AEGIS-X: Results from the Chandra survey of the Extended Groth Strip
Elise LairdA Georgakakis (NOA), K Nandra (PI: Imperial), J Aird (Imperial), D Croton (Berkeley), K Bundy (U Toronto), A Coil (Steward), C Pierce (UCSC), and the AEGIS team
The X-ray Universe 2008, Granada
All Wavelength Extra-Galactic International Survey
• Deep multiwavelength data
• Wide area (~0.5 -1.0 deg2)
• Keck/DEIMOS DEEP2 spectroscopy: >10,000 redshifts with R<24.1, mainly 0.6<z<1.4
Palomar
GALEX
Chandra HST/ACS
aegis.ucolick.org; Davis et al. (2007)
The X-ray Universe 2008, Granada
AEGIS-X survey
• 1.6 Ms over 0.67 deg2
(8 ACIS-I pointings)• Flux limits (1%
complete);– SB (0.5-2 keV) 5.3 x 10-17
cgs– HB (2-10 keV) 3.8 x10-16 cgs
• 1325 sources, selected between 0.5 and 7 keV
• <1.5% spurious sources• 0.79” astrometric
accuracyLaird et al. submitted to ApJS
The X-ray Universe 2008, Granada
AEGIS-X survey
• 1.6 Ms over 0.67 deg2
(8 ACIS-I pointings)• Flux limits (1%
complete);– SB (0.5-2 keV) 5.3 x 10-17
cgs– HB (2-10 keV) 3.8 x10-16 cgs
• 1325 sources, selected between 0.5 and 7 keV
• <1.5% spurious sources• 0.79” astrometric
accuracy
AO9: additional 1.8 Ms over 0.2 deg2
Reduced data, data products, catalogues publicly available at http://astro.imperial.ac.uk/research/aegis
Laird et al. submitted to ApJS
The X-ray Universe 2008, Granada
AEGIS-X survey
• Using Maximum Likelihood technique to find secure counterparts: – optical: 76%, complete to
RAB=24.1, 6% spurious matches
– IRAC 3.6m: 94% (of sources with coverage), complete to mAB=23.8, 1% spurious matches
• Currently ~35% spectroscopic completeness (with DEEP3 60%)
---- L* at z=1
Spectroscopy: • Keck/DEEP2 (Davis et al. 2003)• MMT (Coil et al. 2008)
800ks data
The X-ray Universe 2008, Granada
AGN formation models
“QSO mode”
Merger (QSO-mode) models (e.g. Hopkins et al. 2005):
• gas rich major merger• gas inflows trigger BH
accretion & starbursts• dust/gas clouds obscure AGN
• AGN feedback sweeps away gas, quenching SF and BH accretion
“Radio mode”
Weak AGN feedback models in dense regions (e.g. Croton et al. 2006; Bower et al. 2006):
• cooling flows in groups or clusters large cold-gas reservoirs at galaxy centre
• weak AGN activity invoked to suppress cooling flows by either heating of mechanically sweeping away the gasHydra-A cluster,
McNamara et al. 2000
Kazantzidis et al. 2005
The X-ray Universe 2008, Granada
Colour-magnitude relationDEEP2 survey, 0.4<z<1.4; Willmer et al. 2006
• Colour bimodality:– Blue cloud: star-forming – Red sequence: evolved stellar
pop• Galaxy stellar mass builds via
mergers in blue cloud• Rapid quenching RS• Are AGN responsible for
quenching?• Or for maintaining galaxies on
RS?
Merger-driven star formation
Quenching
Dry mergers?
e.g. Strateva et al 2001; Bell et al 2004; Faber et al 2007
The X-ray Universe 2008, Granada
Colour-magnitude relation for AGN
z=0.6-1.4; Nandra et al. 2007
The X-ray Universe 2008, Granada
Colour-magnitude relation for AGN• Are AGN responsible for the
quenching?• Obscured X-ray sources in RED
cloud: old stellar populations• X-ray surveys select AGN after the
quenching of the star-formation• Are there obscured AGN (in star
forming galaxies) below X-ray detection threshold?
• Are obscured AGN found in post starburst galaxies?
z=0.7-1.4
z=0.2-0.7
Coil et al. 2008
The X-ray Universe 2008, Granada
X-ray stacking results: 24m bright sample
• Hard signal around valley and in red sequence, C>–0.15
• Obscured AGN associated with transition galaxies
• <Lx> = 1041 erg s-1
Stack X-ray emission of galaxies at different regions of CMD and in post starburst galaxies
Georgakakis et al. 2008
Stacked signal of 26 post starbursts: HR > 0.35. <LX>~1041 ergs/s
The X-ray Universe 2008, Granada
AGN host galaxy morphologies
Gini coefficient: clumpiness; M20: central concentration
Abraham et al. 2003; Lotz et al. 2004
Pierce et al. 2007
0.2<z<1.4
LX>1042 erg s-2
65% E/S0/Sa
Massive, bulge dominated, red, evolved hosts
The X-ray Universe 2008, Granada
AGN stellar mass function
Bundy et al. 2008
No Evidence for AGN hosts “downsizing” in mass
Accretion rate evolution?Also Babic et al. 2007 for z<1 in CFD-S
Hasinger et al. 2005
The X-ray Universe 2008, Granada
Large scale structure
AGN: Massive galaxies tracing large scale structure
A. Coil
Also ECDF-S: Silverman et al. 2008; XBootes Murray et al. 2005; Hickox et al. 2008
The X-ray Universe 2008, Granada
AGN/Galaxy cross-correlation functionSplit into 2 redshift bins: z=0.2-0.7 and z=0.7-1.4X-ray AGN cluster like red galaxies, at z~0.5 and z~0.9
Coil et al. 2008
Relative bias of X-ray AGN to galaxies:
z=0.7-1.4 red gals: 1.1 (0.1)
blue gals: 1.7 (0.1)
z=0.2-0.7 red gals: 1.1 (0.1)
blue gals: 1.4 (0.1)
Coil et al. 2006
The X-ray Universe 2008, Granada
AGN: relationship to groups
• Gerke et al. (2006) optical spectroscopic groups
• 42% of X-ray AGN in groups• Excess compared to general
population (~99%)• Tentative excess relative
to matched galaxy population (~91%)
• Tentative evidence that field AGN more luminous than group AGN (~98%)
Also Miyaji et al. 2007; Silverman et al. 2008
X-ray
Randomised optical
0.7< z< 1.4; Georgakakis et al. 2008
Randomised optical
X-ray
The X-ray Universe 2008, Granada
Conclusions
• Typical AGN at z~1 are in massive, red host galaxies– Star formation has terminated or is terminating– Many obscured AGN on red sequence– Bulge dominated, mergers not main trigger
• Stellar Mass Function– Flat, non-evolving, no downsizing in mass
• Large scale structure environment– Dense environments (cluster like hosts)– Around ~40% in groups
• Most black hole growth at z<1 not in “QSO mode”
The X-ray Universe 2008, Granada
AEGIS-X advertisement
• All reduced data and data products for AEGIS-X released 1 May 2008.
• Processed other Chandra deep fields in same way and reduced data, data products & source catalogues also released– Chandra Deep Field North (2Ms)– Chandra Deep Field South (2Ms)– Extended Chandra Deep Field South (4 x 250 ks)– Also large area, shallow ELAIS-N1 and XBootes
surveys
http://astro.imperial.ac.uk/research/aegis