A&A 385, L5-L9 (2002)
DOI: 10.1051/0004-6361:20020243
Letter
The first detection of weak gravitational shear in infrared observations: Abell 1689
L. J. King1, 2, D. I. Clowe1, C. Lidman3, P. Schneider1, 2, T. Erben1, 4, 5, J.-P. Kneib6 and G. Meylan71 Institut für Astrophysik und Extraterrestrische Forschung, Auf dem Hügel 71, 53121 Bonn, Germany
2 Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching, Germany
3 European Southern Observatory, Casilla 19, Santiago, Chile
4 Institut d'Astrophysique de Paris, 98 bis Boulevard Arago, 75014 Paris, France
5 Observatoire de Paris, DEMIRM, 61 avenue de l'Observatoire, 75014 Paris, France
6 Observatoire Midi-Pyrénées, 14 Av. E. Belin, 31400 Toulouse, France
7 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
(Received 14 January 2002 / Accepted 13 February 2002)
Abstract
We present the first detection of weak gravitational shear at infrared
wavelengths, using observations of the lensing cluster Abell 1689,
taken with the SofI camera on the ESO-NTT telescope. The imprint of
cluster lenses on the shapes of the background galaxy population has
previously been harnessed at optical wavelengths, and this
gravitational shear signal enables cluster mass distributions to be
probed, independent of whether the matter is luminous or dark. At
near-infrared wavelengths, the spectrophotometric properties of galaxies
facilitate a clean selection of background objects for use in the
lensing analysis. A finite-field mass reconstruction and application
of the aperture mass (
) statistic are presented. The
probability that the peak of the
detection
(
), arises from a chance alignment of background
sources is only ~
. The velocity dispersion of
the best-fit singular isothermal sphere model for the cluster is
, and we
find a
K-band mass-to-light ratio of ~
inside a
radius.
Key words: gravitational lensing -- galaxies: clusters individual: Abell 1689 -- dark matter -- infrared: galaxies
Offprint request: L. J. King, lindsay@astro.uni-bonn.de
SIMBAD Objects in preparation
© ESO 2002
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