# Presentation: 420859

## AGN/GALAXY COEVOLUTION

- Kirpal Nandra
- Imperial College London

*With help from... Antonis Georgakakis, Elise Laird, *
*Kevin Bundy, Alison Coil, Darren Croton and the AEGIS team....*

- Point source contaminant

- WHIM Backlight

- Cooling problem get-out clause

- Scaling relation fudge factor

## AGN EVOLVE

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- Typical BH mass or accretion rate reduces with *z*?

**AGN EVOLVE**

- Hasinger et al. (2005)
- Also Ueda et al. 2003

- La Franca et al. 2005

## GALAXIES EVOLVE

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**GALAXIES EVOLVE**

- SFRD: Hopkins & Beacom (2006)

- AGN number density:
- Silverman et al. (2005)

- Similar evolution:
- Boyle & Terlevich 1998

## GALAXIES AND AGN CO-EVOLVE

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**GALAXIES AND AGN CO-EVOLVE**

- M-σ relation,

- Black hole mass correlated to host galaxy bulge mass.
-   	
- Formation of bulge and growth of black hole are related.
- 	
- AGN play a significant role in the evolution of galaxies

- Magorrian et al. 1988; Gebhardt et al. 2000;
- Ferrarese & Merrit 2000; Tremaine et al. 2002

## GALAXIES EVOLVE (2)

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**GALAXIES EVOLVE (2)**

- DEEP2 survey, 0.4<*z*<1.4; Willmer et al. 2006

- Colour bimodality:
- Blue cloud: active star-forming galaxies
- Red sequence: no SF, evolved stellar pop
- Galaxy stellar mass builds via mergers in blue cloud
- Rapid quenching to red sequence. Mechanism?
- Further red sequence growth via “dry mergers”?

**e.g. Strateva et al 2001; Bell et al 2004; Faber et al 2008**

**Merger-driven star formation**

**Quenching**

**Dry mergers?**

- KEY QUESTION: WHAT IS THE QUENCHING MECHANISM?

## QSO MODE FEEDBACK

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**QSO MODE FEEDBACK**

- Gas rich major merger
- Inflows trigger BH accretion & starbursts
- Dust/gas clouds obscure AGN
- AGN wind sweeps away gas, quenching SF and BH accretion. _x0001_

- Hopkins et al. 2006

- Hernquist (1989)
- Springel et al. (2005)
- Hopkins et al. (2006)

## K. Nandra: AGN/Galaxy Coevolution

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## FEEDBACK AND THE M- RELATION

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**FEEDBACK AND THE M-******** RELATION**

- Silk & Rees (1988)

- King 2003

- Tremaine et al. 2002

- Winds drive out gas from galaxy when:

## CO-EVAL STAR FORMATION/BH GROWTH?

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**CO-EVAL STAR FORMATION/BH GROWTH?**

- Submm emitting galaxies undergoing intense SF
- Many detected in X-rays
- >40% (100%?) of radio bright sources w/submm emission are AGN
- “Continuous” BH growth
- Hard X-ray spectra
***Co-eval obscured SF and accretion: ***_***QSO mode?***__ _

**Chapman et al. 2003; Alexander et al. 2005a,b**

## CO-EVAL STAR FORMATION/BH GROWTH?

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**CO-EVAL STAR FORMATION/BH GROWTH?**

- AGN

- Starforming

- Stacking

- Pure submm sample  of Pope et al. (2007)
- ~25% AGN, spectra not particularly hard

**Laird et al. (2008)**

- Alexander et al

**Our work**

## RADIO MODE FEEDBACK

- z>1: Quasar Epoch

**RADIO MODE FEEDBACK**

- Croton et al. 2006

## RADIO MODE FEEDBACK

**RADIO MODE FEEDBACK**

- z>1: Quasar Epoch

- z<1: Radio Mode

- Croton et al. 2006

## A complete picture of galaxy evolution probably needs both

**AGN FEEDBACK**

|  | When? | Trigger? | Feeding? | Consequence? |
| --- | --- | --- | --- | --- |
| Quasar
Mode | at early times  | gas rich mergers | cold gas | BH growth,
sets properties of ellipticals |
| Radio
Mode | at late times | BH & hot halo large enough? | hot gas?
stellar winds? | suppresses cooling gas, shuts down SF |

## THE AEGIS SURVEY

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**THE AEGIS SURVEY**

***AEGIS-X***
***Chandra***** AO-3:**
- 200ks over 0.08 deg2
**(Nandra et al. 2005)**
*Chandra* AO6:
**1.4 Ms over 0.5 deg****2**
*80 (70)% of soft (hard) XRB*
**(Laird et al. 2008)**
*Chandra *AO-9:
**1.8 Ms over 0.2 deg****2**
- DEEP 2/3 spectroscopy, FIDEL MIPS, HST, IRAC GTO, VLA, GALEX, CFHTLS blah blah blah

- aegis.ucolick.org; Davis et al. (2007)

## THE AEGIS-X SURVEY

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**THE AEGIS-X SURVEY**

- 1325 X-ray sources
- ~35% spectroscopic completeness
- (DEEP3  60%)
- Photometry, BRIK
- (CFHTLS/IRAC, good photoz)

- X-ray: Laird et al. 2008

- Spectroscopy:
-  Keck/DEEP2 (Davis et al. 2003)
-  MMT Coil et al. (2008)

- A. Georgakakis

- ---- L* at *z*=1

## RELEVANT OBSERVATIONS

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**RELEVANT OBSERVATIONS**

- AGN host galaxy colours and star formation
- Morphologies
- Stellar Mass Function
- Large scale structure environment
- Relationship to groups

## THE AGN COLOR-MAGNITUDE RELATION

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- Nandra et al. 2007

**THE AGN COLOR-MAGNITUDE RELATION**

## THE AGN COLOR-MAGNITUDE RELATION

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- Coil et al. 2008

**THE AGN COLOR-MAGNITUDE RELATION**

- z=0.7-1.4

- z=0.2-0.7

## X-RAY STACKING VERSUS COLOUR

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**X-RAY STACKING VERSUS COLOUR**

- 24**m bright, 0.4<*z*<0.9

- Hard signal around valley and in red cloud, *C*>–0.15
- Obscured AGN associated with transition galaxies

- Georgakakis et al. (2008)

**Notes:**
First of all the stacking results for 24-micron bright galaxies. On the left is the CMD of this population and on the right I plot hardness ratio as a function of position on the CMD. The HR measures how hard is the mean X-ray spectrum of different galaxy samples. Positive values correspond to hard spectra, typical of obscured AGN and negative values to softer mean X-ray spectra, such as those of unobscured AGN or star-forming galaxies. So the the vertical lines correspond to power-law X-ray spectral energy distributions. The typical spectrum of an unobscured AGN corresponds to Gamma=1.9, Gamma=1.4 corresponds to the spectrum of the diffuse XRB and Gamma=1.0 implies obscured AGN activity. 

The horizontal axis, DeltaC, measures the distance of different CMD bins from the line separating the blue and the red cloud. So the valley between the two clouds corresponds to DeltaC=0 and is colour coded with green. Positive values of DeltaC corresponds to red cloud galaxies and negtivae values to the blue cloud. 

The points correspond to the stacked signal of different colour bins and the horizontal error bars correspond to the width of each bin. An arrow pointing downward means an upper limit in the hardness ratio. So what we find is that the mean X-ray hardness ratio is a function of position on the CMD. The signal is relatively soft for blue cloud galaxies, consistent with SF or unobscured AGN. At the top of the blue cloud and the valley the signal is becoming harder and this hardening persist in the red cloud.  

## AGN HOST MORPHOLOGIES

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**AGN HOST MORPHOLOGIES**

- CDFs+AEGIS 0.7<*z*<1.3
- Bulges dominate (merger remnants?)
- Spirals 2nd larger group
- Ongoing interactions minority

**Notes:**
The optical morphologies also support this, shown that most AGN are associated with bulge-dominated early type galaxies, the 2nd larger groups among AGN are spirals while ongoing interacting systems are a minority. 

## HOST GALAXY MORPHOLOGIES

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**HOST GALAXY MORPHOLOGIES**

- Gini coefficient: clumpiness; *M**20*: central concentration
- Abraham et al. 2003; Lotz et al. 2004

- Pierce  et al. 2007

- MASSIVE, BULGE DOMINATED, RED, EVOLVED HOSTS

## AGN STELLAR MASS FUNCTION

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**AGN STELLAR MASS FUNCTION**

- Bundy et al. 2008

- No Evidence for AGN  Hosts
- “Downsizing” in mass

******Accretion rate evolution?**

- Also Babic et al. 2007

**Notes:**
AGN hosts are typically massive galaxies. However, the mass function of these systems, shown here with the green shaded regions, does not follow the Schecter formula of the galaxy mass function. In contrast it is nearly flat. Also there is little evidence for evolution, I.e shift toward more less massive galaxies with decreasing redshift, although more data are needed to further explore this. 

## LARGE SCALE STRUCTURE ENVIRONMENT

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**LARGE SCALE STRUCTURE ENVIRONMENT**

- Black: DEEP2
- Red: X-ray AGN

- 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

- WARNING TO WHIM HUNTERS!

## LARGE SCALE STRUCTURE ENVIRONMENT

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**LARGE SCALE STRUCTURE ENVIRONMENT**

- vs. host luminosity

- vs. host colour

**Comparing with galaxies samples same range of LSS**

**Georgakakis et al. (2007)**

## AGN/GALAXY CROSS-CORRELATION

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**AGN/GALAXY CROSS-CORRELATION**

**Split into 2 redshift bins:  z=0.2-0.7 and z=0.7-1.4**
**X-ray AGN cluster like red galaxies, not blue, 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

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**AGN: RELATIONSHIP TO GROUPS**

- Gerke et al. (2006) optical spectroscopic groups
**40% of X-ray AGN in groups**
- Excess compared to general population (~99%)
- Tentative excess relative to matched galaxy population (~90%)

- See also: Miyaji et al. 2007; Silverman et al. 2008

**Notes:**
AGN at z~1 are typically found in high density environments, and recent studies underline the significance of the group environment in the evolution of these systems

## NON-DETECTION OF DEEP2 GROUPS

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**NON-DETECTION OF DEEP2 GROUPS**

**Fang et al. (2007)**

- Spectroscopically selected groups at z>0.7 (Gerke et al. 2006)

- DEEP2 groups

- Optical clusters

- X-ray clusters

## CONCLUSIONS

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**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, ~0 mergers
- Stellar Mass Function
- Flat, non-evolving, no downsizing in mass
- Large scale structure environment
- Dense environments (cluster like hosts)
- Around ~50% in groups
***Most BH growth not in “QSO mode”***
- No high z group extended X-rays (yet)
- More to come!

## Morphology of AGN hosts at z~1

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**Morphology of AGN hosts at z~1**

- CDFs+AEGIS 0.7<*z*<1.3
- Bulges dominate (merger remnants?)
- Spirals 2nd larger group
- Ongoing interactions minority

**Notes:**
The optical morphologies also support this, shown that most AGN are associated with bulge-dominated early type galaxies, the 2nd larger groups among AGN are spirals while ongoing interacting systems are a minority. 

## AGN host galaxy morphology: mergers or merger remnants?

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**AGN host galaxy morphology: ****mergers or merger remnants?**

- AEGIS and CDF-North
- Morphological classification (HST):
- mergers (ellipticals, interacting, QSOs)
- Disks (spirals)
- 	Only 50% of AGN in major-mergers

- 

**Notes:**
Let me move on to the morphological classification for the entire AGN population. The question here is how many of the X-ray selected AGN at z~1 can be of merger origin.  The answer that only about 50%. The remaining half are associated with galaxies that are not the product of major mergers. The evidence is shown here, we have used HST data in the AEGIS and the CDF-N surveys to classify AGN into two groups, merger candidates and disks. The first category includes elliptical galaxies, systems with disturbed morphology suggesting ongoing interactions as well as QSOs. The disk category includes only isolated spirals. Major mergers are catastrophic events that destroy disks. So if there is evidence for disk the galaxy cannot be the product of major merger. We find that at least 45% of the AGN in these surveys are are in the disk category and therefore not of merger origin. 

## X-ray source optical morphology

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**X-ray source optical morphology**

- X-ray AGN: bulge dominated

- 	Gini–*M**20* diagram (Lotz et al. 2004):
- Gini: distribution of galaxy’s flux
*M**20*: 2nd moment of the brightest 20% of the galaxy’s flux

- Pierce et al. 2007

## COLOUR-DEPENDENCE

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- AGN on red sequence are more clustered than in blue cloud

**Coil et al. in prep**

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## AGN in post-starbursts at z~1

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**AGN in post-starbursts at z~1**

- 	44 AEGIS galaxies with post-starburst spectra (0.7<z<0.9)
- stacking: hard mean X-ray spectrum
- X-ray detections: high fraction of X-ray sources in post-starbursts (98% significance)

## CDF-South:
X-ray: AGN 
Ultra-deep radio (1.4GHz): dominated by starbursts

mid-IR: Radio emission of some AGN associated with  star-formation 

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- CDF-South:
- X-ray: AGN
- Ultra-deep radio (1.4GHz): dominated by starbursts
- mid-IR: Radio emission of some AGN associated with  star-formation

- Rovilos et al. 2007

**Stellar population of AGN hosts at z~1: evidence for starbursts?**

**Notes:**
The mid -IR properties of this population are also consistent with star-formation. This is demonstrated in shown in the Figure on the right which plot mid-IR 24 micron luminosity as a function of radio luminosity on the horizontal axis. For star-forming galaxies these two quantities are tightly correlated and this correlation is shown with the diagonal lines in this plot. The red dots are X-ray selected AGN with radio counterparts and you can see that many of them are consistent with the relation for star-formation, further suggesting that their radio emission is dominated by star-formation. 

## Environment of AGN at z~1: field or groups?

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**Environment of AGN at z~1: ****field or groups?**

- 	AEGIS group catalogue (Gerke et al. 2005)
- 	40% of AGN in groups

- Georgakakis et al. in prep

- 

**Notes:**
Finally, the environment of AGN. Using data from the AEGIS we have shown that a large fraction of the AGN, about 40%, are in groups. 

## DEEP VS WIDE

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- Bright sources only (~Bootes limit)

**DEEP VS WIDE**

- Nandra et al. sample (200ks)

## OPTICAL IDENTIFICATION

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**OPTICAL IDENTIFICATION**

- Chance projections in AEIGS to I=25:
- 7% IDs at 1.5”; **20% at 3”**; 30% at 5”
- REAL IDs are optically fainter ****** **high z?

- ID of SCUBA source GN11 (w/Alex Pope + Douglas Scott UBC)

- HST/ACS

- IRAC 3.6mm

- radio

- MIPS 24mm

**Alexander et al X-ray c/part**

**Pope et al. c/part**

****** ****MAJOR IMPACT ON NUMBER OF HIGH Z AGN/REIONIZATON**

****** ****SCUBA AGN fraction may be lower than Alexander et al. (2005)**

## X-RAY INCOMPLETENESS

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**X-RAY INCOMPLETENESS**

- X-ray images are
- Highly inhomogeneous
- In poisson regime
- Source detection “black box” (e.g. wavdetect)
- Detection inconsistent with sensitivity
- Eddington bias, poisson noise, incompleteness
- Embodied in sensitivity curve

- Georgakakis et al., in prep

## DO X-RAY SURVEYS FIND ALL AGN?

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**DO X-RAY SURVEYS FIND ALL AGN?**

- Heckman et al. (2005) say OIII better at selecting local AGN than X-ray
- Steidel et al. (2002) found 70% of X-ray AGN at z=3 LBGs from spectroscopy
- Also one AGN X-ray undetected in 1 Ms
- Sarajedini et al. (2006): 70% of optically variable nuclei X-ray undetected (200ks Chandra)
- AEGIS (Renbin Yan, Berkeley):
- 60% of X-ray sources have AGN line ratios
- 10% have no OIII
**Only 30% of line-ratio selected (candidate) AGN are X-ray sources!**

- Not to mention Spitzer selection...  need multi- approach
- But remember flux limits...

## OTHER ISSUES

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**OTHER ISSUES**

- Separating AGN and starbursts
- Is it reasonable to assume Compton thick evolve like unobscured
- Is alpha_ox dependent on UV luminosity really?
- How does variability affect SEDs. Dispersion?
- Effects of variability effects on photoz?

## CLUSTERING vs. HOST LUMINOSITY

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