American Astronomical Society meeting

Co-evolving star formation and AGN activity
within the zCOSMOS density field
John Silverman (ETH-Zurich)
zCOSMOS: S. Lilly (ETH), F. Lamareille (Toulouse), K. Kovac (ETH), V. Mainieri (ESO), G. Zamorani
(INAF-Bologna), O. Le Fevre (LAM-Marseille), T. Contini (LATT-Toulouse), M. Bolzonella (INAFBologna), M. Scodeggio (INAF-Milan) & other zCOSMOS members
XMM/COSMOS: G. Hasinger (MPE), M. Brusa (MPE), V. Mainieri (ESO), Nico Cappelluti (MPE), A.
Finoguenov (MPE), H. Brunner (MPE), A. Comastri (INAF-Bologna), R. Gilli (INAF-Bologna), C.
Vignali (INAF-Bologna) & others
& COSMOS
What drives the concurrent growth of supermassive
black holes and their host galaxy?
• Major mergers of galaxies
Di Matteo et al. 2005, Springel et al. 2005, Croton et al. 2006,
Hopkins et al. 2008
SFRs (data points): Hopkins, A. et al. 2004,
Bouwens et al. 2007
• Internal processs (e.g., bar/disk instabilities, stellar ejecta)
Kormendy & Kennicutt 2004, Davies et al. 2007, Hopkins et al. 2008
• Availability of gas/stochastic processes
Scoville et al. 2003, Kaufmann et al. 2007, Constantin et al. 2008,
Ho et al. 2008, Hopkins et al. 2008
Accretion rate density of AGN*5000
Approach:
How closely is SFR and Maccr related in galaxies hosting AGN?
Does environment play a role? If so, on what scale?
Silverman et al. 2008a, ApJ, 679, 118
See also Boyle & Terlevich 1998, Franceschini,
Hasinger & Miyaji 1999, Merloni, Rudnick,
Di Matteo 2004, Marconi et al. 2004,
Shankar et al. 2008
ETH-Zurich, Bologna, Milan, Marseille, Toulouse, ESO/MPE
zCOSMOS (PI: S. Lilly)
10k VLT/VIMOS spectra (IAB<22.5)
1.7 deg2
5500-9600 Å
z<1.2
~50% completion ‘bright program’
XMM/COSMOS (PI: G. Hasigner)
7543 galaxies
152 AGN
L0.5-10 keV>1042 erg s-1
1848 point sources (Cappelluti et al. 2007, Brusa et al. 2007)
Star formation rates of AGN hosts
[OII]λ3727 as a SFR indicator (Ho et al. 2005)
• Automated routine
zCOSMOS
AGN
- spectral measurements
(Lamareille et al. 2008, 2009-in preparation)
• Removal of AGN contribution:
- [OIII]λ5007 purely AGN dominated
(Kauffmann et al. 2003)
- [OII]AGN/[OIII]AGN=0.2 (Kim et al. 2006)
- AV=0.8 (Kewley et al. 2006)
- At z>0.85, infer [OIII] from correlation with
L2-10 keV (Heckman et al. 2005, Panessa et al. 2006)
SDSS
type 1AGN
• log SFR = log L[OII] - 41 -0.2*MB-3.43
(Moustakis et al. 2006)
Silverman, Lamareille et al. 2009a, ApJ in press
arXiv:0810.3653
Results:
• ~1< SFR < 100 M⊙ yr-1
• Similar evolution to star-forming galaxies
• Evolution consistent with low SFRs in SDSS AGNs (z < 0.3)
Star formation rates of AGN hosts
[OII]λ3727 as a SFR indicator (Ho et al. 2005)
• Automated routine
- spectral measurements
(Lamareille et al. 2008, 2009-in preparation)
• Removal of AGN contribution:
- [OIII]λ5007 purely AGN dominated
(Kauffmann et al. 2003)
- [OII]AGN/[OIII]AGN=0.2 (Kim et al. 2006)
- AV=0.8 (Kewley et al. 2006)
- At z>0.85, infer [OIII] from correlation with
L2-10 keV (Heckman et al. 2005, Panessa et al. 2006)
• log SFR = log L[OII] - 41 -0.2*MB-3.43
(Moustakis et al. 2006)
Silverman, Lamareille et al. 2009a, ApJ in press
arXiv:0810.3653
Results:
• ~1< SFR < 100 M⊙ yr-1
• Similar evolution to star-forming galaxies
• Evolution consistent with low SFRs in SDSS AGNs (z < 0.3)
Co-evolution of SMBHs and their host galaxies
Silverman, Lamareille et al. 2009a, ApJ in press, arXiv:0810.3653
• Constant ratio with redshift
A factor of 10x higher than MBH-Mbulge relation
• <Maccr/SFR> ~ 10-2
• Intermittant scenario with an AGN duty cycle 10x shorter than star formation
Conclusions and further remarks
levels of star formation (1-100 M⊙ yr-1) in zCOSMOS galaxies hosting AGN
- effectively extends SDSS results (Kaufmann et al. 2003, 2007) up to z ~1
- no evidence for quenching attributed to AGN feedback or time delays
• Substantial
•Mutual decline in star formation and supermassive black hole accretion
- shifting a co-evolution scenario to smaller physical scales (i.e., within the same galaxies)
• Intermittant SMBH growth on time scales ~108 yr
What about their environments?
• AGNs reside in environments similar to star-forming galaxies
Silverman, Kovac, Knobel, Lilly et al. 2009b, ApJ in press, arXiv:0812.3402
a short movie ...
K. Kovac,Y. Peng