1. Quasar Surveys -- From Sloan to SNAP
Xiaohui Fan
University of Arizona
May 17, 2004

2. Quasars and Galaxy Formation
The Study of Quasars Probes:
Accretion history of BHs in the Universe
Relation of BH growth and galaxy evolution
State of intergalactic medium
History of reionization  probing the end of cosmic dark ages

3. Quasar Surveys in the last decade
1996: Veron-Veron catalog
8609 quasars
2833 AGNs
2dF quasar survey (1997 – 2002)
25,000 quasars at z<2.8
SDSS quasar survey (1999 – 2005+)
Currently: >50,000 quasars
Goal: 100,000 quasars
z<6.5
Next?
Fainter magnitude
Higher redshift

4. Outline Main Results from SDSS and 2dF surveys
Evolution of Quasar Luminosity Function
Quasar Clustering
Early Growth of Supermassive Black Holes
Constraints on the Reionization Epoch
Expectation of Future Wide-field Space Surveys
Photometric redshift estimates for quasars
Evolution of faint quasars at high-redshift
Prospects of finding quasars at z = 6 – 10

5. 17,000 Quasars from the SDSS Data Release One5
Ly a 3 2
CIV
redshift
CIII 1
MgII
OIII Ha
wavelength
4000 A
9000 A

6. Evolution of Quasar Luminosity Function
SFR of Normal Gal
Exponential decline of quasar
density at high redshift, different
from normal galaxies

7. Evolution of LF shape
At low-z: 2dF results show that LF is well fit by double power law with pure luminosity evolution
At z~4: quasar luminosity function much FLATTER than LF at z~2

8. Clustering of Quasars What does quasar clustering tell us?
Bias factor of quasars  average DM halo mass
A biased large scale power spectrum at high-z
Clustering probably provides the most effective probe to the statistical properties of quasar host galaxies at high-redshift
Combining with quasar density  quasar lifetime and duty cycle

9. Large Scale Distribution of Quasars
SDSS
2dF

10. Quasar Two-point Correlation Function from SDSS at z<2.5
Van den Berk et al. in preparation

11. Evolution of Quasar Clustering
Fan et al. in preparation

12. The Highest Redshift Quasars Today
z>4: ~700 known
z>5: ~30
z>6: 7
SDSS i-dropout Survey:
By Spring 2004: 6000 deg2 at zAB<20
Fourteen luminous quasars at z>5.7
20 – 40 at z~6 expected in the whole survey
Total Discoveries
SDSS Discoveries

14. Quasar Density at z~6 Based on nine z>5.7 quasars:
Density declines by a factor of ~20 from z~3
It traces the emergence of the earliest supermassive BHs in the Universe
Cosmological implication
MBH~ Msun
Mhalo ~ 1013 Msun
How to form such massive galaxies and assemble such massive BHs in less than 1Gyr??
The rarest and most biased systems at early times
Using Eddington argument, the initial assembly of the system must start at z>>10
 co-formation and co-evolution of the earliest SBH and galaxies
Fan et al. 2004

15. The Lack of Evolution in Quasar Intrinsic Spectral Properties
Quasars are boring…
The Lack of Evolution in Quasar Intrinsic Spectral Properties
Ly a NV OI
Ly a forest
SiIV
High-z quasars and their environments matures early on

16. Early Growth of Supermassive Black Holes
Formation timescale
(assuming Eddington)
Vestergaard 2004
Dietrich and Hamann 2004
Billion solar mass BH indicates very early
Growth of BHs in the Universe

17. Black Hole Mass Function
Mass function for different redshifts
Vestergaard et al in prep

18. Chemical Enrichment at z>>6?
Strong metal emission  consistent with supersolar metallicity
NV emission  multiple generation of star formation
Fe II emission  might be from metal-free Pop III
Fan et al. 2001
Barth et al. 2003

19. in the highest-redshift quasar: Dust mass: 108 – 109Msun
Submm and CO detection
in the highest-redshift quasar:
Dust mass: 108 – 109Msun
H2 mass: 1010Msun
Star formation rate: 103/yr
co-formation of SBH and
young galaxies

20. reionization
From Avi Loeb

21. Gunn-Peterson troughs confirmed by new z>6 quasars

22. Strong Evolution of Gunn-Peterson Optical Depth
Transition at z~6?
Fan et al. 2003

23. Constraining the Reionization Epoch
Neutral hydrogen fraction
Volume-averaged HI fraction increased by >100 from z~3 to z~6
Mass-averaged HI fraction > 1%
At z~6:
Last remaining neutral regions are being ionized
The universe is >1% neutral
Marks the end of reionization epoch??
mass ave.
vol. ave
Fan et al. in prep

24. The end of dark ages
CMB polarization shows: substantial ionization by z~17:
Combining GP with CMB  reionization history:
Reionization last from 20 to 6? (600 million years) ?
Reionization is not a phase transition
Reionization seems to be more complicated by the simplest theory

25. Quasar Survey in Space?
Limitations of current generation quasar surveys:
Shallow: Only probing the most luminous quasars  majority of high-z quasars have not been detected!
Evolution of faint quasars unknown
Majority of UV background at high-z not detected yet
Optical: Highest redshift limit is ~6.5

26. Quasar Survey in Space? Deep: Infrared: Breaking the z=7 Barrier
Sampling the entire quasar population
Probing “normal” BHs in average galaxies
Possible with LSST
Infrared: Breaking the z=7 Barrier
Emergence of the first luminous quasars in the Universe
Probing the history of the cosmic reionization
Key issue:
How effectively can quasar be selected photometrically, without a large spectroscopic survey?

27. Quasar Photo-z? Lyman break technical efficient at z>3
At low-z, strong emission line passing through pass-bands causes bumps in the color-z relation
Esp. 3000A bump

28. Quasar Photo-z using SDSS photometry
Weinstein et al. 2004, Richards et al show:
With good (sigma <0.05) photometry
86% photo-z correct to within 0.3
65% photo-z correct to within 0.1
95% of photometrically-selected quasars are real quasars confirmed by spectroscopy

29. Photo-z selected quasar number counts

30. X-ray vs. Optical LF There is very little overlap…
do faint quasars evolve
differently from luminous quasars?

31. Evolution of Quasar/AGN Density
Optical, high-luminosity
X-ray, low-luminosity

32. Luminosity Function: AGNs and QSOs
z=0
Hao et al. 2004

33. Probing the end of dark ages
Panoramic:
7000 sq.deg, effective selection down to 24.5
z~3 quasars: 200 – 400 per sq. deg
Hundreds of z~6 quasars
Maybe 10 luminous quasars at z = 9 – 10?

34. Probing Reionization History
SNAP Spectrograph
Double reionization model:
Early reionization at z>10
Second dark age at z<8.5

35. Quasar Astrophysics Large scale structure  host galaxy masses
Quasar clustering
Quasar weak lensing
Strong lensing
Variability  revebretion mapping and BH mass
High resolution imaging of host galaxies

36. GEMS/COMBO-17: quasar host galaxies
Kormendy relation from
GEMS host galaxies
Wisotzki et al. 2004

37. Summary Current quasar survey shows
Strong evolution of luminous quasar number density
Strong clustering of luminous quasars
Existence of billion solar mass BHs at z~6
Emergence of Gunn-Peterson effect indicates the end of reionization epoch by z~6
A wide-field space-based quasar survey will
Probe the evolution of faint quasars and the evolution of UV background at high-z
Reveal the evolution of first luminous quasars in the Universe
Map the history of reionization at z = 6 – 10
Relation between quasar activity and galaxy formation

38. Courtesy of Arizona graduate students
SNAPS
Courtesy of Arizona graduate students

39. SDSS: Structure Function

40. Structure function turnover

41. Strong Evolution of Gunn-Peterson Optical Depth
Transition at z~6?
Fan et al. 2003