Imaging of SDSS z > 6 Quasar Fields: Gravitational Lensing, Companion Galaxies, and the Host Dark Matter Halos

We have undertaken deep optical imaging observations of three 6.2 < z < 6.5 quasar fields in the i' and z' filters. These data are used to search for foreground galaxies that are gravitationally lensing the quasars and distant galaxies physically associated with the quasars. Foreground galaxies are found closer than 5'' to the lines of sight of two of the three quasars. However, the faintness of these galaxies suggests that they have fairly low masses and provide only weak magnifications (μ ≲ 1.1). No convincing galaxies physically associated with the quasars are found, and the number of i'-band dropouts is consistent with that found in random fields. We consider the expected dark matter halo masses that host these quasars under the assumption that a correlation between black hole mass and dark matter halo mass exists. We show that the steepness of the high-mass tail of the halo mass function at this redshift, combined with realistic amounts of scatter in this correlation, leads to expected halo masses substantially lower than previously believed. This analysis can explain the lack of companion galaxies found here and the low dynamical mass recently published for one of the quasars.

[1]  S. Bharadwaj,et al.  A two-dimensional analysis of percolation and filamentarity in the Sloan Digital Sky Survey Data Release One , 2005 .

[2]  S. Djorgovski,et al.  Evidence of Primordial Clustering around the QSO SDSS J1030+0524 at z = 6.28 , 2005, astro-ph/0502223.

[3]  K. Adelberger.  Estimating the Galaxy Correlation Length r0 from the Number of Galaxy Pairs with Similar Redshifts , 2004, astro-ph/0412397.

[4]  Xiaohui Fan,et al.  Resolved Molecular Gas in a Quasar Host Galaxy at Redshift z = 6.42 , 2004, astro-ph/0410229.

[5]  Mamoru Doi,et al.  The Subaru Deep Field: The Optical Imaging Data , 2004 .

[6]  S. Okamura,et al.  A Strong Lyα Emitter at z = 6.33 in the Subaru Deep Field Selected as an i'-Dropout , 2004, astro-ph/0408255.

[7]  O. López-Cruz,et al.  The Color-Magnitude Effect in Early-Type Cluster Galaxies , 2004, astro-ph/0407630.

[8]  G. Hasinger,et al.  Photometric Redshift of X-Ray Sources in the Chandra Deep Field-South , 2004, astro-ph/0406482.

[9]  Z. Haiman,et al.  Gravitational Lensing Magnification without Multiple Imaging , 2004, astro-ph/0405143.

[10]  I. Smail,et al.  Submitted to ApJ Preprint typeset using L ATEX style emulateapj v. 6/22/04 CLUSTERING OF SUBMILLIMETER-SELECTED GALAXIES , 2004 .

[11]  R. Bouwens,et al.  Star Formation at z ~ 6: The Hubble Ultra Deep Parallel Fields , 2004 .

[12]  A. Loeb,et al.  Calibrating the Galaxy Halo-Black Hole Relation Based on the Clustering of Quasars , 2004, astro-ph/0403714.

[13]  Cambridge,et al.  The star formation rate of the Universe at z~ 6 from the Hubble Ultra-Deep Field , 2004, astro-ph/0403223.

[14]  R. Bouwens,et al.  Star Formation at z~6: The UDF-Parallel ACS Fields , 2004, astro-ph/0403167.

[15]  M. Giavalisco,et al.  A Deep Wide-Field, Optical, and Near-Infrared Catalog of a Large Area around the Hubble Deep Field North , 2003, astro-ph/0312635.

[16]  R. Somerville,et al.  High-redshift quasars and the supermassive black hole mass budget: constraints on quasar formation models , 2003, astro-ph/0311008.

[17]  A. Loeb,et al.  Unusually Large Fluctuations in the Statistics of Galaxy Formation at High Redshift , 2003, astro-ph/0310338.

[18]  Neta A. Bahcall,et al.  A Snapshot Survey for Gravitational Lenses among z ≥ 4.0 Quasars. II. Constraints on the 4.0 < z < 5.4 Quasar Population , 2003, astro-ph/0309274.

[19]  G. Bruzual,et al.  Stellar population synthesis at the resolution of 2003 , 2003, astro-ph/0309134.

[20]  S. M. Fall,et al.  The Great Observatories Origins Deep Survey: Initial Results from Optical and Near-Infrared Imaging , 2003, astro-ph/0309105.

[21]  Padova,et al.  Color-selected Galaxies at z ≈ 6 in the Great Observatories Origins Deep Survey , 2003, astro-ph/0309070.

[22]  Edinburgh,et al.  Quasars as probes of the submillimetre cosmos at z > 5 — I. Preliminary SCUBA photometry , 2003, astro-ph/0308132.

[23]  M. A. Strauss,et al.  Molecular gas in the host galaxy of a quasar at redshift z = 6.42 , 2003, Nature.

[24]  K. M. Menten,et al.  High-excitation CO in a quasar host galaxy at z = 6.42 , 2003, astro-ph/0307408.

[25]  T. Nagao,et al.  Are Two z ∼ 6 Quasars Gravitationally Lensed? ∗ , 2003, astro-ph/0306450.

[26]  Xiaohui Fan,et al.  Dust emission from the most distant quasars , 2003, astro-ph/0305116.

[27]  A. Loeb,et al.  Self-regulated Growth of Supermassive Black Holes in Galaxies as the Origin of the Optical and X-Ray Luminosity Functions of Quasars , 2003, astro-ph/0304156.

[28]  R. McLure,et al.  A 3 × 109 M☉ Black Hole in the Quasar SDSS J1148+5251 at z = 6.41 , 2003, astro-ph/0303062.

[29]  R. Nichol,et al.  Early-type Galaxies in the Sloan Digital Sky Survey. II. Correlations between Observables , 2003, astro-ph/0301624.

[30]  V. Narayanan,et al.  A Survey of z > 5.7 Quasars in the Sloan Digital Sky Survey. II. Discovery of Three Additional Quasars at z > 6 , 2003, astro-ph/0301135.

[31]  E. al.,et al.  The Discovery of Two Lyman α Emitters beyond Redshift 6 in the Subaru Deep Field , 2003 .

[32]  S. Okamura,et al.  SDSSp J104433.04−012502.2 at z=5.74 is Gravitationally Magnified by an Intervening Galaxy , 2002, astro-ph/0211388.

[33]  M. Jarvis,et al.  Near-infrared imaging and the K—z relation for radio galaxies in the 7C Redshift Survey , 2002, astro-ph/0209439.

[34]  M. Parrinello,et al.  Magnification of light from many distant quasars by gravitational lenses , 2002, Nature.

[35]  Z. Haiman,et al.  Constraining the Redshift z ~ 6 Quasar Luminosity Function Using Gravitational Lensing , 2002, astro-ph/0206441.

[36]  L. Ferrarese.  Beyond the Bulge: A Fundamental Relation between Supermassive Black Holes and Dark Matter Halos , 2002, astro-ph/0203469.

[37]  S. Tremaine,et al.  The Slope of the Black Hole Mass versus Velocity Dispersion Correlation , 2002, astro-ph/0203468.

[38]  A. Loeb,et al.  Gravitational Lensing of the Sloan Digital Sky Survey High-Redshift Quasars , 2002, astro-ph/0203119.

[39]  S. Tremaine,et al.  Observational constraints on growth of massive black holes , 2002, astro-ph/0203082.

[40]  J. Kneib,et al.  A Redshift z = 6.56 Galaxy behind the Cluster Abell 370 , 2002, astro-ph/0203091.

[41]  D. Redding,et al.  Imaging of z ∼ 2 QSO Host Galaxies with the Hubble Space Telescope , 2002, astro-ph/0202401.

[42]  L. Cowie,et al.  Approaching Reionization: The Evolution of the Lyα Forest from z = 4 to z = 6 , 2002, astro-ph/0202165.

[43]  J. Dunlop,et al.  Quasars, their host galaxies and their central black holes , 2001, astro-ph/0108397.

[44]  V. Narayanan,et al.  A Survey of z > 5.8 Quasars in the Sloan Digital Sky Survey. I. Discovery of Three New Quasars and the Spatial Density of Luminous Quasars at z ∼ 6 , 2001, astro-ph/0108063.

[45]  D. Calzetti,et al.  NICMOS Imaging of the Host Galaxies of z ~ 2-3 Radio-quiet Quasars , 2000, astro-ph/0011330.

[46]  A. Loeb,et al.  In the Beginning: The First Sources of Light and the Reionization of the Universe , 2000, astro-ph/0010468.

[47]  University of Oxford,et al.  A NICMOS imaging study of high-z quasar host galaxies , 2000, astro-ph/0010007.

[48]  Ralf Bender,et al.  A Relationship between Nuclear Black Hole Mass and Galaxy Velocity Dispersion , 2000, astro-ph/0006289.

[49]  D. Merritt,et al.  A Fundamental Relation between Supermassive Black Holes and Their Host Galaxies , 2000, astro-ph/0006053.

[50]  A. Fabian.  THE OBSCURED GROWTH OF MASSIVE BLACK HOLES , 1999, astro-ph/9908064.

[51]  Ravi K. Sheth Giuseppe Tormen.  Large scale bias and the peak background split , 1999, astro-ph/9901122.

[52]  L. Pozzetti,et al.  The Star Formation History of Field Galaxies , 1997, astro-ph/9708220.

[53]  S. Tremaine,et al.  The Demography of Massive Dark Objects in Galaxy Centers , 1997, astro-ph/9708072.

[54]  E. Bertin,et al.  SExtractor: Software for source extraction , 1996 .

[55]  M. Rees,et al.  Pregalactic evolution in cosmologies with cold dark matter , 1986 .

[56]  N. Kaiser.  On the spatial correlations of Abell clusters , 1984 .