High-z Galaxy Formation andSubmm-to-IR emission
Ken NAGAMINE(Osaka Univ.)
長峯健太郎（大阪大学）
2014. 12. 3
1

Outline
1.

What can we study with FIR lines? —>warm & cold neutral gas (WNM & CNM)

2.

How is cold ISM distributed in high-z gal?

3.

Damped Lyα Systems (DLAs)★ DLA-LBG connection, feedback effects

4.

Can we detect high-z DLA gas directly?
★ [CII] 158 µm emission★ predictions for ALMA & Reaching z≳62

Local Galaxies in [CII]Contursi+ ‘02ISO•

Dominant coolant oflate-type gals.

•Neutral ISM in PDRs

[Cii]: 1% of total FIRemission• [Cii]: 40% in diffuse
galactic disk•

e.g., also
Madden+ ‘93
13 (top) and NGC 6946 (bottom) [C ii] contours superposed on the LW2 (6.75 lm) ISOCAM images (Dale et al. 2000). Only the [C ii] fluxMalhotra+ ‘97, ‘01" after background subtraction have been considered for the interpolation. The contour levels for NGC 6946 go from 1.6 to 20 ! 10158
II] goth 0.8 ! 10 ergs s cm sr Contour:spacing. For NGC [C1313 theyfrom 1.8µmto 9.5 !line
10 ergs emission
s cm sr with a 0.4 ! 10 ergs s cmLeech+ ‘99"6"1"2"1"6"1"2"1"6"1"6"2

Image: 5-8 micron ISOCAMlm band, !f! (5–10 lm), by multiplying the(5–8.5 lm) flux by a scale factor of 1.7 (seehand the [C ii]/!f!(5–10 3lm) ratio is quite constant for alarge range of radiation fields (Helou et al. 2001; Fig. 4,

PDRs (photo-dissociation regions)•Regions in which the chemical andheating processes are dominated or
induced by interaction with FUVphotons•[O i] 63µm and [C ii] 158µm emission
from the neutral ISM arises in PDRs

Draine book4Gorti & Hollenbach ‘02

Why [CII]?
•Dominant coolant of MW-like late-type gals.
N(Cii*)•••

Complementary to opt-IR (cf. LBG@z~3)
A new window for high-z SF using DLAs—> use [Cii] to infer SFR
Cosmological galaxy formation study withALMA

5C+nΛ[C II ] ~ NN((CHIII*)) hν 21 A21(Pottasch+’79; Wolfe+ ‘03)

DLAs:28 Jul 2005 16:32

ARAR251-AA43-20.tex

XMLPublishSM (2004/02/24)☀ quasar

P1: KUVDAMPED Lyα SYSTEMS

873

Lanzetta et al. ‘95
Storrie-Lombardi & Wolfe ‘00

Gas density

DLAs dominate Hi massdensity at z~3. Downloaded from arjournals.annualreviews.org
go on 08/29/05. For personal use only.

NHI > 2 × 1020 cm−2

MgII systems

DLAs

6Figure 5 Neutral gas mass density versus z from Prochaska et al. (2005). H I data at

Annu. Rev. Astro. Astrophys. 2005.43:861-918. Downloaded from arjournals.annualreviews.org
by University of California - San Diego on 08/29/05. For personal use only.

The survey statistics cited above refer only to systems with N(H I) ≥ 2 ×1020 cm−2 , which is a historical threshold set by the H I properties of nearby
spiral galaxies (see Section 1.1). Because the nature of damped Lyα systems isstill not understood, their H I properties may differ from those of nearby H I disks:
for example, CDM cosmogonies envisage damped Lyα systems as merging protogalactic clumps (Haehnelt, Steinmetz & Rauch 1998). As a result, it is reasonableto ask whether the 2×1020 cm−2 threshold is the appropriate one. Indeed, since theempirically determined frequency distribution of H I column densities increases
with decreasing N(H I) (see Figure 3), lower H I thresholds would be advantageous
because they would result in larger samples.

DLA Statistics

HI column density distribution

Figure 3 The N (HI) frequency distribution f (N , X ) determined by Prochaska, HerbertFort & Wolfe (2005) for all damped Lyα systems in the SDSS-DR3 4 sample. Overplottedon the data points are a single power-law, "-function, and a double power-law. Only thelatter two are acceptable fits to the data. Plot taken from Prochaska, Herbert-Fort & Wolfe(2005).

Prochaska+’14

Prochaska+ ‘05 SDSS DR3>500 DLAs
Wolfe+ ‘05 ARA&A

Strong constraint forstructure formation sims
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DLAs in Cosmological Simulations
NHIMstar

MZ~100kpc physz=3SFRDLAs

UVB

local stellar radiation
8

metallicity

KN04a,b

The `New’ Picture of DLAs @ high-z(vs. the `old’ picture of simple massive galactic disk)
Mhalo ∼ 1012−13 M⊙

LBG
UV backgroundJνDLAsΣν ★

Σν ∝ ψ̇∗(cf. solves Z-problem too.)(cf. Brisbin+’14)
9☀ quasarRubin+ ‘14@ high-z

CGM(Hennawi+)☀ quasar•

Probing CGM (circum-galactic medium) around DLAs using QSO pairsight-lines•

40 DLAs at 1.6<z<3.6•

the second quasar sightline probes Lyα, Cii, Si II, and Civ absorption inthe CGM transverse to the DLA to projected distances R⊥ < 300kpc.

•Covering fraction of optically thick Hi (NHI > 1017.2 cm−2) ≈ 30% withinR⊥ < 200 kpc of DLAs.

•DLAs arise close to the centers of their host halos rather than on theiroutskirts.

•So maybe our clumpy CNM picture for DLA is not so bad after all…
10(cf. Brisbin+’14)

How can we compute [Cii]emission in cosmologicalhydrodynamic simulations?

11Multi-phase ISM model
backgroundJνρ0 , V 0ψ̇⋆★

CNM
T~100 KFUV radiationfM , fVΣνρc( n ∼ 10 cm−3 )

(LBG)

WNM
T~8000 K

CNM preferred for DLAs
(Wolfe+ ‘03b; Howk+ ‘05)

McKee & Ostriker ‘77
Wolfire+ ‘95
Wolfe+ ‘03

ρw ( n ∼ 0.1 cm−3 )12CNM mass fraction
ρC V C + ρW V W = ρ0 V 0(CNM)(mass conservation)(WNM)

VC + VW = V0

ρC V CfM ≡ρ0 V 0(volume conservation)(CNM mass fraction)

1 − (ρW /ρ0 )=
1 − (ρW /ρC )Given ρ0 , ρC , ρW ,fM
KN+ ’0613

density, n (see Fig. 3a), the regions of thermal stability
occur where @ðlog PÞ=@ðlog nÞ > 0 (in the case of constant
C). Thus, a two-phase medium in which a WNM can

Phase Diagram

which is ins
cm$3. Thisshown) whe

Equilibrium:Γ = nΛ

[CII] cooling rate per H atom
(dotted line)ℓCII : spontaneous [Cii]energy emission rate
Wolfe+ ‘03

Fig. 3.—Two-phase diagrams for gas heated by grain photoelectric emission plus cosmic rays a
$1$2
M& yr
14 kpc , metallicity ½C=H# ¼ $1:5, and dust-to-gas ratio log10 ! ¼ $1:7. (a) Pressure v
medium. Labels and horizontal line in the (n, P)-plane are explained in the text. (b) Fractiona

[CII] Flux Density vs. Halo mass– 35 –(1 + z)LνSν =,24πdLLν =(no wind)vc =Sν ≈ C2

ν158!

!

LCII!v "GMr200cc

2/3

0.6

"1/2

Mhalo
1012 h−1 M⊙

C2 = 0.6 mJy∝ Mhalocircular velocity"2/3mJy,(no feedback)C2 = 0.06 mJy (strong feedback)(strong wind)

KN+ ’06
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Cumulative [Cii] Flux Density PDF– 37 –(Gadget-3 cosmological SPH simulations)(strong feedback)(no feedback)30%
3%
KN+ ’06

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Fig. 12.— Cumulative probability distribution of [C ii] sources as a function of flux density

Estimates for Actual DLA galaxies
Band 7Band 8

ALMA 20 hr integration
1-sigma sensitivity(Moller+ ‘02)

(Waiting for Cycle 2 obs)

redshift desert(atmospheric window)
Redshift17

Vallini+ ‘13•

Cosmo sim (Gadget-2) +postprocess RT (LICORICE) +subgrid multi-phase ISM model•

But no metal-cooling, SF & feedbackin the original sim —> gas distunreliable.

•z=6 gal (≈Himiko-like LAE)•

[Cii] peak offset from galaxy by ~100km/s; f~185 mJy km/s (for Z=Z⦿);
95% from CNM, 5% from WNM•[Oi] 63µm, [Nii] 122µm much weaker
than [Cii]18

Towards z>619

Yajima+ ‘14(Romano-diaz+’13 sim.)•Gadget-3 cosmo sim w/ fullphysics + dust model +postprocess RT•

Constrained realization of 5-𝜎
density peak ≈ quasar
environment at z>61Mpc/h•

30 pc (phys) resol. @ z=92 kpc

20z=6.3

Yajima+ ‘14

Very high SFR
The most massive galaxy:
Mstar ∼ 8.4 × 1010 M⊙ ,Mdust ∼ 4.1 × 108 M⊙,
SFR ∼ 745 M⊙ yr−1 (z = 6.3)

Sub-solar metallicity
Large amount ofdust in massive gals

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UV: 1600 A rest-frame

IR: 106 µm rest (850 µm obs)
surface brightness in the log scale in unitsof erg s−1 cm−2 Hz−1 arcsec−2 .

Yajima+ ‘14
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Conclusions•[Cii] emission & DLAs give us useful insights
on ISM in high-z gals.

•DLAs could be clumpy CNM gas.

•Dominance of faint galaxies for DLAs: ageneric prediction of a CDM model•

Most massive gals at z≳6 can be observedwith ALMA if we know where to look.

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