The Most Distant Quasars Xiaohui Fan University of

The Most Distant Quasars Xiaohui Fan University of Arizona June 7, 2010 Collaborators: Brandt, Carilli, de Rosa, Jiang, Kurk, Richards, Schneider, Shen, Strauss, Vestergaard, Walter, Wang Background: 46, 420 Quasars from the SDSS Data Release Three

Quasar of the day • Last night’s astro-ph: Willott et al. new highestredshift quasar at z=6. 44

Quest to the Highest Redshift

30 at z>6 60 at z>5. 5 >100 at z>5

Key Questions • When did the first supermassive BH form? – Measurement of quasar luminosity function and BH mass at z>6 • When did the first quasar form? – (lack of ? ) Evolution of spectral energy distribution • Co-evolution of the earliest BHs and galaxies – Does M-σ relation exist at z>6?

Formation of z~6 quasars from hierarchical mergers Li et al. 2007

Theorists Tell us • These luminous z~6 quasars: – The most massive system in early Universe – Living in the densest environment – BH accreting at Eddington – Host galaxies have ULIRG properties with maximum starburst Li et al. 2007

Quasar Evolution at z~6 • • • Strong density evolution – Density declines by a factor of ~40 from between z~2. 5 and z~6 Black hole mass measurements – MBH~109 -10 Msun – Mhalo ~ 1012 -13 Msun – rare, 5 -6 sigma peaks at z~6 (density of 1 per Gpc 3) Luminosity function at z~6 – Bright end slope steep – LF breaks at M~-25 • Not likely significant contributor to reionization budget • bad news for deep quasar surveys Fan et al. 2006 Low-z z~6 Willott et al. 2010

Eddington Ratios in z~6 Quasars z~6 quasars • Quasar BH mass measured from near-IR spectroscopy in CIV and Mg. II regions • On average: at or close to Eddington accretion See De Rosa poster

Are there luminous quasars at z>>7 • Black Holes do not grow arbitrarily fast – Accretion onto BHs dicitated by Eddington Limit – E-folding time of maximum supermassive BH growth: 40 Myr – At z=7: age of the universe: 800 Myr = maximum 20 e-folding • Billion solar mass BH at z>7 • Non-stop, maximum accretion from 100 solar mass BHs at z=15 (collapse of first stars in the Universe) • Theoretically difficult formation of z>7 billion solar mass BHs by Eddington-limited accretion from stellar seeds • What if we find them: – Direct collapse of “intermediate” mass BHs? – More efficient accretion model “super-Eddington”?

non-evolution of quasar (black hole) emission z~6 composite Low-z composite Ly a NV Ly a forest OI Si. IV XF et al. 2010 • • • Jiang, XF et al. 2008 Rapid chemical enrichment in quasar vicinity Quasar env has supersolar metallicity : no metallicity evolution High-z quasars are old, not yet first quasars, and live in metally enriched env similar to centers of massive galaxies

When did the first quasar form? Dust: emitting in infrared radiation from X-ray to radio as a result of black hole accretion and growth

Hot dust in z~6 Quasars • Lack of evolution in UV, emission line and X-ray disk and emission line regions form in very short time scale • But how about dust? Timescale problem: running out of time for AGB dust • Spitzer observations of z~6 quasars: probing hot dust in dust torus (T~1000 K) • Three unusual SEDs among ~30 objects observed. dust Jiang, XF et al. 2006, 2010 No hot dust? ?

Disappearance of Dust Torus at z~6? typical J 0005 3. 5 m 4. 8 m 5. 6 m 8. 0 m 16 m 24 m • quasars with no hot dust • Spitzer SEDs consistent with disk continuum only • No similar objects known at low-z • no enough time to form hot dust tori? Or formed in metal-free environment? Jiang, XF et al. 2010

Epoch of first quasars? Dust/Bolometric Dust-free quasars: Dust/Bolometric • Only at the highest redshift • With the smallest BH mass • First generation supermassive BHs from metal-free environment? • How are they related to Pop. III? BH mass Jiang, XF et al. 2010

Probing quasar host galaxies at high-z [OIII] Direct imaging: hard! Radio/sub-mm! CO

Star Formation in z~6 Quasars • 30% of z~6 quasars detected at 1 m. Jy level in 1 -mm -> – LFIR~ 1013 Lsun – T~50 K – SFR~1000 Msunyr-1 (if dust heated by SB) • New CO observations – eight quasars detected in CO – Probing ISM properties and host galaxy masses Wang et al. 2008, 2009

Maximum starburst in z=6. 4 quasar ? • Spatially resolved CO and [CII] emissions: – Size: ~1. 5 kpc from [CII] (0. 3”) – Continuum has >50% extended component: SB heating? – Star formation rate of: ~1000 Msunyr-1 kpc-2 • Eddington limited maximum star formation rate (Thompson et al. )? • Gas supply exhaused over a few tdyn – Similar SF intensity to Arp 200 but 100 times larger! • Dynamical mass: 1 kpc Walter et al. 2004 – CO/CII line width ~300 km/s – Dynamical mass ~1011 Msun? – BH formed earlier than completion of galaxy assembly? – Walter et al. 2009

Do z~6 Quasars Live in the Densest Environments? • High-redshift quasars are strongly clustered Shen et al. 2007 • But efforts to look for overdensity around z~6 quasars have mostly produced non-results (Willott et al. , Kim et al. , Kurk et al. , Zheng et al. )

Do z~6 Quasars Live in the Densest Environments? • Non-detection of significant overdensity around z~6 quasars: – Quasars suppress dwarf galaxy formation? – Quasar hosts are not massive? – Needs deeper and wider surveys Overzier et al. 2008

Conclusions and Questions • Rapid evolution of quasar density at z~6 – Are we closing in to the epoch of the earliest SBH formation? • First hot dust at z~6 – Are we closing in to the epoch of first AGN structure? • Luminous quasars seem to live in modest environments – Narrow CO line width small host mass – No significant overdensity of galaxies – How closely tied are the earliest SBHs and galaxies? Or are we just picking up early starters in term of BH accretion in the most luminous quasars? • Important changes at z~6: needs to push for higher redshift and lower luminosities

Quest to the Highest Redshift

Quest to the Highest Redshift 090423 080913 050904 000131 GRBs 970228

Probing Reionization History WMAP