Quasar Surveys -- From Sloan to SNAP

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Quasar Surveys-- From Sloan to SNAP

• Xiaohui Fan
• University of Arizona
• May 17, 2004

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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

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Quasar Surveys in the last decade

• 1996 Veron-Veron catalog
• 8609 quasars
• 2833 AGNs
• 2dF quasar survey (1997 2002)
• 25,000 quasars at zlt2.8
• SDSS quasar survey (1999 2005)
• Currently gt50,000 quasars
• Goal 100,000 quasars
• zlt6.5
• Next?
• Fainter magnitude
• Higher redshift

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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

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17,000 Quasars from the SDSS Data Release One
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Ly a
3
2
CIV
redshift
CIII
1
MgII
OIII
Ha
0
wavelength
4000 A
9000 A
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Evolution of Quasar Luminosity Function
SFR of Normal Gal
Exponential decline of quasar density at
high redshift, different from normal galaxies


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Evolution of LF shape

• At low-z 2dF results show that LF is well fit by
  double power law with pure luminosity evolution
• At z4 quasar luminosity function much FLATTER
  than LF at z2

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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

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Large Scale Distributionof Quasars
SDSS
2dF
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Quasar Two-point Correlation Function from SDSS
at zlt2.5
Van den Berk et al. in preparation
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Evolution of Quasar Clustering
Fan et al. in preparation
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The HighestRedshift Quasars Today

• zgt4 700 known
• zgt5 30
• zgt6 7
• SDSS i-dropout Survey
• By Spring 2004 6000 deg2 at zABlt20
• Fourteen luminous quasars at zgt5.7
• 20 40 at z6 expected in the whole survey

Total Discoveries
SDSS Discoveries
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Quasar Density at z6

• Based on nine zgt5.7 quasars
• Density declines by a factor of 20 from z3
• It traces the emergence of the earliest
  supermassive BHs in the Universe
• Cosmological implication
• MBH109-10 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 zgtgt10
• ? co-formation and co-evolution of the earliest
  SBH and galaxies

Fan et al. 2004
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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
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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
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Black Hole Mass Function
Mass function for different redshifts
Vestergaard et al. 2004 in prep
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Chemical Enrichment at zgtgt6?

• 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
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• 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

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reionization
From Avi Loeb
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Gunn-Peterson troughs confirmed by new zgt6 quasars
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Strong Evolution ofGunn-Peterson Optical Depth
Transition at z6?
Fan et al. 2003
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Constraining the Reionization Epoch

• Neutral hydrogen fraction
• Volume-averaged HI fraction increased by gt100
  from z3 to z6
• Mass-averaged HI fraction gt 1
• At z6
• Last remaining neutral regions are being ionized
• The universe is gt1 neutral
• Marks the end of reionization epoch??

mass ave.
vol. ave
Fan et al. in prep
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The end of dark ages

• CMB polarization shows substantial ionization by
  z17
• 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

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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

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Quasar Survey in Space?

• Deep
• Sampling the entire quasar population
• Probing normal BHs in average galaxies
• Possible with LSST
• Infrared Breaking the z7 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?

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Quasar Photo-z?

• Lyman break technical efficient at zgt3
• At low-z, strong emission line passing through
  pass-bands causes bumps in the color-z relation
• Esp. 3000A bump

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Quasar Photo-z usingSDSS photometry

• Weinstein et al. 2004, Richards et al. 2004 show
• With good (sigma lt0.05) 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

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Photo-z selected quasar number counts
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X-ray vs. Optical LF

• There is very little overlap
• do faint quasars evolve
• differently from luminous quasars?
  

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Evolution of Quasar/AGN Density
Optical, high-luminosity
X-ray, low-luminosity
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Luminosity Function AGNs and QSOs
z0
Hao et al. 2004
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Probing the end of dark ages

• Panoramic
• 7000 sq.deg, effective selection down to 24.5
• z3 quasars 200 400 per sq. deg
• Hundreds of z6 quasars
• Maybe 10 luminous quasars at z 9 10?

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Probing Reionization History
SNAP Spectrograph

• Double reionization model
• Early reionization at zgt10
• Second dark age at zlt8.5

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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

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

• Current quasar survey shows
• Strong evolution of luminous quasar number
  density
• Strong clustering of luminous quasars
• Existence of billion solar mass BHs at z6
• Emergence of Gunn-Peterson effect indicates the
  end of reionization epoch by z6
• 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

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SNAPS
Courtesy of Arizona graduate students
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SDSS Structure Function
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Structure function turnover
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Strong Evolution ofGunn-Peterson Optical Depth
Transition at z6?
Fan et al. 2003
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