---
_id: '17723'
abstract:
- lang: eng
  text: "The recent discovery of bright quasars around redshift z=6 suggests that
    black holes (BHs) with masses in excess of 10^9 Msun have already assembled at
    a very early stage in the evolution of the universe. An alternative interpretation
    is that these quasars are powered by less massive BHs, but their fluxes are strongly
    magnified through gravitational lensing by intervening galaxies. Here we analyze
    the flux distribution of the Ly alpha emission of the quasar with the highest
    known redshift, SDSS 1030+0524, at z=6.28. We show that this object could not
    have been magnified by lensing by more than a factor of five. The constraint arises
    from the large observed size, 30 (comoving) Mpc, of the ionized region around
    this quasar, and relies crucially only on the assumption that the quasar is embedded
    in a largely neutral IGM. Based on the line/continuum ratio of SDSS 1030+0524,
    we argue further that this quasar also cannot be beamed by a significant factor.
    We conclude that the minimum mass for its resident BH is 4 x 10^8 Msun (for magnification
    by a factor of five); if the mass is this low, then the quasars had to switch
    on prior to redshift z=9.\r\nFrom the size of the ionized region, we are also
    able to place an absolute lower bound on the age of this quasar at t > 2 x 10^7
    years."
article_processing_charge: No
article_type: original
author:
- first_name: Zoltán
  full_name: Haiman, Zoltán
  id: 7c006e8c-cc0d-11ee-8322-cb904ef76f36
  last_name: Haiman
- first_name: Renyue
  full_name: Cen, Renyue
  last_name: Cen
citation:
  ama: Haiman Z, Cen R. A constraint on the gravitational lensing magnification and
    age of the redshift z = 6.28 Quasar SDSS 1030+0524. <i>The Astrophysical Journal</i>.
    2002;578(2):702-707. doi:<a href="https://doi.org/10.1086/342610">10.1086/342610</a>
  apa: Haiman, Z., &#38; Cen, R. (2002). A constraint on the gravitational lensing
    magnification and age of the redshift z = 6.28 Quasar SDSS 1030+0524. <i>The Astrophysical
    Journal</i>. American Astronomical Society. <a href="https://doi.org/10.1086/342610">https://doi.org/10.1086/342610</a>
  chicago: Haiman, Zoltán, and Renyue Cen. “A Constraint on the Gravitational Lensing
    Magnification and Age of the Redshift z = 6.28 Quasar SDSS 1030+0524.” <i>The
    Astrophysical Journal</i>. American Astronomical Society, 2002. <a href="https://doi.org/10.1086/342610">https://doi.org/10.1086/342610</a>.
  ieee: Z. Haiman and R. Cen, “A constraint on the gravitational lensing magnification
    and age of the redshift z = 6.28 Quasar SDSS 1030+0524,” <i>The Astrophysical
    Journal</i>, vol. 578, no. 2. American Astronomical Society, pp. 702–707, 2002.
  ista: Haiman Z, Cen R. 2002. A constraint on the gravitational lensing magnification
    and age of the redshift z = 6.28 Quasar SDSS 1030+0524. The Astrophysical Journal.
    578(2), 702–707.
  mla: Haiman, Zoltán, and Renyue Cen. “A Constraint on the Gravitational Lensing
    Magnification and Age of the Redshift z = 6.28 Quasar SDSS 1030+0524.” <i>The
    Astrophysical Journal</i>, vol. 578, no. 2, American Astronomical Society, 2002,
    pp. 702–07, doi:<a href="https://doi.org/10.1086/342610">10.1086/342610</a>.
  short: Z. Haiman, R. Cen, The Astrophysical Journal 578 (2002) 702–707.
date_created: 2024-09-06T09:11:03Z
date_published: 2002-10-20T00:00:00Z
date_updated: 2024-09-25T14:06:28Z
day: '20'
doi: 10.1086/342610
extern: '1'
intvolume: '       578'
issue: '2'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1086/342610
month: '10'
oa: 1
oa_version: Published Version
page: 702-707
publication: The Astrophysical Journal
publication_identifier:
  issn:
  - 0004-637X
  - 1538-4357
publication_status: published
publisher: American Astronomical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: A constraint on the gravitational lensing magnification and age of the redshift
  z = 6.28 Quasar SDSS 1030+0524
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 578
year: '2002'
...