A gravitationally lensed quasar with quadruple images separated by 14.62 arcseconds.
Gravitational lensing is a powerful tool for the study of the distribution of dark matter in the Universe. The cold-dark-matter model of the formation of large-scale structures (that is, clusters of galaxies and even larger assemblies) predicts the existence of quasars gravitationally lensed by concentrations of dark matter so massive that the quasar images would be split by over 7 arcsec. Numerous searches for large-separation lensed quasars have, however, been unsuccessful. All of the roughly 70 lensed quasars known, including the first lensed quasar discovered, have smaller separations that can be explained in terms of galaxy-scale concentrations of baryonic matter. Although gravitationally lensed galaxies with large separations are known, quasars are more useful cosmological probes because of the simplicity of the resulting lens systems. Here we report the discovery of a lensed quasar, SDSS J1004 + 4112, which has a maximum separation between the components of 14.62 arcsec. Such a large separation means that the lensing object must be dominated by dark matter. Our results are fully consistent with theoretical expectations based on the cold-dark-matter model.
Inada
Naohisa
N
Department of Physics, School of Science, The University of Tokyo, 113-0033, Japan. inada@utap.phys.s.u-tokyo.ac.jp
Oguri
Masamune
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Pindor
Bartosz
B
Hennawi
Joseph F
JF
Chiu
Kuenley
K
Zheng
Wei
W
Ichikawa
Shin-Ichi
S
Gregg
Michael D
MD
Becker
Robert H
RH
Suto
Yasushi
Y
Strauss
Michael A
MA
Turner
Edwin L
EL
Keeton
Charles R
CR
Annis
James
J
Castander
Francisco J
FJ
Eisenstein
Daniel J
DJ
Frieman
Joshua A
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Fukugita
Masataka
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Gunn
James E
JE
Johnston
David E
DE
Kent
Stephen M
SM
Nichol
Robert C
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Richards
Gordon T
GT
Rix
Hans-Walter
HW
Sheldon
Erin Scott
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Bahcall
Neta A
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Brinkmann
J
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Ivezić
Zeljko
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Lamb
Don Q
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McKay
Timothy A
TA
Schneider
Donald P
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York
Donald G
DG