ 0.1-0.4%– これらの領域での星形成率の違いか?

•距離 ~ 5.5–8kpc⇄~1pcの分解能•

FUGIN データは分子雲の総質量を求め高密度ガスが集中する星形成領域を検出できる

4

RIWHQREVHUYHGWKURXJKWKHFROOLVLRQDOO\H[FLWHGK\SHU¿QHVSLQÀLSWUDQVLWLRQRIK\GURJHQ
DW 0+] λaFP  7KH FORXGV DOVR UDGLDWH DZD\ HQHUJ\ E\ HPLVVLRQ LQ WKH LRQL]HGFDUERQ ¿QH VWUXFWXUH OLQH >&,,@  $W GHQVLWLHV >10 cm−, gas thermal energy can also be

星間物質のガスの循環(N II)(C II)

Warm neutral
and ionized gas

Formation ofcold HI clouds

Disruption ofmolecular clouds(C II)(C II)

(C I)

(C I)

CO

CO

Formation ofmolecular clouds

Stellarevolution
Star formation

HD
CO

FIGURE 1.7(C II)(C II)O

Walker (2016)/LIHF\FOHRIWKH,606WDUWLQJDWWKHWRSRYHUODSSLQJVXSHUQRYDHVKRFNZDYHVVZHHSXSTHzにおける原子・分子輝線(1.46THz, 205µm)

Mauna Kea 1.5mm
Chanantor 0.60mm
Dome Fuji 0.14mm
Dome Fuji 0.10mm

Kuno 資料より

PLWWLQJFORXGVLQYHORFLW\VSDFH$VDPSOH>&,,@VSHFWUXPWDNHQDORQJRQHOLQHRIJKWKH0LON\:D\ZLWKWKHKHWHURG\QHLQVWUXPHQWIRUWKHIDULQIUDUHG +,),  VHHDERDUGWKHPHerschel space observatoryLVVKRZQLQ)LJXUH$VSDUWRIWKH

COBE/FIRASによる[C II] & [N II]
158µm (CII) emission• 角度分解能7 、速度分解能
1000km/sで [C II],[N II] 全天
マップ
3 25 70–1120• [C II] 輝線は赤外線連続波の~0.3% と星間物質の冷却で最も支配的な輝線205µm (NII) emission• [N II]輝線 の強度は [C II]輝線の10分の１程度–0.2

0.3 2.5 7

12• [N II] 輝線は強く電離した領域--> [C II] と[N II]と比較すれば[C II] が電離ガスまたは中性ガ
Fixsen, Bennett, & Mather (1999)
ス起源なのか決められる&2%(),5$6LPDJHVRI0LON\:D\>&,,@μPHPLVVLRQWRS DQG>1,,@μm emis-

P ,PDJHVZHUHPDGHDW° angular and ~1000 km/s velocity resolution. Black swaths

[C II] Galactic Plane Survey by BICE

• Balloon-borne Infrared Carbon Explorer
PLATE 32

• 15ʼ angular resolution & 175 km/s velocity resolution

PLATE 33

Nakagawa et al. (1998)
FIG. 8.ÈFar-infrared [C II] line intensity contour map obtained by BICE with a spatial resolution of 15@. Contour levels are 0.3, 0.6, 1, 1.5, 2, 3, 4, 6, and 9 ] 10~4 ergs s~1 cm~2 sr~1. The
shading shows the observed area. Representative bright sources are labeled.
NAKAGAWA ET AL. (see 115, 264)

Herschel [C II] 銀河面サーベイ• Galactic Observations of Terahertz C+

and N+ (right) line intensities. The low velocity resolutionsr(GOT C+)

h
t
!
m
y
s
n
e
+
s
r
e
r
d Figure 2:GOTC+ observations along line of sights• Herschel(3.5m)/HIFIによる[C II]
銀河面サーベイ、12” の空間分解能、0.1 km/s速度分解能• 銀河面の452視線方向を観測• Every 0.87 (|l|<60 ), 1.3 (30 <|l| <60 ), 4.5 (60 < |l| <90 ), and
4.5 to 13.5 (|l| >90 )• b=0 , 0.5 , and 1.0 , 2.0 (|l|>90 )resulted in an under-sampled survey (from Pineda etal 2010)Langer et al. (2010), Pineda et al. (2013), Langer et al. (2014)

2

The Astrophysical Journal, 814:133 (21pp), 2015 December 1

Goldsmith et al.
Table 3
(Continued)

Herschel [N II] Galactic plane survey
LOS LabelLongitudeOBSID[N II] 122 μm(a )Intensity±(Err)The Astrophysical Journal, 814:133 (21pp), 2015RDecember
1[×10−8](W m−2 sr−1)[N II] 205 μm

σ[×10−8]R (a )

Intensity±(Err)[×10−8](W m−2 sr−1)n(e)±(Err)

N(N+)±(Err)(cm−3)[×1016] et al.
Goldsmith(cm−2)• [N II] at 122 & 205 µm with PACS(5x5)G344.8+0.0
344.7830
1342267185(2)
1.37±0.020
0.42(3)0.80±0.056
36.4±4.3
1.3±0.02
G345.7+0.0
345.6520
1342267869(2)
12.60±0.044
7.55(2)
5.44±0.081
59.6±1.57.7±0.03
G346.5+0.0
346.5220
1342267178(2)2.90±0.020
0.77(2)
1.71±0.059
36.0±2.1
2.8±0.02
G347.4+0.0
347.3910
1342264238(2)
1.92±0.013
0.54(3)
1.32±0.049
27.5±1.8
2.4±0.02
G348.3+0.0
348.2610
1342264237(2)
3.02±0.020
0.90(2)2.07±0.064
27.7±1.5
3.7±0.02
G349.1+0.0
349.1300
1342267870(2)
21.31±0.096
4.41(2)
8.67±0.057
65.7±0.812.1±0.05
G350.0+0.0
350.0000
1342265935(3)
0.36±0.008
0.23(1)<0.22±...
...±...
...±...
G350.9+0.0
350.8700
1342265684(2)
1.42±0.013
0.41(2)
1.22±0.069
18.1±2.1
2.8±0.03
G351.7+0.0
351.7390
1342265683(2)
1.61±0.025
0.48(3)
1.68±0.055
12.1±1.0
4.9±0.07
G352.6+0.0
352.6090
1342265682(2)
1.47±0.021
0.36(3)
1.22±0.055
19.6±1.8
2.6±0.04
G353.5+0.0
353.4780
1342265681(2)
3.68±0.027
0.62(2)
2.95±0.066
20.9±0.9
6.1±0.04
G354.3+0.0
354.3480
1342265680(2)2.33±0.020
0.65(2)
1.53±0.048
29.9±1.7
2.7±0.02
G355.2+0.0
355.2170
1342267874(2)
5.22±0.017
1.34(2)
1.87±0.060
80.5±4.2
2.6±0.01
G356.1+0.0
356.0870
1342265934(2)
2.59±0.020
0.31(3)
1.63±0.038
32.3±1.4
2.8±0.02
G357.0+0.0
356.9570
1342265933(3)
0.35±0.010
0.21(1)<0.18±...
...±...
...±...
-3
G357.8+0.0
357.8260
1342265932(2)
0.82±0.020
0.31(1)<0.19±...
...±...
...±...
G358.7+0.0
358.6960
1342267875(0)...±...
...
(0)...±...
...±...
...±...
Figure 19. Observed
intensity1342265931
ratio of the two (2)[N II] ﬁne 17.30±0.102
structure lines and derived
are plotted as a functionof Galactic longitude.
G359.5+0.0
359.5000
1.69 electron(2)densities 9.16±0.095
42.9±0.814.1±0.08• 149 LOSs selected from GOT C+, 10”(122um),15”(205µm)• Bothe lines are detected in the range -60 ≤ l ≤60• [N II] emission highly correlated with that of [C II]• High electron density(10-30cm )̶> [N II] emission is not from
WIM but from dense WIM associated with SFRs, H II regions

Figure 5. HIFI [N II] spectrum before baseline removal (with positive
continuum offset; shown in red), with continuum offset removed (lower
spectrum; shown in blue), and with third order baseline removed (lower
spectrum; shown in green). There is only a minimal difference between the
spectra with zeroth and third order baselines removed in this case.
Figure 4. Illustration of effect of polynomial baseline removal from PACS
spectra toward G024.3+0.0. A DC offset had previously been removed to yield
FigureComparisonof theasintensitiesof thein[Nthis
II] of205 μm lines.
the 20.
25 spectra
displayed
the red lines
122122
μmand
observation.
The
Thehigher-order
blue squarespolynomial
are the LOS
in the shown
range −30°<l< 30°,and theﬁtting
triangles(spectrain black after
baselineandare removal)
the LOS modestly
positions reducesin the region–60°<l< in−30°
and 30°<l60°.
any residual
offsetthe vicinityof the<lineas The
well
black
equal
intensities(1:1 ofratio),
andII]theblue line
emission.
as dashed
reducingline
thecorresponds
amplitude oftothe
featureto the rightthe [Nspaxels. It is thus reasonable to consider the [N II] emission to

Figure21. Intensities
of [N IIand] 122 and205 uniform
μm transitions
with thosebe spatiallyextendedfairlyin comparedeach pointing
II] 158 μm. The red and blue solid lines are power law ﬁts of theof[C
direction (;1 arcmin in size). Given that the PACS footprint
corresponding [N II] lines vs. [C II]. The black dashed line is a slope of unity,
size is 47″
corresponds
pc at a distance oftransitions
and alsoto[N1.5
II] measured with HIFI as wellindicating
thatandboth that[N II]1′

Goldsmith et al. (2015)8

2.0!"#$%"&'("

G013.90+0.0

G000.0 +0.0

7

Herschel/HIFIによる[C II] [N II] 観測
1.5

6

5

)*%&)"&'("

3

1.0• GOT C+方向の[N II] 輝線観測
T(K)

T(K)

4

0.5

W. D. Langer et al.: [C ii] and [N ii] from d• [C II] 輝線を、強く電離したガスと弱く電離したガスからの寄与を分2Table 2. [C ii] emission and absorption components.

1

離することが可能

0

0.0

•

[C ii] sourcecomponent
Itot (⌧)(K km s 1 )
103.5
33.6
88.5
42.3

LOS
# T
I /I
I /I
T
V
[N II]輝線が強いところでは[C II] しばしば前景のガスによる吸収がみ
label
(K)
observed corrected (K) (kmG031.3 3 6.3
0.93
0.56
2.9
1
G049.1
2
3.7
0.55
0.34
1.5
V (km/s)
V (km/s)られる--> [C II] 輝線の観測だけでは高度に電離したガスの量を過小G316.6 1 5.1
0.94
0.58
1.4
–
G337.0 1 4.3
2.37
1.37
1.0
–
Langer et al.: [C ii] and [N ii] from dense評価
ionized regions
-1
-200

-150

s

-100

-50

0

50

100

150

-0.5
-40 -30 -20 -10 0

200

10 20 30 40 50 60 70 80 90 100
lsr

lsr

1.5

6 2.0

5
1.5

[C II]

5

1.0

4

1.0

T(K)

T(K)

3

T(K)
T(K)

3

0.5

2

2
0.5

3.1.3. F[N II]

1

1

0.0
0.0

0

50

100

150

200

0

-1-0.5
0 -40 -30
20 -20 -10
40 0

-0.5
60 20 30
80 40 50
100 60 70
120 80 90
14010010

V V(km/s)(km/s)

m/s)

lsr lsr

0

10

20

30

40

50

60

70

80

90

100

-1
-100

-75

V (km/s)lsr

Langer, Goldsmith & Pineda (2016)

-50

-25

0

25

V (km/s)lsr

Fig. 1. Main beam temperature versus velocity for [C ii] (blue solid spectra) and [N ii] (red solid spectra) taken with HIFI – see Table Fig.
1 for6.some
A Gaussian fit (black dash) to the line wings of the Vlsr ⇠of the line parameters, and 13 CO(1 0) (black dashed line) from Pineda et al. (2013). Each LOS is labeled with the GOT C+ LOS label.
Some
47 km
s 1 [C ii] component (blue) in G316.6+0.0 using the Vlsr andfeatures that are indicative of [C ii] absorption are highlighted with arrows.
line width of the Gaussian fit (not shown) to the [N ii] emission (red).
1.5
fi

o

G316.6+0.0

4)"&'("

ion tot[C ii] em[N ii] em
region b
Gaussian t of [CtheII]fract
four soufrom [N II] emissioncles, anabsorpti
have thereducedhas a fra
nations,[C ii] lin

6
G049.10+0.0

G031.3+0.0
G013.90+0.0

G000.0 +0.0

ion obs

Assumin[C ii] ingroundItot ([C iifunctionof the reT s is theand T o iglect [Cis likely
re-emissT s and T
the abso
The colu

[N II] 1.46 THz 銀河面サーベイ• [N II] 輝線の特徴• [C II] 輝線の電離ポテンシャルは11.3eVと水素の電離ポテンシャル
13.6eVよりも低いため、[C II]輝線は電離ガス領域と中性ガス領域のどちらからでも生じる。いっぽう、[N II]輝線は電離ポテンシャル
が14.5eVと高い。

• このため[N II]輝線は強く電離した領域で生じる--> [C II]輝線と[N II]
輝線のマップを比較すれば、[C II]輝線が電離した領域からなのか中性ガス領域から来ているのを決定できる• [C II]輝線はしばしば吸収線がみられ、[C II]輝線の観測からだけでは非常に電離したガスを過小評価することになる• 南極からの[N II]1.46 THz輝線銀河面サーベイ• 天の川銀河の広い領域をマッピング観測することで、中性ガスだけ

でなく電離ガスも含めた星間物質の進化の過程を明らかにするのが目的

Detection of 205µm [N II] from Ground• AST/RO at South Pole (1.7m)• The rst detection of 205µm [N II] line from ground-base• [N II] emission reveals the fraction of [C II] emission arises
from the ionized gas and the neutral ISM
L128

OBERST ET AL.

• 27% of [C II] arises from the low-density ionized gas but[N ii] IN CARINANEBULA
73% from the neutral
ISM!

No. 2, 2006

L127
4.1. The [N ii] Line Ratio[N II] emission from Carina nebularfiFig. 1.—[N ii] 205 mm spectrum obtained using SPIFI on AST/RO. These
data were obtained at the peak of the radio continuum contours of the Carina IIwith velocity resolution of 60 km/s
H ii region (Retallack 1983). Velocity resolution is 60 km s!1. The dashed line
shows the intrinsic instrumental profile. The data were smoothed with a Hann

The [N ii] lines provide a distinct probe of the ionization
structure and gas density in H ii regions. Formation of O""
requires energetic 35.1 eV photons, so that the [O iii] lines trace
H ii regions formed by very early-type (O7) stars. Lower energy
photons (14.53 eV) can form N" so that these lines arise from
H ii regions formed by the softer UV radiation of late O-type
or early B-type stars, or from the lower ionization “outskirts” of
H ii regions formed by earlier type stars. Since O"" and N""
have similar ionization potentials (35.1 and 29.6 eV, respectively), an O"" zone contains mainly N"" rather than N". The
twin [N ii] lines have significantly lower critical densities(ncrit ∼ 44 and 293 cm!3 (8000 K) for the 205 and 122 mm lines,
respectively) for thermalization than the [O iii] lines (ncrit ∼510 and 3600 cm!3 (8000 K) for the 88 and 52 mm lines, respectively), so that they make better probes of lower density gas.
Unfortunately, the undersampled ISO LWS mapping of Mizutani et al. (2002) does not directly sample the position where
we obtained our spectrum displayed in Figure 1. The nearest pos
sition is at l p 287!. 550, b p !0!. 583 [R.A. p 10 h 44 m 54.1,"""
decl. p !59!37 17 (J2000.0)], or about 1".27 (more than a fullbeam) offset from our peak line flux position. However, this position is covered by other pixels in the array, for which we obtainan integrated line flux of 21.4 K km s!1, or (3.6 " 0.7) #10!15 W m!2 in our 54! beam. Using the ISO data archive, we
obtain a 122 mm [N ii] line flux of 1.66 # 10!14 W m!2, or making
the extended source correction, a flux of 1.12 # 10!14 W m!2 in
Fig. detector
2.—[N ii]
122(Gry
mm–to–205mm lineintensity ratio as a function of ionized
the 78!.2 LW2 ISO LWS
beam
et al. 2003).
Assuming
gasdensity,n(solidline).
The
open
circleour observed line ratio ofa uniform intensity source, ande correcting for the differencemarks
in
1.5
!
0.64
.
The
ratio
of
the
[C
!15
!2ii] 158 mm to [N ii] 205 mm lines as a function
beam size, the ISO flux is 5.33 # 10 W m referred to ourof ne (dashed line). The filled circle marks the observed line ratio of 9.2 ! 3.9.

Oberst et al. (2006)

and dips to be
the upper J p
ulated at dens
From the I
10!13 W m!2.
responds to 5.
LW4 beam. A
our 54! beam
30% calibrati
205 mm line r
gas density of
we would exp
an upper bou
observed [C iremaining 73%
results supporof the observe
regions, the G
in warm densThis work
OPP-0338149
NNG05GK70
P. A. R. Ade(C. A. Allen,
for their exce
local oscillato
grateful to K.
the TREND ll=221l=236

㸦ὀ 2: Confusion limit ࡣ Bla

l=198

㸦ὀ 3: ࣮࣍ࣥࢆ౑⏝ணᐃ㸧

観測可能領域(2) ࢫ࣌ࢡࢺࣝ⥺ほ㸦෤Ꮨ 50%ࣞ࣋ࣝ㸾᪂ࢻ࣮࣒ࡩࡌ㸧࿘Ἴᩘᖏ

マッピング領域:

࿘Ἴᩘ⠊ᅖ

ឤᗘ(5Ȫ

ȫ=60se(220 GHz)

210-275

0.096 K

Inner disk: l = 221°〜25°|b|≦1° 0.15450385-500350

275-373

0.081

650

600-710

0.21

1000

1010-1060

0.86

1500

1440-1540

1.05

Spiral arms, interarm,bar,
850
787-950G.C.0.34
FUGIN 領域と一部オーバーラップ
1300
1260-1380
0.92
232 < l < 14 (EL >30 ), 221 < l < 25 (EL>20 )㸨ON Ⅼ㸦ὀ 1: ឤᗘࡣ 1 W 'V ࡟ẚ౛㸦ὀ 2: ከ⣲Ꮚཷಙᶵࢆᦚ㍕㸧

l=50

㸦ὀ 3: ศග㟁Ἴ࣓࢝ࣛ[R~10ࠐほ ྍ⬟ኳᇦ㸦㸾᪂ࢻ࣮࣒ࡩࡌ㸧

l=25

南極
l=10
FUGIN

௮ゅ(EL)㉥⦋(Decl.)

> 5°

<㸩8°

>10°

<㸩3°

>20°

<㸫7°

NASA/R. Hurt

南極テラヘルツ10m鏡によるサーベイ• [N II] 1.46THz 銀河面サーベイ• サーベイ領域 l = 221 - 25 (EL>20 ), |b| ≤1 (|b| ≤2 )• 20” grid, ΔT(5σ)=0.75K, 10x10 beams ̶> 75,000h (OTF)x• 銀経にそってOTFによるストリップスキャン ̶> 1度角ストリップ
当たり1.2時間 (OTF)̶> ~200時間 >> いくつかの銀緯ででスト
リップスキャン、又は特定領域のマッピングを実施

Freq. band
(GHz)

Freq. range
(GHz)

Lines

Beam

460

385-540

CO (J=4-3), [C I] 3P1-3P0

250

0.054 K17”

650

575-735

HCl, D2H+

250

0.092 K

11.4”

850

775-965

CO (J=7-6), [C I] 3P2-3P1

250

0.14 K

8.7”

1000

1000-1060

CO (J=8-7), NH+

100

0.35 K

7.4”

1300

1250-1380

CO (J=11-10), H2D+

100

0.47 K

5.7”

1500

1450-1550[N II]

100

0.75 K*

5.0”

Sensi vity (5σ)
Angular Resolu on(τ=10min, Δv=1km/s)(D=10m)titi(*:Tsys=6000K) From Kunoʼs document

The hotter a star burns, thebeburns,
its lifetimeon thewill
main
sequence,
Theshorter
hotter willa starthe shorter
be itslifetime τon
MS ,the main sequence, τMS ,SFRとLIRのプローブとしての[N II]
 M τ MS ≈ 1010 
 M ! 

−2.5

 M 
τ MS ≈ 1010 
 M ! 

−2.5





• [N II] 輝線観測の意義

where
ere
τMS VWHOODUOLIHWLPHRQWKHPDLQVHTXHQFH
\HDUV τMS VWHOODUOLIHWLPHRQWKHPDLQVHTXHQFH
\HDUV galaxies のHerschelの [N II] 観測から、星形成• LIRGsとstar‒forming
0DVVLYHVWDUVKDYHWKHJUHDWHVWOXPLQRVLWLHVDUHWKHODUJHVWFRQWULEXWRUVWRWKHJDODFWLF

0DVVLYHVWDUVKDYHWKHJUHDWHVWOXPLQRVLWLHVDUHWKHODUJHVWFRQWULEXWRUVWRWKHJDODFWLF
率 (SFR) と赤外光度 (LIR)の素晴らしいプローブ (Zhao et al. 2013).
89ÀX[DQGKDYHWKHVKRUWHVWOLIHWLPHV7KHLUSUHVHQFHLVLQGLFDWLYHRIUHFHQWVWDUIRUPLQJ
9ÀX[DQGKDYHWKHVKRUWHVWOLIHWLPHV7KHLUSUHVHQFHLVLQGLFDWLYHRIUHFHQWVWDUIRUPLQJDFWLYLW\DQGFDQEHWUDFHGE\WKH3'5VDQGDWRPLF¿QHVWUXFWXUHOLQHHPLVVLRQWKH\JHQLYLW\DQGFDQEHWUDFHGE\WKH3'5VDQGDWRPLF¿QHVWUXFWXUHOLQHHPLVVLRQWKH\JHQしたがって[N II]輝線光度 L[N II] は、従来の LIR から求めた推定よりも、
HUDWH,QSDUWLFXODUWKH>1,,@μPOLQHZLWKDQLRQL]DWLRQSRWHQWLDOMXVWKLJKHUWKDQWH,QSDUWLFXODUWKH>1,,@μPOLQHZLWKDQLRQL]DWLRQSRWHQWLDOMXVWKLJKHUWKDQK\GURJHQKDVEHHQGHPRQVWUDWHGWREHDQH[FHOOHQWSUREHRIWKHVWDUIRUPDWLRQUDWH 6)5 
より正確なSFRの指標となる
GURJHQKDVEHHQGHPRQVWUDWHGWREHDQH[FHOOHQWSUREHRIWKHVWDUIRUPDWLRQUDWH
6)5 
and infrared dust luminosity(L=KDRHWDO

The Astrophysicald infrared dust luminosity (L,5  =KDRHWDO
 ,5 Journal Letters, 765:L13 (6pp), 2013 March 1•

log SFR = ( −5.31 ± 0.32) + (0.95 ± 0.05) log L[NII]log SFR = ( −5.31 ± 0.32) + (0.95 ± 0.05) log L[NII]




log LIR = (4.51 ± 0.32) + (0.95 ± 0.05) log L[NII]
log LIR = (4.51 ± 0.32) + (0.95 ± 0.05) log L[NII]




where
ere
6)5 VWDUIRUPDWLRQUDWH M⊙ yr −1)−1)6)5 VWDUIRUPDWLRQUDWHL>1,,@M⊙ yrOXPLQRVLW\RI>1,,@OLQH
L⊙)
L>1,,@ OXPLQRVLW\RI>1,,@OLQH
L⊙)
L,5 OXPLQRVLW\RIGXVWLQ,5
L⊙)
L,5 OXPLQRVLW\RIGXVWLQ,5 L⊙)(;$03/(これははたして数百パーセックの(;$03/(

,IWKHLQIUDUHGOXPLQRVLW\L,5, of a dust core is 1000 L ε ZKDWLVWKHH[SHFWHGOXPLQRVLW\スケールでも当てはまるのか?
RIWKH>1,,@OLQH"
WKHLQIUDUHGOXPLQRVLW\L,5 , of a dust core is 1000 L ε ZKDWLVWKHH[SHFWHGOXPLQRVLW\
6WDUWE\VROYLQJ(TXDWLRQIRUL>1,,@, assuming a zero error.
IWKH>1,,@OLQH"
Zhao et al. (2013)
6WDUWE\VROYLQJ(TXDWLRQIRUL, assuming a zero error.

Ronin Wu et al.: Physicalconditions in M83 revealedby the &Herschel
SPIRE
FTS
Relationshipbetween
ΣSFR
[N
II]

where [NII] 205 µm is scaled from the [NII
theoretical emission ratio of 2.6 (see Zhao[NII]輝線の表面輝度と星形成率
moredetails). As to the atomic carbon eof nearby の関係は
galaxies haverevealed
that theZhao et al. (2013)
SFRΣ
Zhao
et
SFR
atomic carbon (traced by [CI] 609 µm) toal.(2013)の結果よりも傾きがなだ
stays comparable with the emission of COa variety of II]輝線の表面輝度はenvironments, and it has been
らかで、[N
the atomic carbon emissions can be a goo-2で一定Σ
10-1 Moyr-1 kpc
SFR >(Gerin
tracer& Phillips
2000;
Israel & Baa
We investigate how the [NII] 205 µm aの値を取るようにみえる
emissions relate to ⌃SFR and how their rel
Kinnicutt et al. (2007)
ところが、[Npare with the II]輝線の表面輝度とexisting one between ⌃SF
J = 1 SFRΣ
0 transition(Kennicutt et al
星形成率
SFR をM83銀河全⌃SFR is calibrated with the H↵ and 2
体に渡って積分すると、Zhaoの関Because [CI] 370 µm is observed at a spat
00⇠
38
while the spatial resolutions of t
係とよく一致する.
and ICO(1 0) maps are comparable (⇠ 1
このことは、[NII]輝線の表面輝度
spectively), we compare
the pixel-by-pixe[NII] 205 µmSFRの比例関係は、銀surface brightness with the ⌃と星形成率
ICO(1 0) with ⌃SFR at a spatial resolution o
河全体のスケールでは当てはまる[CI] 370 µm surface brightness with the ⌃S
resolution ofpc
3800scale.では当てはま. The ⌃SFR is calculated fro
が、~30024 µm photometry maps of M83 following
らないないかもしれないことを示し
given in Hao et al. (2011). Figure 8 shows thlationship exists between the values of [NII]ている
et al.⌃(2018)
Fig. 8: RelationshipsWu
between
SFR and [NII] 205 µm (reddots), between ⌃SFR and [CI] 370 µm (green squares), and ⌃SFR . Compared with the ICO(1 0) , the su

•

•

•

天の川銀河の渦状腕の接線付近方向• 通常は低密度のwarm ionized medium WIMを検出できない。しかし接線付近方向では視線方向のパスが長くなるため、検出できる可能性• 電離ガス、HI中性原子ガス、COによる分子ガスといった異なる層が、
終端 VLSR 速度の関数として輝線プロファイルにあらわれると期待• WIMが渦状腕の重力ポテンシャルに落ち込んで圧縮され、高密度ガス
A&A 607, A59 (2017)にうまく変換されている様子を知ることができるかもSun

tangent spectra
A&A 607, A59 (2017)

towardsun suntowardtangent spectra

VLSR Ë
Ádistance from Galactic center
VLSR Ë
Ádistance from Galactic center

WIM: [C II] & [NII]
Scutum inner edge
WIM: [C II] & [NII]
Scutum inner edge

Molecular gas layer:
12CO, [C II] & [NII]Molecular gas layer:
12CO, [C II] & [NII]+ Galactic center
Fig.+1. Galactic
Schematiccenterviewof the Scutum
tangency showing theLangeretspiralal. arm(2017)

Fig. 2. A 13 CO longitude-velocity plot of the Scutum arm in the regionl ⇠ 29 to 33 at b = 0 , where we mark the inner (black solid line)

Ionized Gas in the Scutum Arm• There is highly ionized gas within the arm with 1-20 times
electron density (0.2 - 0.9 cm-3) of the interarm WIM• [N II] emission arises from shock compression layers of the A&A 607, A59
A&A 607, A59 (2017)
WIM, accelerated by
the gravitational potential of the arm

W. D. Langer et al.: Ionized gas in the Scutum spiral arm

Scutum spiral arm tangency: l = 30.0! to 31.75!

to the molecular spiral arm are also consistent with 13 CO in thetangent spectra(l–VLSR ) map shown in Fig. 2.

In Fig.
4. Discussion
a function o(left panel)
Our SOFIA observations provide a rich data set of velocity resolved [C ii] and [N ii] emissions in the Scutum tangency. Ourbols indica
VLSR Ë
results show widespread clear detections of [C ii] and [N ii]
includes thfrom Galactic center
along all LOSs, especially, at velocities VLSR = 60 to 125Ádistance
km s 1function ofand at |b| < 0 .25. Although weaker at higher latitudes there is
detectable emission at least up to b = 1 .3. The unique combinaGRS datation of [C ii] and [N ii] provides a powerful tool to analyze thenear b = 0 .
ionized gas component in spiral arms and the ability to isolate
strong 13 CO[C ii] emission in the neutral and ionized gases.
itude value
In general the WIM is a highly ionized, low density, n(e) ⇠WIM: [C II] & [NII]
0.02 to 0.1 cm 3 , high temperature, T k = 6000 to 10 000 K Molecular gas layer:
It is nearlyedge the Galactic midplane (cf.
12CO, [C II] & [NII]
gas that fills Scutum
a 2–3 kpcinner
layer aroundscale heighFerrière 2001; Cox 2005; Ha↵ner et al. 2009). It is estimated tovelocity ran
contain about 90% of the ionized gas in the Galaxy and has a filling factor of order 0.2 to 0.4, which may depend on height above
molecular
the plane. At the midplane the filling factor may be as small
consistentas 10%. It has been studied with pulsar dispersion measurescale heighments (Cordes & Lazio 2003), H↵ emission (Ha↵ner et al. 2009,2016), and nitrogen emission lines in the visible (Reynolds et al.
the uncerta2001). More recently the WIM has been detected in absorption
have simila
with [N ii] (Persson et al. 2014). The [C ii] and [N ii] emission
the tangenc
lines can also be used to map the WIM, however, the low densiof the gas dties of the
WIM
make it difficult
to detect their emission throughGalactic
center+out most of the Galaxy. However, the spiral arm tangencies o↵ersion fromtFig
a uniquegeometrythatenablesthedetection
of
the
WIM
in
[N
ii
]
2
Fig.
1. Schematic
viewcrossof theScutumspiraltangency
showingn(e)the , andFig.
schematic
radialview
ofthearmspiralarm perpenet
al.
l ⇠
and
[C9.ii]Abecause
they Langer
correspondto section
regionswitha(2017)very
longstructure
of
the
gas
layers(adapted
from
Fig.
6
in
Velusamyetal.
2015).
dicularto inthea relatively
LOS to Scutum
spiral dispersion.
arm tangency
showing the inner to and [N ii] s
path
lengthnarrow velocity
The WIMThe emission of key gas tracers along the tangency, [C ii], [N ii], and CO andtoward sun

[CII]
[NII]
13CO
HI/50

GaussFit components
In Molecular Gas[CII] & [NII] Residual:
In WIM Gas

[CII]
[NII]
13CO

Spiral Arm Tangency in Southern Sky• Scutum-Centaurus, Carina‒Sagittarius, Norma, and Perseus
spiral arm tangencies in the southern visible sky from S.P.

• WIM traced by [N II] emission arises from shock

?

l
a
s
er

iv
n
U
A&A
578,
A135
(2015)
Velusamy et al.:Spiralarm
structurewith spiral[C ]
compressionT. layers
inducedbytracedthedensity waves?

Velusamy et al. (2015)

Summary• 中性ガスだけでなく電離ガスの星間物質の進化過程を理解するためには、テラヘルツ帯の原子輝線の観測が重要.

• [N II] 輝線の電離ポテンシャル (14.5 eV) は水素より高いため, [C II]輝線と[N II]輝線の比較から、[C II]輝線がどれ位の割合で電離したガスと中性のガスから来ているかわかる.

• そこで、南極からのヘテロダイン受信機カメラで[N II] 1.46
THz 輝線による銀河面サーベイを提案したい.

• [N II] 輝線による星形成領域の観測から, はたして数百パー
セックのスケールでも[N II]輝線光度と星形成率 (SFR) に良い相関があるか、さらに、渦状腕の接線領域での視線速度の違いから、[N II]輝線によってトレースされる低密度のWIMが、渦状腕の密度波によって圧縮され、高密度ガスに変換されている様子を明らかにできるかもしれない.

GBT Di use Ionized Gas Survey• GDIGS in the Galactic plane(Anderson et al. 2021)• 4 - 8 GHz radio recombination line (RRL) emission, Hnα,
Hnβ ,Hnγ RRLs and molecular lines (ex. H2CO, CH3OH)• Survey range: -5 ≤ l ≤ 32.3 , |b| ≤ 0.5
spacial resolution ~ 2.65ʼ (Hnα), dT~ 10mK
• dv=0.5 km/s, A&A
proofs: manuscript no. AA-2020-40223

Fig. 1. The location of the eight lines of sight observed in [N ii], RRL, and [C ii], indicated + signs, superimposed on a moment 0 integrated
intensity map of the Hnα RRL Green Bank Telescope Diffuse Ionized Gas Survey (GDIG; (Anderson et al. 2021)). None of the LOS intersect thelocations of the brightest compact emission, although many intersect with larger ionized zones.
40

4

4

20

5

50

30

G021.7+0.0

Hα RRL (black)[CII] (blue)[NII] (red)

3

ff

30

G024.3 + 0.0
G023.5 + 0.0

Hnα RRL (black)[CII] (blue)[NII] (red)G020.9 + 0.0
15

6

40
3

Hα RRL (black)[NII] (red)[CII] (blue)

425

Hα RRL (black)[CII] (blue)[NII] (red)5[N II], [C II] & RRL from D-WIM
A&A proofs: manuscript no. AA-2020-40223• [N II] at 205 µm toward 8 LOS by SOFIA• T= 3400 -8500 K, high electron density n(e)=10 -35 cm-3

comparing from Herschel PACS 122 µm (Langer et al. 2021)• Dense warm gas is from SFRs associated with molecular gas,
Fig. 1. The location of the eight lines of sight observed in [N ii], RRL, and [C ii], indicated + signs, superimposed on a moment 0 integrated
intensity map of the Hnα RRL Green Bank Telescope Diffuse Ionized Gas Survey (GDIG; (Anderson et al. 2021)). None of the LOS intersect thelocations of the brightest compact emission, although many intersect with larger ionized zones.

contribute > 50% of the observed [C II]

•

40

6

2

25

50

V

mb

-25

0

25

50

V

(km/s)

75

-10

100

0

(km/s)

25

50

1.5

75

V

LSR

LSR

15

10

2

5

1

0

0

A

T (mK)

-1

-5

-1
100

75

3
mb

0

15

T (K)

0

0

-10

4

0

0

0

20

1

10

0

mb

A

20

1

5

1

3

T (K)

mb

10

30

5

2

10

T (K)

T (mK)

2

4

Hα RRL (black)[NII] (red)[CII] (blue)

T (mK)

20

40
3

15

Hα RRL (black)[CII] (blue)[NII] (red)

25

A

3

T (mK)Hα RRL (black)[CII] (blue)[NII] (red)30G024.3 + 0.0
G023.5 + 0.0

Hnα RRL (black)[CII] (blue)[NII] (red)G020.9 + 0.0[C II]
absorption

30

G021.7+0.0

mb

100

125

-1
150

-5
0

25

50

(km/s)

125

150

-1
175

(km/s)

LSR

40

10

100

V

LSR

50

75

4

40

1.00

G025.2 + 0.0

V(km/s)

LSR

100

125

150

-0.5
175

25

5

20

4

15

3

10

2

5

1

0

0

-5
25

50

75

100

V

125

(km/s)

LSR

150

-1
175

20

0.50

20

2

10

0.25

10

1

0

0.00

0

0

-0.25
175

-10

-10
0

25

50

75

100

V

(km/s)

LSR

125

150

A

6

30

T (mK)

30

3

0.75

30

A

A

A

75

7

G028.7 + 0.0
Hα RRL (black)[CII] (blue)[NII] (red)

mb

50

35

G027.0 + 0.0
Hα RRL (black)[CII] (blue)[NII] (red)

T (K)

25

8

mb

0

40

T (K)

-25

9

mb

-5
-50

G026.1 + 0.0
Hα RRL (black)[CII] (blue)[NII] (red)

T (K)

mb

0.0

0

T (K)

0.5

5

T (mK)

1.0

10

45

T (mK)Hα RRL (black)[CII] (blue)[NII] (red)T (mK)

RRL

5

50

4

20

T (K)

[N II][C II]

4

25

50

75

100

V

125

(km/s)

LSR

150

-1
175

Spatially
Resolved[N byII]& [CI]
370µm
Ronin Wu et al.: Physicalconditions in M83 revealed
the Herschel
SPIRE FTS(a)

M83 @4.5Mpc

Wu et al. (2018)(b) most widely detected emission line from the observed region of M83.
The [NII]205μm(a) is the(b)distributionOnof the[NII]the205 µmline. Figure
4a shows ofthethecontinuum-removed
theobserved
contrary,
spatialdistribution[CI] 370 μmcoadded
emission appears more concenwithin a rangeof 1452< ⌫ <distribution
1467 GHz. The ofverticalin each [CI]pixel ranges
between
1:pixelIllustrationof thespatialthe axis
observed
370 µmline. The left panel shows the contin
17 trated
2 around1
1 the nuclear region.
9.3 ⇥ 10W m sr Hz . Figure 4b shows the measured [NII] 205 µm intensity distribution, in

coadded spectrum on every pixel within a range of 801 < ⌫ < 815 GHz.
7 The vertical axis in each pixel r