Molecular Gas at High Redshift

Axel Weiss

MPIfR Bonn

D. Downes, F. Walter, C. Henkel

SMGs with Laboca

30’Laboca:

Wavelength: 870 µmBandwidth: 60 GHz

Resolution: 18.6’’FoV: 10.4’

Pixels: 250Sensitivity: 50 mJy √s

~2mJy rms 100h

High-z Lines : submm observations

@ mm wavelength

z 1-6:

1” ~ 5 - 10Kpc

single pointing determines the total flux density of a galaxy

average source properties

Molecular Gas tracers:

12 CO J >2 transitions

CI (1-0) & (2-1)

CII

HCN (J>2)

CO line SED of the MW

COBE (Fixen etal 1999)

CO(1-0)

Dame, Hartmann & Thadeus 2001

inner disk

diffusedense

outer diskGC

High-z Line Targets (z = 1.4 –6.4):

Source z LFIR(app)

x1013 SL

---------------------------APM08279 3.91 20.0BR1202 4.69 7.1 F10214 2.29 6.0Cloverleaf 2.56 5.9RXJ0911 2.79 5.1MG0751 3.20 4.9SMM16359 2.52 4.5LBQS1230 2.74 3.6VCVJ1409 2.58 3.5LBQS0018 2.62 3.3MG0414 2.64 3.2SMMJ04135 2.85 3.1PSS2322 4.12 3.0BR1335 4.40 2.8SDSSJ1148 6.41 2.7 :SMM14011 2.56 2.0 :HR10 1.44 0.65

Cloverleaf- Bure CO76 PSS2322 VLA CO21

Alloin etal 1997 Carilli etal 2003

Solomon & VandenBout 2005

IRAM 30m CO observations:

14 sources 40 detections (+literature) CO(3-2) to (11-10)

CO line SEDs at high-z

• 13/14 sources are described by a single gas component

•All molecular gas distributions are compact (<1.5kpc)

Cloverleaf F10214

BR1202

APM0827

PSS1409 MG0751 RXJ0911

SMM04431HR10SMM16359BSMM14011

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

diffuse

dense

center

No Evidence for disks/outflows/tidal streams

diffuse

total

M82 CO(1-0)High-z (QSOs):

No evidence for excess flux in J<5-4 transitions compared to the dominant CO component -> no/little gas with H2

densities < 104 cm-3

PSS2322 z=4.1:

Local Merger(s) & ULIRG(s)

Apex CO(4-3)

low density gas

Antennae Almost no data beyond CO(3-2)

Only examples:

Antennae & Mrk231

Mrk231

Papadopoulos etal 2007

Zhu etal 2003

Local starbursts centers:

Similar too high-z QSOs

Tkin ~ 50 - 70 K (Tdust ~ 50 K);

n(H2) ~ 10 4.0cm-3

But: mean CO(3-2)/CO(1-0) ~0.7 for local SB -> presumably due to low excitation gas in the surrounding disks.

Antennae:

low CO excitation in OLR

Tkin ~ 30K, n(H2) ~ 10 3.0cm-3

CO SEDs high and low-z:

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

quite disk galaxies

Early mergers

Advanced mergers & starbursts

AGN heating

Where is the SF gas in the CO SEDs?

Gao etal 2007

Local universe:

H2 densities of HCN emitting volume ~ 105 cm-3

High-z:

HCN observations at high-z extremely difficult and time consuming (IHCN ~ 0.2 ICO), but detected in a few cases.

H2 densities from CO ~ 104 cm-3

Where is the dense gas in the CO SEDs?

Relation to HCN

2 component CO model:

Tkin = Tdust=50K for both

n(H2) ~ 104 cm-3 (ff=85%)

n(H2) ~ 105.1 cm-3 (ff=15%)

PSS2322 z=4.1 GC