an iram pdbi co survey of luminous submm galaxies a spearhead project for alma ida meeting,...
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An IRAM PdBI CO Survey of Luminous Submm Galaxies
A spearhead project for ALMA
IDA Meeting, Copenhagen 20-21 Dec. 2004
Thomas R. Greve (Caltech)R. Genzel (MPE),R. J. Ivison (ROE),R. Neri (IRAM),I. Smail (Durham),S. Chapman (Caltech),A. W. Blain (Caltech),F. Bertoldi (MPIfR),L. Tacconi (MPE),P. Cox (Orsay),A. Omont (AIP)
Outline A Brief History of CO at high z
Why CO? High-z CO detections to date
An interferometric CO survey of (sub)mm galaxies (SMGs) Duty cycle and current status Bulk gas properties of SMGs Comparison with ULIRGs Implications for galaxy formation models
Conclusions and future directions
IDA Meeting, Copenhagen 20-21 Dec. 2004
High-z CO detections to date
IDA Meeting, Copenhagen 20-21 Dec. 2004
• 13 QSOs, including IRAS F10214+4714 the first ever high-z CO detection (Brown & Vanden Bout 1991)
• 6 High-z Radio Galaxies (HzRGs)
• 1 Lyman Break Galaxy (LBGs)
High-z CO detections to date
IDA Meeting, Copenhagen 20-21 Dec. 2004
Omont et al. (1996)
z=4.69
• 13 QSOs, including IRAS F10214+4714 the first ever high-z CO detection (Brown & Vanden Bout 1991)
• 6 High-z Radio Galaxies (HzRGs)
• 1 Lyman Break Galaxy (LBGs)
High-z CO detections to date
IDA Meeting, Copenhagen 20-21 Dec. 2004
De Breuck et al. (2003)
z=3.52
• 13 QSOs, including IRAS F10214+4714 the first ever high-z CO detection (Brown & Vanden Bout 1991)
• 6 High-z Radio Galaxies (HzRGs)
• 1 Lyman Break Galaxy (LBGs)
Omont et al. (1996)
z=4.69
High-z CO detections to date
IDA Meeting, Copenhagen 20-21 Dec. 2004
Baker et al. (2003)
z=2.73
• 13 QSOs, including IRAS F10214+4714 the first ever high-z CO detection (Brown & Vanden Bout 1991)
• 6 High-z Radio Galaxies (HzRGs)
• 1 Lyman Break Galaxy (LBGs)
De Breuck et al. (2003)
z=3.52
Omont et al. (1996)
z=4.69
High-z CO detections to date
IDA Meeting, Copenhagen 20-21 Dec. 2004
Omont et al. (1996)
De Breuck et al. (2003)
Baker et al. (2003)
• 13 QSOs, including IRAS F10214+4714 the first ever high-z CO detection (Brown & Vanden Bout 1991)
• 6 High-z Radio Galaxies (HzRGs)
• 1 Lyman Break Galaxy
• QSOs+HzRGs show strong CO emission from extended (~10kpc) starburst regions
• Typical gas and dynamical masses of ~1x1011Mo
• Co-eval growth of stellar bulges and massive black holes
• Rapid enrichment before z~7
High-z CO detections to date
IDA Meeting, Copenhagen 20-21 Dec. 2004
Omont et al. (1996)
De Breuck et al. (2003)
Baker et al. (2003)
• 13 QSOs, including IRAS F10214+4714 the first ever high-z CO detection (Brown & Vanden Bout 1991)
• 6 High-z Radio Galaxies (HzRGs)
• 1 Lyman Break Galaxy
• QSOs+HzRGs show strong CO emission from extended (~10kpc) starburst regions
• Typical gas and dynamical masses of ~1x1011Mo
• Co-eval growth of stellar bulges and massive black holes
• Rapid enrichment before z~7
However, most high-z CO detections are a mixed bag of non-uniformly selected (and often strongly lensed) QSOs and HzRGs
High-z CO detections to date
IDA Meeting, Copenhagen 20-21 Dec. 2004
Omont et al. (1996)
De Breuck et al. (2003)
Baker et al. (2003)
• 13 QSOs, including IRAS F10214+4714 the first ever high-z CO detection (Brown & Vanden Bout 1991)
• 6 High-z Radio Galaxies (HzRGs)
• 1 Lyman Break Galaxy
• QSOs+HzRGs show strong CO emission from extended (~10kpc) starburst regions
• Typical gas and dynamical masses of ~1x1011Mo
• Co-eval growth of stellar bulges and massive black holes
• Rapid enrichment before z~7
However, most high-z CO detections are a mixed bag of non-uniformly selected (and often strongly lensed) QSOs and HzRGs.
SMGs: 2+1 sources detected in CO prior to our survey.
L1L2
R.A. (2000)
Dec
. (20
00)
SMMJ02399-0136 (z=2.81)
velocity offset (km/s)
-1000 -500 0 500
flux density (Jy/beam)
-0.001
0.000
0.001
0.002
0.003
0.004
0.005
1-0.001
0
0.001
0.002
0.003
0.004
-1000 -500 0 500 1000
40
80
120
160
50 100
-6 -4 -2 0 2 4 6
-500
0
500
Ivison et al. 1998, MNRAS 298, 583Frayer et al. 1998, ApJ, 506, L7Genzel et al. 2003, ApJ, 584, 633
Mdyn(R<8kpc) ~ 2-3x1011 MO
Most of which is baryonic
IDA Meeting, Copenhagen 20-21 Dec. 2004
SMMJ14011+0252 (z=2.51)
Ivison et al. 2001 ApJ 561, L45Frayer et al. 1999, ApJ, 514, L13Downes & Solomon 2003 ApJ 582, 37
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGs(Genzel, Ivison, Neri, Bertoldi, Blain, Chapman, Cox, Greve, Neri, Omont, Smail,
Tacconi)
We are undertaking a first systematic CO survey of dust-enshrouded starburst galaxies at high redshifts
Bright (S850>5mJy) submm-selected galaxies detected in the radio. This population is responsible
for ~25% of the submm background.
IDA Meeting, Copenhagen 20-21 Dec. 2004
Duty-cycle and current status:
• SCUBA/MAMBO sources with VLA 1.4GHz counterparts (Lockman E, ELAIS N2, SSA 22, SSA13, HDF-N etc).
• Keck follow-up spectroscopy with LRIS-B: ~70 redshifts, <z>=2.4
We are undertaking a first systematic CO survey of dust-enshrouded starburst galaxies at high redshifts
An IRAM PdBI CO Survey of SMGs(Genzel, Ivison, Neri, Bertoldi, Blain, Chapman, Cox, Greve, Neri, Omont, Smail,
Tacconi)
IDA Meeting, Copenhagen 20-21 Dec. 2004
Keck (LRIS-B + NIRSPEC) spectroscopy
Chapman et al. (2003)
Ivison et al. (2002)
IDA Meeting, Copenhagen 20-21 Dec. 2004
Duty-cycle and current status:
An IRAM PdBI CO Survey of SMGs
• SCUBA/MAMBO sources with VLA 1.4GHz counterparts (Lockman E, ELAIS N2, SSA 22, SSA13, HDF-N etc).
• Keck follow-up spectroscopy with LRIS-B: ~70 redshifts, <z>=2.4
• PdBI follow-up for redshift confirmation (2-3 tracks each)
• High-resolution PdBI follow-up for spatially resolved CO dynamics
IDA Meeting, Copenhagen 20-21 Dec. 2004
Duty-cycle and current status:
• SCUBA/MAMBO sources with VLA 1.4GHz counterparts (Lockman E, ELAIS N2, SSA 22, SSA13, HDF-N etc).
• Keck follow-up spectroscopy with LRIS-B: ~70 redshifts, <z>=2.4
• PdBI follow-up for redshift confirmation (2-3 tracks each)
• High-resolution PdBI follow-up for spatially resolved CO dynamics
• Status winter 2004: 7 (+1) new CO detections, 6 non-detections - the number of SMGs detected in CO almost tripled!
An IRAM PdBI CO Survey of SMGs
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGs
First results Neri et al. (2003)
z=2.509 z=3.349 z=2.380
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGs ID Transition zspec zCO FWHM ICO
Our Detections km/s Jy km/sSMMJ02396-0134 (2-1) 1.062+-0.001 1.062+-0.002 780+-60 3.4+- 0.3SMMJ13120+4242 (4-3) 3.405+-0.001 3.408+-0.002 530+-50 1.7+- 0.3 SMMJ16366+4105 (3-2) 2.454+-0.001 2.450+-0.002 870+-80 1.8+- 0.3SMMJ16371+4053 (3-2) 2.374+-0.001 2.380+-0.004 830+-130 1.0+- 0.2 SMMJ22174+0015 (3-2) 3.098+-0.002 3.099+-0.004 780+-100 0.8+- 0.2 SMMJ04431+0210 (3-2) 2.5092+-0.0008 2.5094+-0.0002 350+-60 1.4+-0.2SMMJ09431+4700 (4-3) 3.349+-0.001 3.3460+-0.0001 420+-50 1.1+-0.1 SMMJ16368+4057 (3-2) 2.380+-0.002 2.3853+-0.0014 840+-110 2.3+-0.2 (7-6) . . . 2.383+-0.002 . . . 1.1+- 0.2Non-detectionsSMMJ10523+5722 (3-2) 2.611+-0.001 2.5901 - 2.6119 . . . < 0.5SMMJ10524+5724 (3-2) 3.036+-0.001 3.0593 - 3.0318 . . . < 0.8SMMJ12360+6210 (3-2) 1.994+-0.001 1.9865 - 2.0015 . . . < 0.9SMMJ13123+4239 (3-2) 2.320+-0.001 2.3115 - 2.3300 . . . < 1.0SMMJ16363+4055 (3-2) 2.283+-0.001 2.2676 - 2.2919 . . . < 0.4
SMMJ16363+4056 (2-1) 1.495+-0.001 1.4802 - 1.5001 . . . < 0.8 Literature sourcesSMMJ02399-0136 (3-2) 2.803+-0.003 2.808+-0.002 710+-80 3.0+- 0.4 (3-2) . . . 2.8076+-0.0002 >1100 3.1+-0.4SMMJ14011+0252 (3-2) 2.562+-0.002 2.5653+-0.0003 200+-40 2.4+-0.3 (3-2) . . . 2.5652+-0.0001 190+-11 2.8+-0.3 (7-6) . . . 2.5651+-0.0002 170+-30 3.2+-0.5SMMJ16359+6612 (3-2) 2.5165+-0.0015 2.5168+-0.0003 500+-100 3.5+-0.1 (3-2) . . . 2.5174+-0.0002 500+-100 2.50+-0.12EROJ16450+4626 (2-1) 1.443+-0.001 1.439+-0.001 400+-20 1.40+-0.10 (5-4) . . . 1.440+-0.001 380+-20 1.35+-0.10 (1-0) . . . . . . . . . 0.6+-0.1
IDA Meeting, Copenhagen 20-21 Dec. 2004Greve et al. (2005)
Greve et al. (2005) Genzel et al. (2003) Neri et al. (2003)
Downes & Solomon (2003)
An IRAM PdBI CO Survey of SMGs
Neri et al. (2003) Greve et al. (2005)
z=1.062 z=2.803
z=2.562z=3.405z=3.349
z=2.509
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGs
Neri et al. (2003) Kneib et al. (2004) Greve et al. (2005)
Greve et al. (2005) Andreani et al. (2000) Greve et al. (2005)
Greve et al. (2005)
z=2.380 z=2.517 z=2.454
z=3.098z=1.439z=3.098
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGs
7 (+1) out of 13 (+1): detection rate of 54-57%. Remarkably good - comparable to the radio-ID fraction.
This confirms the <z>=2.4 redshift distribution of the bright, radio-detected SMG population (Chapman et al. 2003).
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGs
7 (+1) out of 13 (+1): detection rate of 53-57%. Remarkably good - comparable to the radio-ID fraction.
This confirms the <z>=2.3 redshift distribution of the bright, radio-detected SMG population (Chapman et al. 2003).
Greve et al. (2005)
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGs
7 (+1) out of 13 (+1): detection rate of 54-57%. Remarkably good - comparable to the radio-ID fraction.
This confirms the <z>=2.4 redshift distribution of the bright, radio-detected SMG population (Chapman et al. 2003).
H provides much more reliable estimate of the systemic (CO) redshift:
V(CO-Ly) V(CO-H) blueshifted: 5 0 redshifted : 2 0 zero offset : 1 4
IDA Meeting, Copenhagen 20-21 Dec. 2004
Greve et al. (2005)
An IRAM PdBI CO Survey of SMGs
Bulk gas properties:
CO luminosity:
<LCO>=(3.8+-2.0)x1010K km/s 4x ULIRGs Gas masses (including HI+He):
<Mgas>=(3.0+-1.6)x1010MO
4x ULIRGs
So SMGs contains 3-4x more gas than local ULIRGs. Depletion of Gas as the merger progresses(Gao et al. 1999)?
Detection rate: z>2.4 : 5/7 (71%) z<2.4 : 2/6 (33%)Is this evidence for evolution in gas mass content?
IDA Meeting, Copenhagen 20-21 Dec. 2004
Starformation efficiency:
• SMGs extend the (non-linear) FIR-CO correlation to higher z and luminosities
SMGs:
<LFIR/LCO>=(450+-170) LO MO-1
ULIRGs:
<LFIR/LCO>=(180+-130) LO MO-1
• Starformation efficiency might be higher in SMGs than in ULIRGs
• Tentative evidence of a FIR-CO correlation within the SMG sample itself
An IRAM PdBI CO Survey of SMGs
log(LCO) = 0.6 log(LFIR) + 2.4
Greve et al. (2005)
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGs
Starformation efficiency:
• SMGs extend the (non-linear) FIR-CO correlation to higher z and luminosities
SMGs:
<LFIR/LCO>=(450+-170) LO MO-1
ULIRGs:
<LFIR/LCO>=(180+-130) LO MO-1
• Starformation efficiency might be higher in SMGs than in ULIRGs
• Tentative evidence of a FIR-CO correlation within the SMG sample itself
Greve et al. (2005)
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGsDynamical masses:
• The double horn profiles are indicative of ordered orbital motion: either circum-nuclear disk or a merger.
• Assuming: 1) a conservative source size of D=0.5” (~3.7kpc at z=2.3) 2) random orbital inclinations (factor of /4) 3) Merger model*
<Mdyn>SMG = (1.2+-1.5) x 1011MO
* Toomre stability criterion:
Q = vs G 1 for a gaseous disk to be stable.
We find Q << 1 for Mgas=3x1010MO and R~4kpc.
IDA Meeting, Copenhagen 20-21 Dec. 2004
Greve e al. (2005)
An IRAM PdBI CO Survey of SMGs
Dynamical masses:
• Velocity dispersion of SMGs is comparable to that of HzRGs and 3-4x that of ULIRGs.
• Assuming Mdyn ~ R2, andULIRGs:
Mdyn(R<0.6kpc) ~ 6x109MO,we findSMGs:
Mdyn(R<0.6kpc) ~ 4x1010MO
• The large line widths of SMGs strongly suggest that they are massive systems - with Mdyn comparable to HzRGs.
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGsGas mass fractions:
• Gas fraction:
SMGs : Mgas/Mdyn ~ 0.3
ULIRGs: ~ 0.16 (Downes & Solomon 1998)
• So SMGs appear to be more gas-rich than local ULIRGs, although
this is subject to uncertainties in the CO-H2 conversion factor and dynamical mass estimates.
But overall there is mounting evidence that SMGs are neither high-z replicas of local ULIRGs, nor simply scaled up versions.
Rather SMGs are more gas-rich and seem to form stars more efficiently (caveat: CO doesn’t trace the dense starforming gas, HCN does!)
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGsGas consumption time-scale and baryonic masses:
• The median starformation rate is <SFR>=720 MO yr-1, hence the duration of the ‘SCUBA/MAMBO’-phase is:
= M(H2)/SFR ~ 40Myr
• This is a lower limit since it assumes continuous starformation and ignores negative feedback and the possibility of HI falling in from outer regions.
IDA Meeting, Copenhagen 20-21 Dec. 2004
An IRAM PdBI CO Survey of SMGsGas consumption time-scale and baryonic masses:
• The median starformation rate is <SFR>=720 MO yr-1, hence the duration of the ‘SCUBA/MAMBO’-phase is:
= M(H2)/SFR ~ 40Myr
• This is a lower limit since it assumes continuous starformation and ignores negative feedback and the possibility of HI falling in from outer regions.
• The median V-band restframe luminosity is 2 x 1011LO, which implies
median stellar mass of M* ~ 3 x 1010 MO (Smail et al. 2004).
So the typical baryonic mass is Mbar ~ 6 x 1010 MO - comparable to the masses of local L* galaxies. And SMGs are baryon-dominated in their
inner regions: Mbar/Mdyn ~ 0.5. Assembling that much baryonic matter so early is a severe challenge for models!
IDA Meeting, Copenhagen 20-21 Dec. 2004
Implications for Models of Galaxy Formation
Greve et al. (2005)
A fundamental test-bed for galaxyformation models is the assemblyof massive baryonic galaxies.
Co-moving number density of
Mbar = 6 x 1010MO is
n(M>Mbar) ~ 5 x 10-6 Mpc-3
Corrected for our CO detection Fraction (0.53) and finite surveyvolume.
IDA Meeting, Copenhagen 20-21 Dec. 2004
Implications for Models of Galaxy Formation
A fundamental test-bed for galaxyformation models is the assemblyof massive baryonic galaxies.
Co-moving number density of
Mbar = 6 x 1010MO is
n(M>Mbar) ~ 5 x 10-6 Mpc-3
Corrected for our CO detection Fraction (0.53) and finite surveyvolume.
This is a lower limit since we mustcorrect for the finite life time ofSMGs:
(2.0-3.5)/SMG = 1.5Gyr/(40-200)Myr = 8-38
1011
Mo
7x1010
Mo
5x1010
Mo
Greve et al. (2005)
High-resolution PdBI observations of SMGs
- a taste of ALMA
IDA Meeting, Copenhagen 20-21 Dec. 2004
Tacconi et al. in prep.
1.3mm continuum, beam 0.7”x0.6”
SMMJ09431+4700: H6 + H7 (both radio sources) are part of the same
physical structure - separation 22kpc
IDA Meeting, Copenhagen 20-21 Dec. 2004
Tacconi et al. in prep.
SMMJ09431+4700:
CO(4-3) is detected in H7
(but not H6).
Tentative evidence for a
blueshifted filament of gas
between H7+H6.
High-resolution PdBI observations of SMGs
- a taste of ALMA
IDA Meeting, Copenhagen 20-21 Dec. 2004
Tacconi et al. in prep.
SMMJ09431+4700:
CO(4-3) is detected in H7
(but not H6).
Tentative evidence for a
blueshifted filament of gas
between H7+H6.
We have ‘tasted’ what we
might expect to achieve
with ALMA!
High-resolution PdBI observations of SMGs
- a taste of ALMA
IDA Meeting, Copenhagen 20-21 Dec. 2004
Tacconi et al. in prep.
SMMJ163681+4057:
High-resolution PdBI observations of SMGs
- a taste of ALMA
The Future…
IDA Meeting, Copenhagen 20-21 Dec. 2004
• CO is great! But…
• It doesn’t trace the dense starforming gas
• Need high-density tracers such as HCN
• Other molecular/atomic lines, e.g. CI
• Ultimate goal: detail ISM studies at high-z as well as ‘blind’ CO surveys.
…is here and it’s interferometrical!
The Future…
IDA Meeting, Copenhagen 20-21 Dec. 2004
…is here and it’s interferometrical!• CO is great! But…
• It doesn’t trace the dense starforming gas
• Need high-density tracers such as HCN
• Other molecular/atomic lines, e.g. CI
• Ultimate goal: detail ISM studies at high-z as well as ‘blind’ CO surveys