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A&A 482, 403-418 (2008)
DOI: 10.1051/0004-6361:20079119
Realistic simulations of gravitational lensing by galaxy clusters: extracting arc parameters from mock DUNE images
M. Meneghetti1, 2, P. Melchior2, A. Grazian3, G. De Lucia4, K. Dolag4, M. Bartelmann2, C. Heymans5, 6, L. Moscardini7, 8, and M. Radovich91 INAF - Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
e-mail: massimo.meneghetti@oabo.inaf.it
2 ITA, Zentrum für Astronomie, Universität Heidelberg, Albert Überle Str. 2, 69120 Heidelberg, Germany
3 INAF - Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Roma, Italy
4 Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1 85748, Garching bei Muenchen, Germany
5 Department of Physics and Astronomy, The University of British Columbia, 6224 Agricultural Road, Vancouver, V6T 1Z1, Canada
6 Institut d'Astrophysique de Paris, UMR 7095 CNRS, 98bis Bd Arago, 75014 Paris, France
7 Dipartimento di Astronomia, Università di Bologna, via Ranzani 1, 40127 Bologna, Italy
8 INFN-National Institute for Nuclear Physics, Sezione di Bologna, viale Berti Pichat 6/2. 40127 Bologna, Italy
9 INAF - Osservatorio Astronomico di Capodimonte, Salita Moiarello 16, 80131 Napoli, Italy
(Received 21 November 2007 / Accepted 10 January 2008)
Abstract
Aims. We present a newly developed code that allows
simulations of optical observations of galaxy fields with a variety
of instruments. The code incorporates gravitational lensing effects
and is targeted at simulating lensing by galaxy clusters. Our goal
is to create the tools required for comparing theoretical
expectations with observations to better understand
of how observational noise affects lensing applications such as mass
estimates, studies of the internal properties of galaxy clusters and
arc statistics.
Methods. Starting from a set of input parameters,
characterizing both the instruments and the observational
conditions, the simulator provides a virtual observation of a patch
of the sky. It includes several sources of noise such as photon-noise,
sky background, seeing, and instrumental noise. Ray tracing through
simulated mass distributions accounts for gravitational
lensing. Source morphologies are realistically simulated based on
shapelet decompositions of galaxy images retrieved from the
GOODS-ACS archive. According to their morphological class,
spectral-energy-distributions are assigned to the source galaxies to reproduce observations of each galaxy in arbitrary
photometric bands.
Results. We illustrate our techniques showing virtual
observations of a galaxy-cluster core as it would be observed with
the space telescope DUNE, which was recently proposed to ESA within
its "Cosmic vision" program. We analyze the simulated images
using methods applicable to real observations and measure the
properties of gravitational arcs. In particular, we focus on the
determination of their length, width, and curvature radius.
Conclusions. We find
that arc properties strongly depend on several properties of the
sources. In particular, our results show that compact, faint, or low
surface-brightness galaxies that are barely detectable are more
easily distorted as arcs with large length-to-width ratios. We
conclude that realistic lensing simulations can be obtained with the
method proposed here. They will be essential for evaluating and
improving the analysis techniques currently used for cosmological
interpretations of cluster lensing.
Key words: gravitational lensing -- galaxies: clusters: general -- cosmology: observations -- methods: numerical -- submillimeter
© ESO 2008