Iron Emission in the z = 6.4 Quasar SDSS J114816.64+525150.3

We present near-infrared J- and K-band spectra of the z = 6.4 quasar SDSS J114816.64+525150.3 obtained with the NIRSPEC spectrograph at the Keck II telescope, covering the rest-frame spectral regions surrounding the C IV λ1549 and Mg II λ2800 emission lines. The iron emission blend at rest wavelength 2900-3000 Å is clearly detected, and its strength appears nearly indistinguishable from that of typical quasars at lower redshifts. The Fe II/Mg II ratio is also similar to values found for lower redshift quasars, demonstrating that there is no strong evolution in Fe/α broad-line emission ratios even out to z = 6.4. In the context of current models for iron enrichment from Type Ia supernovae (SNe Ia), this implies that the SN Ia progenitor stars formed at z ≳ 10. We apply the scaling relations of Vestergaard and of McLure & Jarvis to estimate the black hole mass from the widths of the C IV and Mg II emission lines and the ultraviolet continuum luminosity. The derived mass is in the range (2-6) × 109 M☉, with an additional uncertainty of a factor of 3 due to the intrinsic scatter in the scaling relations. This result is in agreement with the previous mass estimate of 3 × 109 M☉ by Willott, McLure, & Jarvis and supports their conclusion that the quasar is radiating close to its Eddington luminosity.

[1]  B. Kogut.  The Global Internet Economy , 2003 .

[2]  E. Verner,et al.  Revisited Abundance Diagnostics in Quasars: Fe II/Mg II Ratios , 2003, astro-ph/0306533.

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

[4]  D. Kelson.  Optimal Techniques in Two‐dimensional Spectroscopy: Background Subtraction for the 21st Century , 2003, astro-ph/0303507.

[5]  Robert H. Becker,et al.  Probing the Ionization State of the Universe at z > 6 , 2003, astro-ph/0303476.

[6]  K. Korista,et al.  Iron Emission in z ≈ 6 QSOS , 2003, astro-ph/0303424.

[7]  J. Shields,et al.  Quasar Elemental Abundances at High Redshifts , 2003, astro-ph/0302494.

[8]  J. Brinkmann,et al.  Determining the Lensing Fraction of SDSS Quasars: Methods and Results from the Early Data Release , 2003, astro-ph/0301464.

[9]  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.

[10]  H Germany,et al.  A Method of Correcting Near‐Infrared Spectra for Telluric Absorption , 2002, astro-ph/0211255.

[11]  Piero Madau,et al.  The Assembly and Merging History of Supermassive Black Holes in Hierarchical Models of Galaxy Formation , 2002, astro-ph/0207276.

[12]  A. Loeb,et al.  A Physical Model for the Luminosity Function of High-Redshift Quasars , 2002, astro-ph/0206154.

[13]  R. McLure,et al.  Measuring the black hole masses of high-redshift quasars , 2002, astro-ph/0204473.

[14]  M. SubbaRao,et al.  Broad Emission-Line Shifts in Quasars: An Orientation Measure for Radio-Quiet Quasars? , 2002, astro-ph/0204162.

[15]  B. Peterson,et al.  Determining Central Black Hole Masses in Distant Active Galaxies and Quasars. II. Improved Optical and UV Scaling Relationships , 2002, astro-ph/0601303.

[16]  M. Doi,et al.  Fe II/Mg II Emission-Line Ratios of QSOs within 0 < z < 5.3 , 2002 .

[17]  S. Woosley,et al.  The Nucleosynthetic Signature of Population III , 2001, astro-ph/0107037.

[18]  M. Dietrich,et al.  High-Redshift Quasars and Star Formation in the Early Universe , 2001, astro-ph/0109208.

[19]  E. al.,et al.  Composite Quasar Spectra from the Sloan Digital Sky Survey , 2001, astro-ph/0105231.

[20]  F. Matteucci,et al.  On the Typical Timescale for the Chemical Enrichment from Type Ia Supernovae in Galaxies , 2001, astro-ph/0105074.

[21]  B. Wilkes,et al.  An Empirical Ultraviolet Template for Iron Emission in Quasars as Derived from I Zwicky 1 , 2001, astro-ph/0104320.

[22]  Martin J. Rees,et al.  ApJ, in press Preprint typeset using L ATEX style emulateapj v. 04/03/99 MASSIVE BLACK HOLES AS POPULATION III REMNANTS , 2001 .

[23]  Z. Haiman,et al.  What Is the Highest Plausible Redshift of Luminous Quasars? , 2000, astro-ph/0011529.

[24]  Chris L. Fryer,et al.  Pair-Instability Supernovae, Gravity Waves, and Gamma-Ray Transients , 2000, The Astrophysical Journal.

[25]  Ian S. McLean,et al.  Performance and results with the NIRSPEC echelle spectrograph on the Keck II telescope , 2000, Astronomical Telescopes and Instrumentation.

[26]  Paul S. Smith,et al.  Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei , 1999, astro-ph/9911476.

[27]  M. Malkan,et al.  Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. I. Comparing the Photoionization and Reverberation Techniques , 1999, astro-ph/9905224.

[28]  G. Hill,et al.  Lack of Iron Abundance Evolution in High-Redshift QSOs , 1999 .

[29]  G. Ferland,et al.  Elemental Abundances in Quasistellar Objects: Star Formation and Galactic Nuclear Evolution at High Redshifts , 1999, astro-ph/9904223.

[30]  R. Terlevich,et al.  Formation and evolution of elliptical galaxies and QSO activity , 1998, astro-ph/9803283.

[31]  P. Marziani,et al.  Comparative Analysis of the High- and Low-Ionization Lines in the Broad-Line Region of Active Galactic Nuclei , 1996 .

[32]  M. S. Oey,et al.  Atlas of quasar energy distributions , 1994 .

[33]  G. Ferland,et al.  The Chemical Evolution of QSOs and the Implications for Cosmology and Galaxy Formation , 1993 .