aegis-x: results from the chandra survey of the extended groth strip

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)


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


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


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


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


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


Colour-magnitude relation for AGN

z=0.6-1.4; Nandra et al. 2007


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


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


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


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


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


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


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


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”


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

aegis-x: results from the chandra survey of the extended groth strip

Documents

obscured agn

agn hosts

xray agn cluster

agnare agn responsible

red galaxies

agn stellar mass functionbundy

obscured xray sources

massive galaxies