anton koekemoer (stsci) black holes - stsci spring symposium, 23-26 apr 2007 1 agn and star...

Anton Koekemoer

(STScI)

Black Holes - STScI Spring Symposium, 23-26 Apr

2007

1

AGN and Star Formation at High Redshift

Anton Koekemoer (Space Telescope Science Institute)

+ CDFS/GOODS-AGN (Alexander, Brandt, Bergeron,

Conselice, Chary, Cristiani, Dickinson, Elbaz, Grogin, Mainieri, Schreier, Treister, Urry, Wiklind...)

+COSMOS-AGN (Brusa, Carilli, Capak, Civano, Comastri, Daddi, Elvis, Fiore, Hasinger, Ilbert, Impey, Jahnke, Mainieri, Martinez-Sansigre, Mobasher, Murayama, Nagao, Oyama, Salvato, Sanders, Sasaki, Schinnerer, Scoville, Smolcic, Treister, Taniguchi, Trump, Urry, Zamorani)

Anton Koekemoer

(STScI)


2007

2

Black holes in context:• Likely tracer of hierarchical dark matter halos• Provide hard ionizing continuum, relevant to low- reionization

• May regulate galaxy growth / SFR via feedback• M- relation suggests intimate connection between BH/galaxy formation and growth

To date:• At z ~ 6 - 6.5, already havesupermassive BHs to ~ 109 Mo

(Fan et al 2001-06; Willott et al. 2003;Vestergaard et al. 2004)

• AGN LF evolves stronglyfrom z~6 to z~2; PLE isruled out (Fan et al. 2001+;Richards et al. 2006)

• Faint end of AGN LF steepensat z~6 (Jiang et al 2009, Fan et al.

(Richards et al. 2006)

Anton Koekemoer

(STScI)


2007

3

• Instead of PLE, AGN appear to follow “anti-hierarchical evol” -- luminosity-dependent density evolution “LDDE” at least for XLF (Ueda et al. 2003, Hasinger et al. 2005; Gilli, Comastri, Hasinger 2006), QSO LF (Richards et al. 2006); also Merloni et al. (2004):– luminous AGN peak earlier (z~2-3)– fainter AGN peak more recently (z~1)

(XLF; Hasinger et al. 2005)

(QSO LF, Richards et al. 2006)

Anton Koekemoer

(STScI)


2007

4

• Below LX ~ 1044 erg s-1, density evolution is drastically different from higher-lum sources, peaking at lower z

• higher-lum sources show essentially pure density evolution

• suggests possible difference in accretion / galaxy evolution as a function of luminosity

(Hasinger et al. 2005)

-15

-13

-11

-9

-7

-5

-3

41.5 42.5 43.5 44.5 45.5 46.5 47.5

Log Lx (erg/s)

z = 0.015 - 0.2

z = 0.2 - 0.4

z = 0.4 - 0.8

z = 0.8 - 1.6

z = 1.6 - 3.2

z = 3.2 - 4.8 -15

-13

-11

-9

-7

-5

-3

0.1 0.6 2.4

redshift

d(phi)/d(logL) (Mpc-3)

Lx = 42.0

Lx = 43.0

Lx = 44.0

Lx = 45.0

Lx = 46.0

Lx = 47.0

Lx = 48.0

Anton Koekemoer

(STScI)


2007

5

QuickTime™ and a decompressorare needed to see this picture.

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are needed to see this picture.

Anton Koekemoer

(STScI)


2007

6

Questions:• How do the most massive BHs form within < 1 Gyr?• How does BH growth influence the M- relation?• What is the ionizing budget of AGN integrated over the LFbeyond z ~ 6, and its contribution to reionization?

• (How) does obscured/unobsc. AGN ratio evolve at high z?

Our knowledge has been limited by the following:• only the top of the AGN LF has been studied at z ~ 6• no AGN previously confirmed at z > 7

Approach:• Understand AGN / SFR evolution at z ~ 2 - 5• Set out to quantify the faint end of AGN LF at z ~ 6• Search for more luminous AGN at z > ~ 6 - 7

Anton Koekemoer

(STScI)


2007

7

FOpt (mag)

log FX (erg s-

1cm-2)

AGN

Require Wide+Deep X-ray / Optical / IR Surveys:• Depth probes faint/moderate-lum AGN to high z• Area probes high-lum AGN at high z• (Hard) X-rays penetrate obscuring torus, IR probes rest-frame optical emission from AGN + host galaxy

New part of parameter space:• Combined optical + X-ray depth allows wider exploration of FX/FOpt:

Anton Koekemoer

(STScI)


2007

8

Some current relevant surveys

Area

Fx (cgs) R(AB) I(AB

)z(AB)

J(AB)

K(AB)

f(3.6)

X-Bootes 9.3 4.0e-15 25.5 24.9 - 21.0 20.6 5.0

COSMOS 2 7.0e-16 26.8 26.2 25.2 - 21.6 0.9

HELLAS2XMM 0.9 7.5e-15 25.0 - - - 19.1 15.0

XMM/SWIRE/ELAIS-S1 0.6 1.0e-

13 24.5 24.5 - 21.0 20.0 3.7

SXDF/UKIDSS-UDS 0.5 1.3e-15 27.2 - 24.0 22.6 22.5 3.7

ECDFS/MUSYC 0.25

3.9e-16 25.8 24.7 23.6 23.5 23.0 0.8

AEGIS 0.2 8.2e-16 26.5 26.0 25.0 24.0 22.6 1.0

GOODS 0.2 2.4e-17 26.2 27.1 26.6 25.5 25.1 0.17

Anton Koekemoer

(STScI)


2007

9

X-ray vs R-band

1

10

100

0.1 1 10Area/flim(X)

Area/flim(R)

X-ray vs z-band

0.1

1

10


Area/flim(I)

X-ray vs K-band

0.01

0.1

1


Area/flim(K)

X-ray vs IRAC3.6

0.1

1

10


Area/flim(3.6)

GOODS

GOODS

GOODS

GOODS COSMOS

COSMOS

COSMOS

COSMOS

ECDFS

ECDFS

ECDFS

ECDFS

SXDF

SXDF

SXDF

SXDF

AEGIS

AEGIS

AEGIS

AEGIS

Anton Koekemoer

(STScI)


2007

10

A Brief Selection of Extragalactic Survey Fields• UDF:

– 3’x3’ HST/ACS (B,V,i,z) + NICMOS (JH)– Other coverage same as CDFS

• GOODS/CDFS+CDFN:– 2x 10’x16’ HST/ACS (B,V,i,z)– Chandra 1Ms, Spitzer (3-70 m), ATCA, VLA, VLT, KPNO

• GEMS/ECDFS:– 30’x30’ HST/ACS (i,z)– Chandra 1Ms+4x 250ks, Spitzer, ATCA, CTIO

• EGS:– 10’ x 1o HST/ACS (i,z)– Chandra 7x50ks, CFHT (UBVRIz)

• COSMOS:– 1.4o x 1.4o HST/ACS (z) + NICMOS (J,H)– Subaru (UBVRiz), XMM, Spitzer, VLA

Anton Koekemoer

(STScI)


2007

11

CDFS/GOODS-S+N survey:• powerful combination of wide area and depth, opt/Xray: CDFS + CDFN have 1 & 2 Msec Chandra depth respectively– X-ray depth sufficient for AGN LF faint end (LX~1043-44 erg s-1) up to z ≥ 6 - 7

– area sufficient (0.1 sq deg) to provide number statistics on AGN LF at these redshifts

• More than 800 AGN from Chandra in GOODS-N & S (> 600 covered by HST/ACS and Spitzer)

• Extensive optical spectroscopic coverage• Deep multi-band optical/NIR/Spitzer coverage:

– JHK + Spitzer/IRAC 3.6 – 8 m observations trace host stellar mass for z > 1-2

– Spitzer/MIPS 24 m data helps constrain thermal dust emission

Anton Koekemoer

(STScI)


2007

12

GOODS = Great Observatories Origins Deep Survey (Hubble, Chandra, Spitzer)• Centered on CDFS, CDFN

Supporting observations:• VLT, Gemini, Keck, Subaru, KPNO, CTIO, VLA, ATCA, JCMT

Goals:• Extensive, deepmulti- coverage

• Large enougharea to probeboth galaxy andAGN evolution

• Two fields reduceimpact of cosmicvariance

Anton Koekemoer

(STScI)


2007

13

Advantages of X-ray selection:• avoid obscuration effects in optical/IR• at z > 2-3, hard X-rays are redshifted into soft observed X-ray bandpass, allows a more complete selection of obscured AGN (except for Compton thick sources)

• allows selection of more AGN than radio selection.

Other wavelengths needed:• deep optical to ensure good identification of dropouts:– at least R,I, preferably also z

• deep near-IR to provide detections relative to optical:– at least K, preferably also J,H

• Spitzer data to allow SED fitting:– at least IRAC 3.6 - 8 micron, preferably also MIPS 24 micron

Anton Koekemoer

(STScI)


2007

14

Starformation in obscured AGN: IRAC colours• Significant fraction (~50%) of z~2-4 obscured AGN show strong SFR signatures (Brusa et al. 2009):– S(8.0)/S(4.5) < 2 classified as SFR-dominated (Pope et al. 2008)



(Brusa et al. 2009)

Green points: 24m selected field galaxies

Blue points: AGN LX < 1043 erg s-1

Red points: AGN LX > 1043 erg s-1

Purple, yellow: other samples of high-z obscured AGN (Pozzi et al 2008, Pope et al 2008)

Anton Koekemoer

(STScI)


2007

15

Starformation in obscured AGN: SFR• Comparison with field galaxies:

– For 65% of the obscured AGN, find significant SFR (>10M/yr)

– Result is robust for both optically and MIR-selected samples

(Brusa et al. 2009)

Upper panel: optically-selected field galaxies, AGN

Lower panel: MIPS 24m-selected field galaxies, AGN



(Brusa et al. 2009)

Anton Koekemoer

(STScI)


2007

16

Starformation in obscured AGN: SSFR• Significant fraction of AGN still have active SSFR w.r.t mass (Alonso-Herrero et al. 2008, Busa et al. 2009)

• Red colours likely due to dust (not stellar population age)



Anton Koekemoer

(STScI)


2007

17

Increased warm dust in z~1-2 obscured AGN:• Lanzuisi et al (2009) sample: SWIRE sources, F24/Fopt > 1000

• X-ray spectral properties used to compare with AGN in the local universe (yellow shaded region)

• Result: majority of the AGN have significant MIR excess wrt intrinsic Lx: requires excess dust component relative to local



Anton Koekemoer

(STScI)


2007

18

Compton-Thick AGN Redshift Evolution

Red: Lx > 1043 erg/s

Blue: Lx > 1044 erg/s

LFs:

Della Ceca et al (2009)

Yencho et al (2009)

Normalized to Treister et

al

Steep rise above z~2 relative to non-CT AGN



Treister et al.

(2009)

Anton Koekemoer

(STScI)


2007

19

Expected contributions of AGN & starbursts to LIR• Examine triggering of AGN and starbursts in mergers (Hopkins et al 2009) - how significant is the contribution from AGN to the MIR LF?

• Find that, for log(LIR)>12-13, both starburst & AGN dominate LF To a similar extent, up to z~3



Anton Koekemoer

(STScI)


2007

20

HST Morphologies of MIR Excess AGN





Anton Koekemoer

(STScI)


2007

21

High-z AGN Candidates: “EXOs”• Based on SED change with z:

– Drop-outs in z850lp (>27)

– Anomalous Fx/Fopt (>100)– Red z850lp - K (>4)

• Expect mostly obscuredsources, but unobscuredAGN are not excluded

Highest FX/FOpt:• found in several studies so far (Koekemoer et al 2002,2004; Brusa et al. 2004; Treister et al 2006; Koekemoer et al 2009)

• EXO’s - Extreme X-ray / Optical sources– Only revealed by extending optical depth below ~27– Optically faint sources with anomalously high FX/FOpt >100

– Typically have extremely red z-K > 4-6– Appear to have no comparable analogs in the local universe

CDFS (Brandt et al, Koekemoer et al, Treister et al)

FX/Fopt

= 0.1

FX/Fopt

= 10

Anton Koekemoer

(STScI)


2007

22

Candidate high-z AGN: X-z-K selection: X-ray properties:• Well-detected by Chandra(~10-16-10-15 erg s-1cm-2)

• FX/FOpt is a lower limit,and is > ~100x abovethe average for AGN

• Generally have soft andhard X-ray emission (excludes z<2 obscured AGN)

Redder z-K colour:• most AGN with FX/FOpt ~ 0.1 - 10 have fairly tight z-K ~1-2, with some slight scatter:– z-K ~ -1 to 2 for quasars/Seyferts– z-K ~ 2 to 4 for ERO’s

• However, the EXO high-z candidates generally have z-K >4

Anton Koekemoer

(STScI)


2007

23

CDFS EXOs

Anton Koekemoer

(STScI)


2007

24

EXO/high-z candidates from GOODS N+S HST/ACS VLT+NOAO SPITZER/IRAC MIPS

Anton Koekemoer

(STScI)


2007

25

EXO Close-up (contours = Chandra 0.5-8 keV)

Anton Koekemoer

(STScI)


2007

26

SED Fitting Overall parameterization:• Use CB03, Maraston06, vary IMF, metallicity

• - stellar mass formed as SSP / CSP• - reddening (Fall & Charlot; Calzetti; SMC; LMC)

Fits driven by two observational features:• red opt/NIR - IRAC• colours within IRAC

General results:• Use the fits to identify plausible z~2-3 interlopers• Down-select to the remainder that are not well fit by z~2-3:– Follow these up with NIR spectroscopy (Subaru/Gemini/VLT)

– Use their number counts to directly constrain high-z logN-logS

Anton Koekemoer

(STScI)


2007

27

• total ~2 million galaxies, ~1300 AGN (XMM: Hasinger et al, Brusa et al 2007) + radio (Schinnerer et al 2007)

~1.4°

Anton Koekemoer

(STScI)


2007

28

COSMOS X-Ray Observations (Comastri, Brusa 2007):• XMM dataset: 53 pointings, ~1.6 sq deg (Brusa et al)

• Chandra dataset (1.8 Msec) ~1.4 sq deg, deeper than XMM

• Total of ~1300 sources in XMM, ~1800 in Chandra• Limiting fluxes:

– F(0.5-2 keV) ~ 1 x 10-15 erg cm-2 s-1

– F(2-10 keV) ~ 5 x 10-15 erg cm-2 s-1

Full survey:• Combined XMM + Chandra ~2500 sources to date• identify with ACS sources• remove ambiguous IDs

Finally, produce sample of EXOs:• detect a total of 35 EXOs (cf ~7 for GOODS/CDFS)• Likely a mixture of z~2-4 sources and z>~6 candidates, similar to GOODS

Anton Koekemoer

(STScI)


2007

29

ACS-i K SPITZER/IRAC1,2,3,4

EXO/high-z candidates from COSMOS

Anton Koekemoer

(STScI)


2007

30

ACS-i K SPITZER/IRAC1,2,3,4

(cont’d)

Anton Koekemoer

(STScI)


2007

31

Constraining high-z AGN LF:• Use hard X-ray XLF to estimate expected number of optically unidentified sources as a function of redshift:– Most of the optically unidentified AGN are evolved interlopers at intermediate z > 2

• Compare with observed number of undetected sources:– use existing X-ray detection limits– apply optical detection cut-off (z(AB) ~ 27.5 for ACS)

• Integrate over X-rayluminosities at eachredshift bin:– Use the difference tocalculate cumulativenumber N(>6)

– Compare with N(>6)from XLF

Anton Koekemoer

(STScI)


2007

32

• Number of optically unID’d sources N(z) based onz(AB)=27.5 limit, for current Chandra catalogs, using:– X-ray sensitivity– Optical flux limits– Spitzer flux limits

• LDDE predicts total of ~5 AGN at z>7 in GOODS+COSMOS (out of all the X-ray sources with ACS coverage):

• After removing low-z interlopers, currently have 4 likely z~7 candidates in GOODS+COSMOS - rough agreement with LDDE

1.0

10.0

100.0

1000.0

-16.0 -15.0 -14.0 -13.0

Log F(0.5-8keV) (erg s-1

cm-2

)

N > F(0.5-8keV)

1.0

10.0

100.0

1000.0

-16.0 -15.0 -14.0 -13.0


cm-2

)

N > F(0.5-8keV)

z~0.3

1.0

10.0

100.0

1000.0

-16.0 -15.0 -14.0 -13.0


cm-2

)

N > F(0.5-8keV)

z~0.3

z~0.6

1.0

10.0

100.0

1000.0

-16.0 -15.0 -14.0 -13.0


cm-2

)

N > F(0.5-8keV)

z~0.3

z~1.2

z~0.6

c

1.0

10.0

100.0

1000.0

-16.0 -15.0 -14.0 -13.0


cm-2

)

N > F(0.5-8keV)

z~0.3

z~1.2z~2.5

z~0.6

1.0

10.0

100.0

1000.0

-16.0 -15.0 -14.0 -13.0


cm-2

)

N > F(0.5-8keV)

z~0.3

z~5

z~1.2z~2.5

z~0.6

1.0

10.0

100.0

1000.0

-16.0 -15.0 -14.0 -13.0


cm-2

)

N > F(0.5-8keV)

z~0.3

z~6

z~5

z~1.2z~2.5

z~0.6

1.0

10.0

100.0

1000.0

-16.0 -15.0 -14.0 -13.0


cm-2

)

N > F(0.5-8keV)

z~0.3z~8

z~6

z~5

z~1.2z~2.5

z~0.6

Anton Koekemoer

(STScI)


2007

33

New results - MOIRCS Spectroscopy (special thanks to Yoichi Oyama!)• NIR spectroscopy of remaining high-z candidates• Subaru - MOIRCS: ~4 hours/mask; objects faint (K~23+)

• Data reduction currently in progress• One example EXO spectrum (no lines detected so far..):



Anton Koekemoer

(STScI)


2007

34

Summary:• New results by several groups on z~2-4 AGN:

– Many AGN are now found to have strong MIR SFR signatures

– May be seeing “pre/post-blowout” QSO phase in action

• Overall number of high-z candidate AGN found in GOODS+COSMOS supports steepening of LF at z~6-7:– Intermediate-z interlopers successfully accounted for, and removed from dropout samples

– Not clear yet whether faint-end slope needs to change as well or whether evolution can be accounted for by change in L*

• Next steps:– larger/deeper coverage at MIR with Spitzer and Herschel to better constrain rest-frame opt/IR and dust SEDs

• MAIN QUESTION:– What observational signatures to look for in determining the direction of causality for BH / bulge growth?

anton koekemoer (stsci) black holes - stsci spring symposium, 23-26 apr 2007 1 agn and star...

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