quasar surveys -- from sloan to snap
DESCRIPTION
Quasar Surveys -- From Sloan to SNAP. Xiaohui Fan University of Arizona May 17, 2004. 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 - PowerPoint PPT PresentationTRANSCRIPT
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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 z<2.8
• SDSS quasar survey (1999 – 2005+)– Currently: >50,000 quasars– Goal: 100,000 quasars– z<6.5
• Next?– Fainter magnitude– Higher redshift
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17,000 Quasars from the SDSS Data Release One
wavelength4000 A 9000 A
reds
hift
0
1
2
3
5Ly a
CIV
CIII
MgII
HaOIII
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Evolution of Quasar Luminosity Function
Exponential decline of quasar density at high redshift, different from normal galaxies
SFR of Normal Gal
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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 z~4: quasar luminosity function much FLATTER than LF at z~2
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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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Quasar Two-point Correlation Function from
SDSS at z<2.5
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
• 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
SDSS DiscoveriesTotal Discoveries
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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~109-10 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 z>>10
co-formation and co-evolution of the earliest SBH and galaxies
Fan et al. 2004
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Quasars are boring…
NVOI SiIV
Ly a
Ly a forest
High-z quasars and their environments matures early on
The Lack of Evolution in Quasar Intrinsic Spectral Properties
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Early Growth of Supermassive Black Holes
Vestergaard 2004 Dietrich and Hamann 2004
Billion solar mass BH indicates very early Growth of BHs in the Universe
Formation timescale (assuming Eddington)
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Mass function for different redshifts
Black Hole Mass Function
Vestergaard et al. 2004 in prep
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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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From Avi Loeb
reionization
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Gunn-Peterson troughs confirmed by new z>6 quasars
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Strong Evolution ofGunn-Peterson Optical Depth
Fan et al. 2003
Transition at z~6?
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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??
Fan et al. in prep
mass ave.
vol. ave
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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
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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 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?
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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
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Quasar Photo-z usingSDSS photometry
• Weinstein et al. 2004, Richards et al. 2004 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
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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
X-ray, low-luminosity Optical, high-luminosity
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Luminosity Function: AGNs and QSOs
Hao et al. 2004
z=0
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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?
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Probing Reionization History
Double reionization model:• Early reionization at z>10• Second dark age at z<8.5
SNAP Spectrograph
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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 fromGEMS 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 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
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Courtesy of Arizona graduate students
SNAPS
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SDSS: Structure Function
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Structure function turnover
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Strong Evolution ofGunn-Peterson Optical Depth
Fan et al. 2003
Transition at z~6?
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