[CI] を用いた高赤方偏移銀河での分子ガス探査
参考文献
Offner et al. 2014, MNRAS, 440 L81
Alaghband-Zadeh et al. 2013, MNRAS, 435, 1493
Ryu Makiya (IoA, JSPS fellow)
第二回 微細構造輝線研究会

14年12月2日火曜日

Motivation• 宇宙の星形成史が知りたい• そのために cold gas の進化が, 特に H の進化が
2

知りたい

• 疑問
• H を真にトレースする観測量は何か？
• 温度や密度分布は？
• local との違いは？
2

14年12月2日火曜日

Atomic carbon : [CI]• neutral ISM をトレース• 炭素原子の微細構造輝線は P → P と P → P の二種
3

2

3

1

3

1

3

0

類だけなので励起温度や質量などの物理量を決めやすい• local galaxies を観測したところ, [CI] と CO は空間的にとてもよく相関している• [CI] を観測すれば CO の縮退も解ける• [CI] は H のトレーサーとしても使える
2

14年12月2日火曜日

Excitation

AA51CH04-Walter

Species[OI][OIII]

ARI

tronomy- Mitaka
on 11/10/14.
For personaluse only.
rsity of Tokyo- Instituteof Astronomy- Mitaka
on 11/10/14. For personal use only.

Species[O[CI][O
COIII]
[CII]
[NII]
[CI]
CO
HCN

HCN

14年12月2日火曜日

10:18

Transition

potential(K)λ (µm)

ν (GHz)Einstein A (s−1 )ncrit (cm−3 )Fundamental parameters for C and CO

Table[CII] 1[NII]

24 July 2013

3P → 3P
228
63.18
4744.89.0 × 10−5
1
2
3P → 3P
329
145.532060.1
1.7 × 10−5
0
1
3P → 3P
440
51.82
5785.99.8 × 10−52
1
3P → 3P
163
88.36
3393.0
2.6 × 10−5
1
0
3P
3
Fundamental
parameters
for frequently
observed
and fine structure lines
91
157.74molecules 1900.5
2.1 × 10−6
3/2 → P1/2
3P → 3P
1
2
3P → 3P
Transition
1
0
3P → 3P
1221
3P → 3P01
10
3P → 3P
2 = 1–01
3P → 3P
1 = 2–10
3P
3P
→3–2
3/2 =
1/2

J
J
J
J = 4–3
3P → 3PJ1 = 5–42
3P → 3PJ1 = 6–50
3P → 3PJ2 = 7–61
3P → 3PJ1 = 8–70
J = 1–0
9–8
2–1
JJ == 10–9
J = 3–2
1–0
J = 4–3
2–1
J = 5–4
3–2
J = 6–5
4–3•
J = 7–6
5–4
J = 8–7
6–5•
J = 9–8
7–6
JJ == 10–9
8–7
J = 1–0
9–8

Excitation
188
potential

121.902459.4(K)
70

λ205.18(µm)

ν (GHz)1461.1

228
63

63.18
370.424744.8809.34329
24145.53609.142060.1492.164405.551.82
2601

5785.9115.27

163
16.6

88.36
1300

3393.0230.5491
33.2

157.74867

1900.5345.80

55.3

650.3

461.04188
83.0

121.90520.22459.4576.2770
116.2

205.18433.61461.1
691.4763
154.9

370.42371.7

809.34806.6524
199.1

609.14325.2

492.16921.80

5.5
248.9

2601
289.1

115.271036.9

16.6
304.2

1300
260.2

230.541152.0

33.2
4.25

867
3383

345.8088.63(ref: Carilli
2013)
55.3
650.3& Walter 461.04
12.76
1691
177.26
83.0
25.52

520.2
1128

576.27265.89

116.2
42.53

433.6
845.7

691.47354.51

7.5 × 10−6248.9
119.09

289.1
483.3

1036.9620.30304.2
153.11

260.2
422.9

1152.0708.884.25
191.38

3383
375.9

88.63
797.43

9.4 × 104

3.6 × 103 [⋆]510 [⋆]

2.8 × 103
50 [⋆]

310 [⋆]−6−1 )
Einstein
2.1 × A10(sncrit48(cm[⋆]−3 )

−8
1.7
7.9 × 10−5

9.4 470
× 104

−7
9.0
2.7 × 10−5

4.7
1.2 × 1053−89.8
7.2 × 10−5

3 [⋆]
3
3.6
2.1××1010

2.1
2.5 × 10−6

2.8
3.6 × 1034−5
7.5
1.2 × 10−6

310
1.7
× [⋆]
105

−7
2.6
6.9 × 10−5

6.1 × 10−6−5
2.1 × 10−6

510
1.1
× [⋆]
104
8.750×[⋆]104
2.948×[⋆]105−5
2.7
3.4 × 10−7

1.2
4.5 × 1035

−5
7.2
7.3 × 10−8

2.1
8.7 × 1035−5
2.5
2.4 × 10−6

3.6
2.6 × 1046−57.9
5.1 × 10−8−4
6.9
1.0 × 10−7
−4
6.1
2.3 × 10−6−4
1.2
8.4 × 10−5−3
2.1 × 10−5

[CI] とCO の criticaldensityは同程度 3.4
−3
154.9
371.7
806.6563.80
676.5
443.12
4.1 × 10−5
199.1
325.2
921.8089.32
563.8
531.72
同じ領域から出ている？

4.7 × 105−3
5.1
7.2 × 10−5−2
7.3
1.2 × 10−5−2
1.0
1.7 × 10−4
−2
2.4
2.5 × 10−5−4−2

6.4 470× 105

1.1 × 1046
8.7
1.8 × 1047
1.7
6.8 × 1057
2.9
1.8 × 1058
4.5
3.8 × 1058
6.4
7.1 × 1058
8.7
1.2 × 1059
1.1
1.8 × 1069
2.6
2.5 × 1069
79

[CI] はどこから？

14年12月2日火曜日

[CI] はどこから？

(ref:Shimajiri et al. 2013)
何となく（？）[CI] は PDR 起源だと思われていたがそれでは実際の分布の説明がつかない
14年12月2日火曜日

tive accurate tracer of molecular clouds: the ‘XCI -factor’MNRASL 440, L81–L85 (2014)
MNRASL 440, L81–L85 (2014)

Access publication
20142February
25
Advance
Access publication2014 FebruaryTom
25
Offner,1 ‹†AdvanceThomas
G. Bisbas,
A. Bell3 and Serena Viti2

doi:10.10

doi:10.1093/mnrasl/slu013

omy, Yale University, New Haven, CT 06511, USAs and Astronomy, University College London, Gower Street, London WC1E 6B, UKı́a (CSIC-INTA), Carretera de Ajalvir, km 4, E-28850 Madrid, Spain

An alternative
accurate
tracerof molecular
clouds: the‘XCI -factor’Analternative
accurate
tracerof molecular
clouds:the ‘XCI -factor
2
Stella S. R. Offner,1 ‹†1 Thomas G. Bisbas,2 Tom A.2 Bell3 and Serena
3 Viti2
StellaS.
R.
Offner,‹†ThomasG.
Bisbas,
Tom
A.
Bell
and
SerenaViti
Department of Astronomy, Yale University, New Haven, CT 06511, USA
1

15. Received 2014
January 15; in original form 2013 November 12
12 Department
Department of of
Physics
and Astronomy,
University College
London,CT
Gower
Street,USA
London WC1E 6B, UK
Astronomy,
Yale University,
New Haven,
06511,
23 Department
Centro de Astrobiologı́a(CSIC-INTA),
Carreterade Ajalvir, College
km 4, E-28850
Madrid,SpainStreet, London WC1E 6B, UK
of Physics
and Astronomy,
University
London,Gower
3 Centro de Astrobiologı́a (CSIC-INTA), Carretera de Ajalvir, km 4, E-28850 Madrid, Spain

ABSTRACT

Downloaded from http://mnrasl.oxfordjournals.org/ at University ofAccepted 2014 January 15. Received 2014 January 15; in original form 2013 November 12

We explore the utility of CI as an alternative high-fidelity gas-mass tracer for galactic molecularAccepted
15. theReceived
January
in original
2013 November-factor’for15;
the609 µmform
carbonline, the12analogue of the CO ‘Xclouds. 2014
We January
evaluate‘XCI2014
A BtheSTR
Tdensity to the integrated 12 CO(1–0) line intensity.
factor’, which is the ratio of
HA2 Ccolumn
We explore the utility of CI as an alternative high-fidelity gas-mass tracer for galactic molecularhydrodynamic
simulationsof 609turbulent,star-forming
clouds.
We use 3D-PDR to post-process-factor’fortheµm
carbonline,
theanalogueof the CO ‘Xclouds.AWe
evaluatethe‘X
C
BSTRACT
12 times theand CO
irradiated by 1 and 10
We compare the emissionfactor’,of CI whichis thefor
ratiomodelof the Hclouds
2 column density to the integrated CO(1–0) line intensity.
We explore the utility of CI as an alternative high-fidelity gas-mass tracer for galato post-processhydrodynamic
simulationsof turbulent,star-forming clouds.
We use 3D-PDR
or superior
tracerof the molecularaverage background and demonstratethat
CI is a comparable-factor’
for
the
609
µm
carbonline,
the analogue
clouds.
We
evaluatethe‘X
CI for model clouds irradiated by 1 and
23
−2
I
and
CO
10
times
the
We
comparetheemissionofCgas distribution for column densities up to 6 × 10 cm . Our results hold for both reduced
12column density
to theintegrated
CO(1–0)factor’,which
the ratio ofor superior
tracerof the molecularaveragebackgroundandis
demonstrate
thattheCI isHa2comparableof
3.0
and full chemical networks. For our fiducial Galactic cloud, we deriveanaverage
X
CO
23
−2
cm
.
Our
results
holdfor
reduced star-fo
gas
distributionforcolumndensities
up
to
6
×
10
D
PDR
to
post-processhydrodynamic
simulationsof both
turbulent,
We
use
3
20
−2 −1
−1
21
−2 −1
−1
XCchemical
10 cm
kmGalactics. cloud, we derive an average XCO of 3.0
× 10 cm K km s andI of 1.1 ×and full
networks.
For ourKfiducial
I and COfor model
clouds irradiated by 1 andWecomparetheemission
of
C
20
−2 −1
−1
21
−2 −1
−1
× 10 cm K km s and XC of 1.1 × 10 cm K km s.
a comparable
or superior tracer ofbackgroundand demonstratethat CI –isturbulence
Key words: astrochemistry –averagehydrodynamics– molecular
processes– stars:
23
Key
words:
astrochemistry– hydrodynamics– molecular
processes– turbulence– stars:cm−2. Our results
hold fogas
distributionforcolumndensities
up to 6 × 10
formation – ISM: molecules– photodissociation
region(PDR).
formation
ISM:chemicalmoleculesnetworks.
– photodissociation(PDR).
and–full
For ourregion
fiducial
Galactic cloud, we derive an avera
× 1020 cm−2 K−1 km−1 s and XCI of 1.1 × 1021 cm−2 K−1 km−1 s.
I

I

ION

1 I N T RO D U C T I O N

Key words: astrochemistry– hydrodynamics
molecular
processes – turb
Othermolecules,
HCN,–andgas proxies,
Other molecules, suchas HCN,andsuchgasasproxies,
such
as dustsuch as dust
formation
ISM:
molecules
photodissociation(PDR).
emission– andextinction, provide region
alternativemeans of constraint
emission –andextinction,
providealternative meansof constraint

Within the local Universe, star formation occurs solely in molecualbeit with additional challenges and uncertainties (e.g. Gao &verse,
star formation occurs solely in molecualbeit with additionalSolomon
challenges
and uncertainties
Gaotracer& is atomic
2004; Bolatto
et al. 2011). One(e.g.
promising
14年12月2日火曜日 lar gas. Probing the distribution and dynamics of molecular gas isAbstract• 星形成を探る上で molecular gas の観測は非常に重要• “CO is uniformly adopted by the starformation community to probe moleculargas” -- however XCO has large uncertainty• 流体シミュレーションで X
調べてみる

14年12月2日火曜日

CO と XCI を

Numerical methods••

ORION AMR code (Offner+ 2013)•

600 Msun, NHI ~ 5 x 1021 の分子雲を作る (typical MW cloud)•

ガス密度と速度場を計算

3D-PDR (Bisbas+ 2012)••

post-process で温度分布, chemical network を計算

RADMC-3D••

non-LTE LVG
密度, アバンダンス, 温度分布から, 各領域での CO 及び CI flux を計
算

14年12月2日火曜日

Results

The TheXCI -factor
XCI -factor L83
L83

X factor は非一様

14年12月2日火曜日

Downloaded from http://mnrasl.oxfordjournals.org/ at University of Tokyo Library

their median value. The bottom panel includes all emission; the top only
includes channels
with Tcolumn> 0.1 K.density, fainter material, which is to be expected
for lower
Figure 2. Distribution of log ζ XCO (left) and log ζ XCI (right) for one
since that material is truly a PDR. CO underestimates the emission
view through the simulation for run Rm6_1.0_12_1a (top), Rm6_1.0_12_1f
for lower column
density,
faintermaterial,
which
is to may
be expectedin suchregions;
however,
this faintmaterial
not be detectable
and Rm6_1.0_12_10f(bottom).
are normalized
Figure 2.(middle),
Distributionof log ζ XCO (left)
andThelogX-factors
ζ XCI (right)
for one tofor observations
with lowratio.
since that material
is truly a PDR.
COsignal-to-noise
underestimatesthe emission
their medianvalue, 1/ζ
show a factor (top),of 2 above(thick) and below
view throughthe simulation
for. Contours
run Rm6_1.0_12_1aRm6_1.0_12_1f
Although
six
views
are
shown
for
each
model,
onlyafew
differentin such regions; however, this faint material may not be detectable
the median.
(middle),(thin)
and Rm6_1.0_12_10f(bottom). The X-factors are normalized tolineswithare low
immediately
apparent.
This occurs because most of thefor observations
signal-to-noise
ratio.
their median value, 1/ζ . Contours show a factor of 2 above (thick) and below
domainopticallysuch model,that views
fromoppositesides of the
Although six
viewsisare
shownthinfor each
only
a few
different(thin) the median.
cloud
show
similar
flux.
Views
along
the
three
different
cardinallines are immediately apparent. This occurs because most of the

Downloaded from http://mnrasl.oxfordjournals.org/ at University of Tokyo

Figure 1. Distribution of CO (solid) and CI (dotted) X-factors for six orthogonal views for Rm6_1.0_12_1a. The distributions are normalized to
Figure 1. Distributionof CO(solid)and CI panel(dotted)X-factors
for six ortheir medianvalue.
The bottom
includesall emission;
the top only
thogonal viewsincludes
for Rm6_1.0_12_1a.
The
distributionsarenormalizedtochannels with T > 0.1 K.

Figure 2. Distribution of log ζ XCO (left) and log ζ XCI (right) for one
view through the simulation for run Rm6_1.0_12_1a (top), Rm6_1.0_12_1f(middle), and Rm6_1.0_12_10f (bottom). The X-factors are normalized totheir median value, 1/ζ . Contours show a factor of 2 above (thick) and below(thin) the median.

Resultst University of Tokyo Library on December 1, 2014

density, fainter material, which is to be expected
is truly a PDR. CO underestimates the emission
owever, this faint material may not be detectable
ith low signal-to-noise ratio.
ws are shown for each model, only a few different
tely apparent. This occurs because most of they thin such that views from opposite sides of ther flux. Views along the three different cardinal
fairly similar shaped distributions.
map of the CO and CI X-factors. Perfect coreen column density and emission would yield awever, this is clearly not the case. Sub-structure
cases but are more severe in the CO maps. This is
he column density increasing more strongly thancorrelation between emission and column density
n high-density regions (e.g. star-forming cores)
the gas along the line of sight become opticallyv regions where the CO begins to dissociate. Obpossible to use 13 CO to correct for optical depthsity regions, but this introduces new uncertainties
al. 2010).

ity and FUV field dependence

y short range of column densities for which thendent of density for both tracers. Fig. 3 showsound the mean column density, where CO hapo the fiducial XCO value. In the higher columne X-factor increases strongly with column denan value, the data can be fitted by the functional
αx
H2 . Table 1 gives the best-fitting parameters acleast-squares fit. In Fig. 3, we only include pixels

Figure 3. CI (blue) and CO (black) mean X-factors as a function of H2column density for one view of Rm6_1.0_12_1f (left) and Rm6_1.0_12_10f(right). The means are obtained from the Fig. 2 data by binning the pixels
as a function of their column density. The vertical error bars indicate thestandard deviation and the horizontal error bars indicate the bin size. The
grey lines show the fiducial CO X-factor (horizontal dotted) and the mean
column density (vertical solid). The dashed lines are least-squares best fits tothe data. An online-only figure (Fig. A1) shows the mean WC∗ as a functionof NH2 .

• X factor は NH2 とよく相関• X factor が一定と見なせる領域もある• 密度が低い領域では C1 は CO と comparable• CI のほうが X factor の分散が小さい（？）
MNRASL 440, L81–L85 (2014)14年12月2日火曜日

結局 PDR 仮定はどこが間違っていたのか？

• 分子雲の非一様性• 非一様なら UV photon が染み込みやすくなり, PDR の edge が沢山出来る

• 実際, シミュレーションの結果では ~73% の mass が 0.01 -- 1.0 G の
0radiation を感じている• 今回のシミュレーションに入っていないが CI の relative abundance を上げそうな機構• Cosmic-ray や UV from massive star による CO の破壊• 乱流による mixing• 非平衡化学
14年12月2日火曜日

tute for Computational Cosmology, Durham University, South Rd, Durham DH1 3LE, UK
artment of Physics, Durham
University,
SouthSoc.
Rd,000,Durham
DH1
3LE, UKPrinted 26 July 2013
Mon.
Not. R. Astron.
000–000(0000)(MN LATEX style file v2.2)-Planck Institut fr Astronomie, Knigstuhl 17, D-69117 Heidelberg, Germany
Astronomy Technology Centre, Science and Technology Facilities Council, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJtute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ
versity of Groningen, Kapteyn Astronomical Institute, Landleven 12, 9747 AD Groningen, The Netherlands
I-Planck Institut fr Radioastronomie, Auf dem Hgel 69, 53121 Bonn, Germany
den Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden, The⋆Netherlands

y 2013arXiv:1307.6593v1 [astro-ph.CO] 24 Jul 2013

Using [C ] to probe the Interstellar Medium in z ∼ 2.5
Sub-Millimeter Galaxies

14年12月2日火曜日

S. Alaghband-Zadeh,1 S. C. Chapman,1,2 A. M. Swinbank,3 Ian Smail,3 A. L. R. Danielson,4
R. Decarli,5 R. J. Ivison,6,7 R. Meijerink,8 A. Weiss,9 Paul. P. van der Werf10
1 Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA UK

2 Department of Physics and Atmospheric Science, Dalhousie University, 6310 Coburg Road, Halifax, Nova Scotia, B3H 4R2, Canada

ABSTRACT

3 Institute for Computational Cosmology, Durham University, South Rd, Durham DH1 3LE, UK

We present new [C ](1–0) and 12 CO(4–3) Plateau de Bure Interferometer (PdBI) observations
5 Max-Planck Institut fr Astronomie, Knigstuhl 17, D-69117 Heidelberg, Germanyof five Sub-Millimeter Galaxies (SMGs) and combine these with all available [CI](1–0) lit6 UK Astronomy Technology Centre, Science and Technology Facilities Council, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJerature detections in SMGs to probe the gas distribution within a sample of 14 systems. We
7 Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ
explorethe [CI](1–0) properties of the SMG
population, particularly investigating the ratio of
8 Universityof Groningen, Kapteyn Astronomical Institute, Landleven12, 9747 AD Groningen, The Netherlands
12
9 Max-Planck
theInstitut[CI](1–0)
luminosity
various
COBonn,transition
fr Radioastronomie,
AuftodemHgel 69, 53121
Germanyand far-infrared luminosities. We find that
10 Leiden the
Observatory,
P.O. Box 9513,extend
NL-2300 the
RA Leiden,
Theof
Netherlands
SMGsLeiden
withUniversity,
new observations
spreadL[CI](1−0) /LFIR to much higher values
than found before, with our complete sample providing a good representation of the diversez > 2 SMG population. We compare the line ratios to the outputs of photodissociation region(PDR) models to constrain the physical conditions in the interstellar medium (ISM) of the
26 July 2013
SMGs, finding an average density of ⟨log(n/cm−3 )⟩ = 4.3 ± 0.2 and an average radiation
field (in terms of the local field value, G0 ) of ⟨log(G0 )⟩ = 3.9 ± 0.4. Overall, we find theSMGs are most comparable
to local ULIRGs in G0 and n, however a significant tail of 5
ABSTRACTof the 14 SMGs are likely
best comparedto less
compact,
starburst
galaxies, providing
We present
new [CI](1–0)
and 12CO(4–3) local
Plateaude Bure Interferometer(PdBI) observationsof five
Sub-Millimeter
Galaxiesand distributions
combine theseandwithareall therefore
available [CI](1–0) litnew evidence that many
SMGs
have extendedstar(SMGs)
formation
erature detections
SMGs toWeprobe
the gaswithinofa sampleof 14
not simply scaled up versionsof local in
ULIRGs.
derivethedistribution
ISM propertiesa sampleof systems. We
explore[CI](1–0)
of andthe SMG
population,
quasars also finding thattheythehave
higherproperties
densities
radiation
fieldsparticularly
on averageinvestigating
than the the ratio of
12
I](1–0) luminosity to various CO transition and far-infrared luminosities. We find that
SMGs, consistent withthe
the[Cmore
extreme local ULIRGs, and reinforcing their interpretation as
the SMGs with new observations extend the spread of L[CI](1−0) /LFIR to much higher values
transition objects. We than
explorethebefore,
limitationsof complete
using simple
PDR
modelsto understand[CI],of the diverse
foundwith oursampleprovidinga goodrepresentation
which may be concomitantwith thebulk H2Wemassrather
PDR-distributed.
thereforez > 2 SMG
population.
comparethethanline ratios
to the outputs Weof photodissociation
regionalso assess [CI] as a tracer
H2 , findingthat forour sample
SMGs,inthe
derived(ISM) of the
2 masses medium(PDR)ofmodelsto constrain
the physicalconditions
the H
interstellar
12−3from [CI] are often consistent
with thosedetermined
low excitation
WeandconcludeSMGs, finding
an averagedensity fromof ⟨log(n/cm)⟩ = 4.3CO.
± 0.2
an average radiation(in termsof thelocal
field value,G0 ) gasof ⟨log(G= 3.9 ± 0.4.
Overall, we find thethat [CI] observations fieldprovidea usefultool
to probe
the bulk
and gasoccurring0 )⟩ processes
SMGs
are most
comparable
local ULIRGs
in G0 andhowever atosignificant
tail of 5
within merging SMGs,
howevermore
detailed,toresolved
observationsaren,required
fullyof the 14 SMGs are likely best compared to less compact, local starburst galaxies, providing
exploit [CI] as a diagnostic.
4 Department of Physics, Durham University,
I
South Rd, Durham DH1 3LE, UK

new evidence that many SMGs have extended star formation distributions and are therefore
simply scaled
up versions
local ULIRGs.
We starburst
derive the -ISM
properties
Key words: galaxies:not
evolution- galaxies:
high ofredshift- galaxies:
galaxies:
ISMof a sample ofquasars also finding that they have higher densities and radiation fields on average than theSMGs, consistent with the more extreme local ULIRGs, and reinforcing their interpretation astransition objects. We explore the limitations of using simple PDR models to understand [CI],which may be concomitant with the bulk H2 mass rather than PDR-distributed. We therefore

Abstract• high-z では high-J CO は観測されているが, そこで観ているのはwarm dense gas である• CI のほうが high-J CO よりは H 全体をよくトレースするかもしれ2ない• local ULIRG では CI が H をトレースするのは実証ずみ• high-z SMG では Walter et al. (2011) がこれまでで最大のサンプル数• high-z SMGs でも [CI]/CO や [CI]/FIR は MW と変わらない？
• しかし Walter sample はほとんど全てレンズされているため不
2

定性がある

14年12月2日火曜日

Sample selection & Observation• ５個の un-lensed SMGs at z ~ 2.3 を select• Hα が受かっていて, ALMA から見えるもの• CI(1-0), 12CO(4-3) を IRAM PdBI で観測

4

S. Alaghband-Zadeh et al.

ID

RA

SXDF7 (J0217-0505)
SXDF11 (J0217-0459)
SXDF4a (J0217-0503a)
SXDF4b (J0217-0503b)
SA22.96 (J2218-0021)

02:17:38.92
02:17:25.12
02:17:38.62
02:17:38.62
22:18:04.42

Dec

ztCO(4−3)(hrs)t[CI](1−0)
(hrs)

S2mm
(mJy)

S850µm(mJy)

νobs,CO(4−3)
GHzνobs,[CI](1−0)
GHz-05:05:23.7-04:59:37.4-05:03:37.5-05:03:37.5
00:21:54.4

2.5286[8]2.2821[8]2.0298[2]2.0274[1]2.5169[7]

3.2
3.3
2.1
2.1
3.0

5.1
3.3
7.8
7.8
5.3

0.3±0.1
0.5±0.1
0.4±0.1
0.2±0.1

7.1±1.5
4.5±1.9
2.2±0.85
2.2±0.85
9.0±2.3

130.6
138.5
151.9
151.9
131.1

139.4
148.9
162.2
162.2
139.9

Table 1. SMG positions from the 1.4 GHz detections, and redshifts from the second order moment analysis of the 12 CO(4–3) observations of this work. The
IDs in italics indicate the IDs used for the Hα observations in Alaghband-Zadeh et al. (2012). The 2 mm continuum is measured in the off-line regions of the[CI ](1–0) observations, which are deeper and also at slightly higher frequency than the 12 CO(4–3) observations. The 850 µm fluxes are from Chapman et al.
(2005) and Coppin et al. (2006). The values in brackets in the redshift column represent the error on the last decimal place. Since we detect approximately
equal 2 mm continuum across both SXDF4a and SXDF4b, the S850µm values for SXDF4a and SXDF4b assume the measured 850 µm flux for the wholesystem is equally divided between the two components. We also quote the 5 antennae on-source times (t) and the observing frequencies (ν).

ID

SXDF7
SXDF11SXDF4
SA22.96Beam Size[CI](1−0)

Physical Scale[CI](1−0)

Beam SizeCO(4−3)

Physical ScaleCO(4−3)(arcsec)(kpc)(arcsec)(kpc)

4.4 × 3.5
8.0 × 3.2
5.1 × 2.7
4.8 × 3.2

40 × 3070 × 3040 × 2040 × 30

7.1 × 3.6
4.4 × 3.5
4.4 × 3.3
4.5 × 3.8

60 × 3040 × 3040 × 3040 × 30

Table 2. The beam sizes of the [CI ](1–0) and 12 CO(4–3) observations and the approximate physical scales (in kpc) corresponding to these beam sizes.
14年12月2日火曜日

6

S/N map of SXDF7

S. Alaghband-Zadeh et al.

Figure 1. SXDF7: Top: 12 CO(4–3) spectrum (left) extracted from the peak pixel of the velocity-integrated S/N map (right) marked by a star. The contoursof the S/N map represent the S/N starting at the ±3σ level (solid red for positive σ levels and dashed white for negative σ levels). The noise is derived fromthe standard deviation of the flux outside the velocity channels over which the spectra were integrated to measure the intensities. Bottom: [CI ](1–0) spectrum(left) extracted the pixel marked in the velocity-integrated S/N map (right). The region marked over the spectra represent the velocity channels over which thespectra were integrated to gain the total line fluxes, as determined from the second order moment analysis of the 12 CO(4–3) spectrum (±2σ). The spectra
are centred such that the zero velocity corresponds to the redshift of the 12 CO(4–3) detection. The solid horizontal green lines in the spectra represent thecontinuum level which was subtracted prior to the moment analysis. The green ellipses on the bottom right of the S/N maps represent the beam sizes andshapes. The maps are centred at RA=02:17:38.885 and Dec=-05:05:27.971.

空間分解出来た天体は無し
14年12月2日火曜日

観測結果
まとめ
10 S. Alaghband-Zadeh et al.
L′[CI](1−0)

L′[CI](2−1)

L′CO(4−3)

L′CO(3−2)

L′CO(1−0)

LFIR(1010 K kms−1 pc2 )(1010 K kms−1 pc2 )(1010 K kms−1 pc2 )(1010 K kms−1 pc2 )(1010 K kms−1 pc2 )(1013 L⊙ )SXDF7
SXDF11SXDF4aSXDF4b
SA22.961.3±0.3<1.0
0.7±0.3<0.8
1.2±0.4-

2.9±0.6
1.6±0.3
1.4±0.4
2.0±0.6
2.3±0.6

3.7±0.8
2.0±0.4
1.7±0.5
2.5±0.86±2

7±2
3.9±0.8
3±1
5±2
6±2

0.21±0.05
0.15±0.05
0.09±0.02
0.09±0.02
0.5±0.1111
11J02399J123549
J163650
J163658
J14011
J16359J213511
ID141
MM18423+5938

1.5±0.2
1.4±0.3<1
1.4±0.3
0.7±0.
0.12±0.02
0.69±0.02
0.5±0.2
0.39±0.08

0.5±0.3<0.5<1<1
0.48±0.05
0.043±0.008
0.26±0.01
0.24±0.08
0.26±0.05

3.8±0.5
3.4±0.3
4.6±0.3
3.7±0.5
1.9±0.2
0.33±0.03
0.85±0.01
1.6±0.2
0.95±0.01

4.9±0.6
4.4±0.4
5.9±0.4
4.7±0.6
2.4±0.3
0.42±0.03
1.159±0.009
2.1±0.2
1.20±0.01

8±2 (9±1)
7.5±0.9 (8.4±0.8)
9±1 (11.3±0.8)
10±2 (9±1)
2.4±0.24.5±0.5
0.80±0.08
1.71±0.09 (2.08±0.02)
3.9±0.52.31±0.02

0.7±0.3
0.5±0.2
0.5±0.2
0.7±0.3
0.2±0.1
0.05±0.02
0.23±0.09
0.43±0.02
0.23±0.09

2.5
1
1
1
4
22
32.5
20
20

ID

Table 5. Line luminosities and quoted magnification factors for the SMGs studied in this work (top) and the literature SMG sample (bottom). Where certain 12 CO transition line luminosities are not directly measured the values quoted are inferred from other 12 CO transitions using the conversions from
Bothwell et al. (2013) and are shown in italics. All luminosities are corrected for gravitational lensing using the magnification factors in column (µ). The
far-infrared luminosities are derived from integrating under a modified blackbody curve from 8-1000 µm. The magnification value we use for J14011 is 4 since
the range of possible magnifications is 3–5 (Smail et al. 2005). The magnification value we use for ID141 is 20 since the range of possible magnifications is
10–30 (Cox et al. 2011). Since we detect approximately equal continuum across both SXDF4a and SXDFb, the LFIR values for SXDF4a and SXDF4b assume
that the observed LFIR is divided equally between the two components of this system.

14年12月2日火曜日µ

Using [CI] to probe the Interstellar Medium in z ∼ 2.5 SMGs

luminosity ratios of SMGs

•
•

13

re 8. Luminosity ratios (in units of L⊙ ) of the SMGs
andを持つin the literaturecomparedto the quasar sample with [CI ] detections detailed in
高いin LthisCI work
/ LFIR
SMGs
を新たに発見er et al. (2011). The median values for the complete SMG and quasar samples are marked by the dark red filled star and dark blue filled circle respectively.
SMGs have higher L[CI](1−0) /LFIR and L[CI](1−0)
the literaturesample of quasars. The contours plotted indicate the derived
SFR/Lの割に
gas thanmassが大きいような銀河？
CO(4−3) ratios
s of the gas density (n) and the radiation field (G0 ) for the corresponding ratios of L[CI](1−0) /LCO(4−3) and L[CI](1−0) /LFIR from PDR modeluts as detailed in Section 4.3. However, we note that if only a small fraction of the [CI ] emission is due to the PDRs (Section 4.3.1) then all the ratio values
d be lower than plotted (since the non-PDR contribution to the [CI ] emission should be subtracted from the observed values) therefore suggesting higher
ties and radiation field values for the PDR-related gas. Furthermore, assuming that the [CI ] is non-PDR distributed and instead traces the bulk H2 gas
14年12月2日火曜日
thisplot shows compact starbursts in the low L[CI](1−0) /LFIR and L[CI](1−0) /LCO(4−3) region since the 12 CO(4–3) and far-infrared luminosities

Using [CI] to probe the Interstellar Medium in z ∼ 2.5 SMGs

luminosity ratios of SMGs

13

re 8. Luminosity ratios (in units of L⊙ ) of the SMGs in this work and in the literature compared to the quasar sample with [CI ] detections detailed iner et al. (2011). The median values for the complete SMG andquasar samples
are marked by the dark red filled star and dark blue filled circle respectively.
non-PDRなら左下に動くSMGs have higher L[CI](1−0) /LFIR and L[CI](1−0) /LCO(4−3) ratios than the literature sample of quasars. The contours plotted indicate the derived
s of the gas density (n) and the radiation field (G0 ) for the corresponding ratios of L[CI](1−0) /LCO(4−3) and L[CI](1−0) /LFIR from PDR modeluts as detailed in Section 4.3. However, we note that if only a small fraction of the [CI ] emission is due to the PDRs (Section 4.3.1) then all the ratio values
d be lower than plotted (since the non-PDR contribution to the [CI ] emission should be subtracted from the observed values) therefore suggesting higher
ties and radiation field values for the PDR-related gas. Furthermore, assuming that the [CI ] is non-PDR distributed and instead traces the bulk H2 gas
14年12月2日火曜日
thisplot shows compact starbursts in the low L[CI](1−0) /LFIR and L[CI](1−0) /LCO(4−3) region since the 12 CO(4–3) and far-infrared luminosities•

PDR analysis[C I] in z ∼ 2.5 SMGs

1509

Figure A1. Contours of L[C I](1−0) /LCO(4−3) (solid blue) and L[C I](1−0) /LFIR (dashed green) at various levels of gas density (n) and radiation field (G0 ) fromthe PDR models of Kaufman et al. (1999). The bold contours represent the observed ratios for each of the SMGs with new [C I] detections presented in thiswork. The intersection of the two contours in each case provides a value for n and G0 for the SMG system. The red arrows mark the sources where there is
only a limit to the [C I](1–0) luminosity and therefore we can only gain a lower limit to n and G0 .

14年12月2日火曜日

PDR analysis

Using [CI] to probe the Interstellar Medium in z ∼ 2.5 SMGs

15

Figure 9. The far-UV radiation field, in terms of the local value (G0 ), against the gas density (n) derived from the comparison of various [C I ], 12 CO andfar-infrared luminosities to the outputs from the Kaufman et al. (1999) PDR models. We plot the derived values for the SMGs and the literature quasars. The
median values for the complete SMG and quasar samples are marked by the dark red filled star and dark blue filled circle respectively. We also mark theranges in n and G0 derived for other populations - local ULIRGs, Galactic OB star-formation regions, normal star-forming galaxies and starburst galaxies(Stacey et al. 1991; Malhotra et al. 2001; Davies et al. 2003). We find that the SMGs are most comparable to the local ULIRGs although the tail of 5 SMGs
with lower densities and radiation field values are more consistent with local starburst galaxies.

14年12月2日火曜日

ID

M[CI]
107 M⊙SXDF7
SXDF11SXDF4aSXDF4b
SA22.96
J023991.6±0.4<1.2
0.9±0.3<1.0
1.5±0.5
1.8±0.2

5 DISCUSSION

local ULIRG っぽい
SMGs と,5.1 Physical Interpretation

M[CI] (H2 )109 M⊙MCO (H2 )109 M⊙

We next explore what the derived conditions in the ISM might im<90
39±8
もう少し大人しいが居る
ply forSMGs
the SMG population.
We first note that the density and radi70±2030±10120±3070±20<70110±30130±20

50±20
60±20
80±20

ation field values derived from the comparison to the PDR models
may not represent the true values for these properties and that there
are a number of issues with PDR modelling as described in Sec-

Figure 9. The far-UV radiation field, in terms of the local value (G0 ), against th
far-infrared luminosities to the outputs from the Kaufman et al. (1999) PDR mode
median values for the complete SMG and quasar samples are marked by the dar
ranges in n and G0 derived for other populations - local ULIRGs, Galactic OB s
(Stacey et al. 1991; Malhotra et al. 2001; Davies et al. 2003). We find that the SMwith lower densities and radiation field values are more consistent with local starbu

Gas mass•

励起温度 Tex ~ 30Kを仮定して

ID

M[CI]
107 M⊙

M[CI] (H2 )109 M⊙MCO (H2 )109 M⊙SXDF7
SXDF11SXDF4aSXDF4b
SA22.96
J02399J123549
J163650
J163658
J14011
J16359J213511
ID141
MM18423+5938

1.6±0.4<1.2
0.9±0.3<1.0
1.5±0.5
1.8±0.2
1.8±0.3<1.3
1.7±0.4
0.9±0.2
0.16±0.03
0.87±0.03
0.7±0.2
0.5±0.1

120±30
<90
70±20
<70
110±30130±20130±20<90120±30
70±10
11±2
61±3
50±20
34±8

70±20
39±8
30±10
50±20
60±20
80±20
74±9
90±10
100±2024±3
8.2±0.817.1±0.939±523.1±0.2

carbon mass を導出•

X[CI]/X[H2]~5x10-5 (local value) を仮定して CI mass から H2 を導出•

12CO(1-0) から求めた H2 mass とコンパラ => CI は H2 mass の指標として使える•

ALMA なら CI(2-1) と CI(1-0) を同時に検出して Tex を求められる

Table 7. The neutral carbon masses and molecular gas masses calculated
from the 12 CO(1–0) and [CI ](1–0) luminosities for the SMGs with new[CI ](1–0) observations in this work and the literature sample of SMGs.

c 0000 RAS, MNRAS 000, 000–000⃝

14年12月2日火曜日

まとめ• CI(1-0) と 12CO(4-3)の観測を合わせて SMGs の
ISM の物理状態を探った• SMGs には local ULIRG 的なものも, normal star
forming 的なものも居る• CI と CO を合わせることで PDR model から G

0と n を一意に決められる• CI は H mass のトレーサーとして使える• ただし, PDR model が本当に正しいのかは要検証
214年12月2日火曜日

全体のまとめ• [CI]を観ることで, ISM の物理状態により強い制限が付けられる• [CI]は H mass tracer となりうるが, PDR に代わるモデルを空2間分解した観測で検証する必要あり• CO よりも [CI] の方が明るい場合も？
• SMGs も一枚岩ではない• CI と high-J CO では違うガスを観ている？
• 星形成に関わるガスと関わらないガスを切り分けられれば星形成モデルに制限がつくかも14年12月2日火曜日