1. Spheroid and Black Hole formation at high z
James Dunlop
Overview pulling together many different areas of work
Major and minor contributions from:
PhD students PDRAs/Afs Institute Staff
Geoff Taylor Marek Kukula John Peacock
Ian Waddington Dave Hughes Andy Lawrence
Elese Archibald Raul Jimenez Alan Heavens
Ross McLure Rob Ivison
Louisa Nolan Omar Almaini
Suzie Scott Bob Mann

2. Outline 1. Black-hole - Host-spheroid connection at low z
2. Out to high z with active black holes
3. Out to high z with quiescent black holes
4. Coupled black hole and spheroid formation at high z

3. HST studies of low-z quasar hosts
RLQ
RQQ RG

4. Results - host morphologies
Spheroid |
Disc |
All are ellipticals except
2 low-luminosity RQQs and

5. Host morphology as function of nuclear power
Schade et al. (2000)
+ McLure et al. (1999)
& Dunlop et al. (2001)

6. Results - Kormendy relation
Slope = 2.9
cf `normal ellipticals’
Slope = 2.95
(Kormendy 1985)

7. A detailed look at the Kormendy relation
Discy ellipticals
Faber et al. 1997
Boxy ellipticals
Faber et al. 1997
ULIRGS
Genzel et al. 2001

8. Cluster Environments - up to Abell Class 1/2
And biggest hosts are consistent with this, with scalelengths ~ 25 kpc
We know of no low-z quasar hosts
as big as first ranked galaxies in
Abell Class 3 or 4 clusters
e.g. Abell re = 100 kpc
Abell re = 75 kpc
but such clusters are so rare that
even an all-sky survey in redshift
band 0.1 < z < 0.25 would contain
< 1500 Abell Class 3 or 4 clusters
Therefore no quasars expected
in these rare environments at low z
because only 1 in black holes
are active

9. Ages of quasar hosts
Nolan et al. 2000

10. Ages of quiescent ellipticals

11. Black hole masses of quasars - now believable
McLure & Dunlop 2001
Dunlop et al. 2001

12. Summary of Part 1
Low-z quasars are powered by black holes with M > 5 x 108 solar masses
These black holes live in spheroids of expected mass Mbh = Msph
Spheroids have structural parameters and environments like boxy ellipticals
Boxy ellipticals and quasar hosts appear old/evolved (12-13 Gyr)
Quasar hosts in general not the result of recent ULIRG mergers
But more moderate mass spheroids/AGN may be (e.g. seyferts)
Low-z AGN = random activation of 1 in present-day black holes

13. Want to trace black-hole spheroid link out to high z - confine attention to high-mass end Look at hosts of known active black holes or Trace evolution of massive spheroids, and look for AGN activity in them

14. 2. Hosts of active black holes out to high z
Kormendy relations of 3CR radio galaxies at z = 0.2 and z = 1
- consistent with passive evolution (McLure & Dunlop 2000)

15. Age of oldest hosts at z = 1.5
Keck spectroscopy of red radio galaxies at z = 1.5
> 3 Gyr at z = 1.5
means formation z = 5
Dunlop et al. (1996)
Peacock et al. (1999)
Nolan et al. (2001)

16. Change in K-band morphology at z > 3
Van Breugel et al. (2001)

17. Radio galaxies are dusty at z > 3
L850 grows approximately as (1+z)3
(Archibald et al. 2001)

18. SCUBA imaging of radio galaxies
Star-formation around z = 4 radio galaxies also prolific?
SCUBA image of 4C41.17, z = 3.8
(Ivison, Dunlop, et al. 2000)

19. Summary of Part 2 z = 0 z = 1 z = 1.5 z = 2 z = 3
Host Size kpc kpc ? ? Messy
Host Age Gyr Gyr Gyr ? Star-forming
% BH active

20. 3. Hosts of passive black holes out to high z
There have been claims that massive ellipticals don’t exist at z > 1
(e.g. Kauffman & Charlot 1998)
But they could be hiding due to
1. Surface brightness bias - hard to recognize big extended ellipticals
2. Being very passive at intermediate z
3. Being dust-enshrouded during peak of SF activity at high z

21. Passively evolving ellipticals at 1 < z < 2
How many quiescent massive ellipticals are there today with masses
comparable to radio galaxies?
Integrate K-band luminosity function for L > L* gives x 10-5 Mpc-3
Substantial numbers of 53W091/53W069 analogues have now been found
specifically surface density of objects with K < 18.5 and R-K > 5.3 is
350 per sq. degree (Daddi et al. 2000, 2001)
Assuming 1 < z < 2, this gives a comoving number density = 3 x 10-5 Mpc-3

22. Higher z - SCUBA surveys?
New results on surface density of bright SCUBA sources from 8mJy survey
(Scott et al. 2001)
Assuming most of these lie at z > 2
comoving number density of things
forming > 1000 solar masses
of stars per year
= x 10-5 Mpc-3

23. Are bright SCUBA sources high-z proto-ellipticals?
SED constraints say z > 2
Identifications look like high-z radio galaxies Lutz et al. (2001)

24. Summary of Part 3 Question - Why are SCUBA sources not all bright AGN?
Number density of massive ellipticals at z = = x 10-5 Mpc-3
Number density of comparably massive EROs at z ~ = 3 x 10-5 Mpc-3
Number density of bright SCUBA sources at z > = x 10-5 Mpc-3
Question - Why are SCUBA sources not all bright AGN?
And why are only high-z AGN SCUBA sources?

25. 4. Spheroid and black hole formation
Simple model of collapsing gas sphere of baryonic mass 1012 solar masses
within dark matter halo
1-D chemical-evolution/hydro code with 100 zones Friaca et al. 1999,
Star-formation, SN rate, metal production, cooling etc Jimenez et al. 1999
Models predict
decline of gas
growth of stars
and rise and fall of dust
in starburst commencing
at z = 5

26. Rate of mass consumption by black hole
Assume all mass dumped into central 100pc available to black hole
Assuming initial black-hole mass =10 solar masses
- get Eddington limited growth for most of first Gyr

27. Growth of black hole

28. AGN output compared with dust mass