---
OA_place: repository
OA_type: green
_id: '18738'
abstract:
- lang: eng
  text: Gravitational lensing can amplify the apparent brightness of distant sources.
    Images that are highly magnified are often part of multiply imaged systems, but
    we consider the possibility of having large magnifications without additional
    detectable images. In rare but nonnegligible situations, lensing can produce a
    single highly magnified image; this phenomenon is mainly associated with massive
    cluster-scale halos (≳1013.5 M☉). Alternatively, lensing can produce multiply
    imaged systems in which the extra images are either unresolved or too faint to
    be detectable. This phenomenon is dominated by galaxies and lower mass halos (≲1012
    M☉) and is very sensitive to the inner density profile of the halos. Although
    we study the general problem, we customize our calculations to four quasars at
    redshift z ≈ 6 in the Sloan Digital Sky Survey (SDSS), for which Richards et al.
    (2004) have ruled out the presence of extra images down to an image splitting
    of Δθ = 0farcs3 and a flux ratio of f = 0.01. We predict that 9%-29% of all z
    ≈ 6 quasars that are magnified by a factor of μ > 10 would lack detectable extra
    images, with 5%-10% being true singly imaged systems. The maximum of 29% is reached
    only in the unlikely event that all low-mass (≲1010 M☉) halos have highly concentrated
    (isothermal) profiles. In more realistic models in which dwarf halos have flatter
    (Navarro-Frenk-White) inner profiles, the maximum probability is ~10%. We conclude
    that the probability that all four SDSS quasars are magnified by a factor of 10
    is ≲10-4. The only escape from this conclusion is if there are many (>10) multiply
    imaged z ≈ 6 quasars in the SDSS database that have not yet been identified, which
    seems unlikely. In other words, lensing cannot explain the brightnesses of the
    z ≈ 6 quasars, and models that invoke lensing to avoid having billion-solar-mass
    black holes in the young universe are not viable.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Charles R.
  full_name: Keeton, Charles R.
  last_name: Keeton
- first_name: Michael
  full_name: Kuhlen, Michael
  last_name: Kuhlen
- first_name: Zoltán
  full_name: Haiman, Zoltán
  id: 7c006e8c-cc0d-11ee-8322-cb904ef76f36
  last_name: Haiman
  orcid: 0000-0003-3633-5403
citation:
  ama: Keeton CR, Kuhlen M, Haiman Z. Gravitational lensing magnification without
    multiple imaging. <i>The Astrophysical Journal</i>. 2005;621(2):559-573. doi:<a
    href="https://doi.org/10.1086/427722">10.1086/427722</a>
  apa: Keeton, C. R., Kuhlen, M., &#38; Haiman, Z. (2005). Gravitational lensing magnification
    without multiple imaging. <i>The Astrophysical Journal</i>. American Astronomical
    Society. <a href="https://doi.org/10.1086/427722">https://doi.org/10.1086/427722</a>
  chicago: Keeton, Charles R., Michael Kuhlen, and Zoltán Haiman. “Gravitational Lensing
    Magnification without Multiple Imaging.” <i>The Astrophysical Journal</i>. American
    Astronomical Society, 2005. <a href="https://doi.org/10.1086/427722">https://doi.org/10.1086/427722</a>.
  ieee: C. R. Keeton, M. Kuhlen, and Z. Haiman, “Gravitational lensing magnification
    without multiple imaging,” <i>The Astrophysical Journal</i>, vol. 621, no. 2.
    American Astronomical Society, pp. 559–573, 2005.
  ista: Keeton CR, Kuhlen M, Haiman Z. 2005. Gravitational lensing magnification without
    multiple imaging. The Astrophysical Journal. 621(2), 559–573.
  mla: Keeton, Charles R., et al. “Gravitational Lensing Magnification without Multiple
    Imaging.” <i>The Astrophysical Journal</i>, vol. 621, no. 2, American Astronomical
    Society, 2005, pp. 559–73, doi:<a href="https://doi.org/10.1086/427722">10.1086/427722</a>.
  short: C.R. Keeton, M. Kuhlen, Z. Haiman, The Astrophysical Journal 621 (2005) 559–573.
date_created: 2025-01-03T12:32:53Z
date_published: 2005-03-10T00:00:00Z
date_updated: 2025-01-07T13:05:57Z
day: '10'
doi: 10.1086/427722
extern: '1'
external_id:
  arxiv:
  - astro-ph/0405143
intvolume: '       621'
issue: '2'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/astro-ph/0405143
month: '03'
oa: 1
oa_version: Preprint
page: 559-573
publication: The Astrophysical Journal
publication_identifier:
  eissn:
  - 1538-4357
  issn:
  - 0004-637X
publication_status: published
publisher: American Astronomical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Gravitational lensing magnification without multiple imaging
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 621
year: '2005'
...