Molecular Gas (Excitation) at High Redshift

Fabian WalterMax Planck Institute for Astronomy Heidelberg

A. Weiss (MPIfR) D. Downes (IRAM), D. Riechers (Caltech), C. Carilli (NRAO), F. Bertoldi (AIfA), P. Cox (IRAM), R. Wang (U Peking), E. Daddi (CES), Ran Wang (UA)

Molecular Gas with ALMA and EVLA

CO line SEDs: excitation and structure analysis

multiple components

LVG: n(H2), Tkin –>Tb

S ~ m Ωs bff Tb , m = magnificationΩs bff = r0

2 bff = source filling

CO excitation

free parameters n(H2) Tkin r0

[CO]/[H2]/dv/dr fixed to 10-5 pc (km/s)-1

LVG model degeneracy

well determined:Gas pressure (n T)equivalent radius L’CO(1-0)

Tkin, n(H2) ambiguityBut: shape of the CO SED is temperature dependent!

Solve ambiguity via:Dust (dust temperature, dust to gas mass ratio) Atomic Carbon (Tex)

APM08279 :

log(nH2)=4.2 Tkin=220K r=790pc log(nH2)=4.0 Tkin=350K r= 700pc log(nH2)=5.4 Tkin =40K r=1800pc

Tdust, Tex CI

Dust to gas mass ratio

CO line SED of the MW

COBE (Fixen etal 1999)

CO(1-0)Dame, Hartmann & Thadeus 2001

inner disk

diffusedense

outer diskGC

diffuse

dense

center

Integrated CO SED M82

diffuse

total

M82 CO(1-0)

M82

Walte

r et a

l. 20

03

Weiss e

t al. 2

00

5

molecular gasoutflow. 2005

CO SEDs of local (U)LIRGs:

Two components for all sources; SED peak ~ CO(4-3) Consistent with:LE: Tkin ~ 30 K; n(H2) ~ 10 3.2cm-3 HE: Tkin ~ 50 K; n(H2) ~ 10 4.0cm-3

CO(3-2) APEX2, CO(4-3) FLASH, CO(6-5) CHAMP+, CO(7-6) CHAMPCO(1-0) & CO(2-1) from SEST (Elfhag etal 1996, Aalto etal 1999)

N986; logIR 10.8 N7130 logIR 11.4 Arp186 logIR 11.6

N3256 logIR 11.6 VV114 logIR 11.7 F18293 logIR 11.8 I13120 logIR 12.3

CO line SEDs / Ladders

IRAM 30m CO SED survey(1, 2, 3mm bands)

CO(1-0) Transition: ‘cm’ Telescopes

Riechers, Walter, Carilli et al. 2006

GBT

Effelsberg

PSS J2322 (z=4.1)APM08279 (z=3.9)

+

CO line SEDs at high-z

Cloverleaf F10214 BR1202APM0827

PSS1409 MG0751 RXJ0911

SMM04431HR10

SMM16359BSMM14011

J11148

SMM123549 SMM163650 SMM163658

Tkin ~40 – 60 K (Tdust ~ 50 K)n(H2) ~ 10 3.6-4.3cm-3

Tkin ~ 200 K (Tdust ~ 200 K)n(H2) ~ 10 4.2 cm-3

Strongly lensed (m=80-100) central ~200pc surrounding the QSO. AGNheating!

Normalized high-z CO SEDs

Tkin ~ 30-50 K (Tdust ~ 30-50 K)n(H2) ~ 10 2.7-3.5 cm-3

• All sources ( 8 QSOs & SMGs, 7) are described by a single gas component• CO excitation (peak of the CO SED) in SMGs is lower than in QSO hosts • Molecular gas distributions are compact (r0 = 0.3-1.2 kpc)• Molecualr gas surface densities are high (Msol pc-2

Tkin ~40 – 60 K (Tdust ~ 50 K)n(H2) ~ 10 3.6-4.3cm-3

Tkin ~ 200 K (Tdust ~ 200 K)n(H2) ~ 10 4.2 cm-3

Strongly lensed (m=80-100) central ~200pc surrounding the QSO. AGNheating!

Normalized high-z CO SEDs

Tkin ~ 30-50 K (Tdust ~ 30-50 K)n(H2) ~ 10 2.7-3.5 cm-3

• All sources ( 8 QSOs & SMGs, 7) are described by a single gas component• CO excitation (peak of the CO SED) in SMGs is lower than in QSO hosts • Molecular gas distributions are compact (r0 = 0.3-1.2 kpc)• Molecualr gas surface densities are high (Msol pc-2

Potential effect of galaxy merging on the CO SEDs

LFIR, SFR, n(H2)

M51 Antennae Arp220 Mrk 231

rCO ~ 4kpc rCO ~ 1.5kpc rCO ~ 500 pc rCO ~200 pc

quiet disk galaxies

Early mergers

Advanced mergers & starbursts

AGN heating

z~2 SF gal’s: not extreme starbursts, but massive gas reservoirs

6 of 6 detected in CO, ~10 kpc size Mgas> 1010 Mo ~ high-z HyLIRG

(SMG, QSO host)

But: SFR < 10% HyLIRG

5 arcmin-2 (vs 0.05 for SMGs)

=> common, ‘normal’ high-z galaxies

Daddi ea. 2007, 2008, 2009

Linda’s talk

3.2”

HST

PdBI

CO(2-1)

CO excitation = Milky Way (but Mgas > 10x MW)

LFIR/L’CO = MW << ULIRGs/SMGs

Gas depletion timescales > few x108 yrs

LFIR/L’CO

MW

z~2 SF gal’s: Milky-Way like conditions for SF, not ULIRG-like

BzK-21000 Milky Way

low z

high z

Milky Way

ALMA/EVLA CO discovery space

QSO

ALMA/EVLA CO discovery space

SM

GQ

SO

ALMA/EVLA CO discovery space

CO

NO

T

EXC

ITED

BzK

SM

GQ

SO

…bad news for ISM studies in EoR!

ALMA/EVLA CO discovery space

CO

NO

T

EXC

ITED

BzK

SM

GQ

SO

…bad news for ISM studies in EoR!

TCMB !

ALMA/EVLA CO discovery space

CO

NO

T

EXC

ITED

BzK

SM

GQ

SO

…bad news for ISM studies in EoR!

Freq. of

[CII]

ALMA/EVLA CO discovery space

[CII] resolved at z=6.4

1.9THz line observed at 258 GHzbeamsize: 0.35”, spatially resolved on 2kpc scales

Direct evidence for formation of stellar disk/bulge in host galaxy < 1Gyr after big bang

Bure rocks!

Walt

er

et

al. 0

9

SFRSD=1000 Msun yr-1 kpc-2

C+ at high z

(Walter et al 2009; Maiolino et al 2005, 2009; Iono et al 2006; Bertoldi et al in prep)

Summary

CO observations still workhorse for high-z studies

imaging and high density tracers great.... .....but excitation also provide key information.

distinct differences in high-z galaxy populations

local universe: extremely bright future with Herschel

high-z: ALMA, but still needs quite some observing time.

[CII] will be key diagnostic line for z>7 Universe for ALMA