The Links Between AGN and Galaxy Formation
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Transcript of The Links Between AGN and Galaxy Formation
Omar AlmainiUniversity of Nottingham
The Links Between AGN and Galaxy Formation
The Links Between AGN and Galaxy Formation
Galaxy formation models …and their problems The AGN/galaxy connection Feedback and AGN winds Observing black hole/bulge growth Summary & future prospects
CDM cosmological model in excellent agreement with wide range of observations:
e.g. CMB, galaxy clustering, type 1a SN, element abundances, Cepheid distance scale, stellar ages, baryon fraction in clusters…
Merger Tree for the Growth of a Dark-matter Halo
Semi-analytic Galaxy Formation Models
+Messy physics
(gas cooling, star-formation, dust, SN feedback etc…)
N-body merger trees
=
Hierarchical Galaxy Formation
Benson (2003)
Producing the local K-band luminosity function -SN feedback is essential!
Benson (2003)
Problem can be solved with extreme super-winds >5x1049 erg per solar mass required
Kauffmann et al. 2003; Balogh et al. 2004
Local galaxies are strongly bimodal
e.g. Daddi et al. 2002; Roche, Almaini et al. (2002), Roche, Dunlop & Almaini (2003); Somerville et al. (2003)
Data Model
Can’t make enough red galaxies at z>1
The diversity of ERO galaxies
30-40% old, passive systems30-40% old, passive systems 30-40% dusty starburst30-40% dusty starburst Typical redshifts 1.0<z<1.5Typical redshifts 1.0<z<1.5 Strongly clustered Strongly clustered High space densityHigh space density
Many old, massive systems Many old, massive systems
already in place at z~1-1.5already in place at z~1-1.5
Recent discovery of many old, passive systems at z>1.5
Using J-K>2 colour selection find population of very red galaxies at z>2
Van Dokkum et al. 2003
‘EROs’ at higher redshift
Cimatti et al. 2004
Glazebrook et al. 2004
Summary of galaxy formation problems
I. Predicts too many dwarf galsII. Predicts “cuspy” coresIII. Why are there no galaxies with > 300 km/s?
Classic Problems
I. Fail to produce EROsII. Fails to predict SCUBA sourcesIII. Bimodal local galaxy pop.
Newer Problems
Need a mechanism for switching off star-formation in most massive galaxies
II. The AGN/galaxy connection
All massive galaxies contain a SMBH
The black-hole/bulge mass relationship.
Gebhardt et al. (2000), Ferrarese & Merritt (2000)c.f. Magorrian (1998)
MBH = 0.2 % Mbulge
MBH = 1.5x108 2004
M
Can the black hole influence its host galaxy?
MBH = 2x10-3 Mbulge
AGN radiative energy EAGN ~ 0.1 MBH c2 = 2 x 10-4 Mbulge c2
Binding energy of the bulge Ebulge ~ Mbulge 2 ~ 10-6 Mbulge 2
300 c2
Less than 1% of the AGN energy could blow the galaxy apart
The X-ray background: Most accretion activity is absorbed
Unobscured AGN
“AGN winds are ubiquitous” - Brad Peterson
“My wind model explains everything” - Martin Elvis
APM-08279 – lensed BAL quasar at z=3.91
Fe XXV K ? v1~0.2 cv2~0.4c
Chartas et al. (2002)
Massive X-ray outflow in PDS 456
Reeves et al. (2003)
XMM EPIC pn/MOS
Massive X-ray outflow in PDS 456
Reeves et al. (2003)
XMM RGS-2
V~50,000 kms-1 NH = 5x1023
~ 10 M yr-1
Momentum outflow:
Mwind v ~ L Edd/c.
King & Pounds 2003
Investigated supercritical accretion
M > M Edd
.
~
Assuming all excess matter ejected in a wind:
1. Compton-thick, quasi-spherical outflow
2. Momentum outflow: Mwind v ~ f L Edd/c.
.
King 2003(c.f. Silk & Rees 1998, Fabian 1999,
Blandford 1999, Di Matteo et al. 2004… )
Mwind v ~ L Edd/c.
Momentum outflow:
Outflow drives wind bubble through host galaxy
Shell velocity v2 Ledd / 2
M(R) 2 R
MBH 4
Mgas(R) 2 R
The black-hole/bulge mass relationship.
Gebhardt et al. (2000), Ferrarese & Merritt (2000)c.f. Magorrian (1998)
MBH = 0.2 % Mbulge
MBH = 1.5x108 2004
M
Observations of AGN-drivensuper- winds now required!
A cartoon model of massivegalaxy formation
SCUBA phase quasar elliptical?
II. AGN in galaxy clusters
The Entropy Problem(SN not enough?)
XMM RGS (Virgo)Sakelliou et al. 2002
The Cooling-Flow Problem
Chandra
VLA
II. Observing joint black-hole/galaxy formation
100100
Wavelength / m
f
101010001000
What is so special about submm sources?
The James Clerk Maxwell Telescope
(Hawaii)
• Highly luminous (ULIRG) systemsHighly luminous (ULIRG) systems• SFR ~ 1000 MSFR ~ 1000 M yr yr-1 -1
• Massive systemsMassive systems• Evidence for outflowing windsEvidence for outflowing winds
Progenitors of massive
elliptical galaxies?
Results of submm surveys
Mass determinations for submm sources
Genzel et al. (2003)
Massive (CO) Massive (H)
Swinbank et al. (2004)
Semi-analytic models have great difficultyproducing submm sources…
Baugh et al. (2005)
Most SCUBA sources DO NOT contain powerful quasars
Almaini et al. 2003
5 "
5 "
William Herschel Telescope 4m Depth R~27 Seeing 0.7”
HST ACS Imaging – (Almaini et al. 2005)
5 "
“True” color image0.5-2.0 keV 2.0-4.0 keV 4.0-8.0 keV
1.945 MsACIS-I
exposure
P.I.: W.N. Brandt
“True” color image0.5-2.0 keV 2.0-4.0 keV 4.0-8.0 keV
1.945 MsACIS-I
exposure
P.I.: W.N. Brandt
17/20 SCUBA galaxies
X-ray detected
Alexander et al. 2005
Joint spectral fitting
12Ms Chandra spectra!
Composite 2-20 keV spectra (12Ms)
Relatively low Lx/LFIR ratios
“True” color image0.5-2.0 keV 2.0-4.0 keV 4.0-8.0 keV
1.945 MsACIS-I
exposure
P.I.: W.N. Brandt
Alexander et al. 2005
Modest X-ray luminosities
Lx = 1043-1044 ergs-1
Suggest black holes <108MM
Evidence for growing black holes?
Archibald et al. (2002)
Fuel supply
Eddington limited growth
Where do we go from here?Where do we go from here?
Need detailed prescription for AGN feedback in semi-analytic models. Can we detect merging black holes with LISA (Madau 2004)? How prevalent are AGN-driven winds? How massive were first black holes? What influence did they have on the IGM at z>10?
Conclusions Overwhelming evidence for CDM hierarchical structure formation
Problems with semi-analytical galaxy formation models - mechanism required to terminate SF in massive gals - plus other problems…
AGN feedback is a likely solution - may be related to the origin of the M/ relation - could also explain high-mass cut-off & cluster heating problem