Kasliwal, Mansi M. and Massey, Richard and Ellis, Richard S. and Miyazaki, Satoshi and Rhodes, Jason (2008) A comparison of weak-lensing measurements from ground- and space-based facilities. Astrophysical Journal, 684 (1). pp. 34-45. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20090518-105131205
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We assess the relative merits of weak-lensing surveys, using overlapping imaging data from the ground-based Subaru telescope and the Hubble Space Telescope (HST). Our tests complement similar studies undertaken with simulated data. From observations of 230,000 matched objects in the 2 deg^2 COSMOS field, we identify the limit at which faint galaxy shapes can be reliably measured from the ground using well-established shape-measurement techniques. Our ground-based shear catalog achieves subpercent calibration bias compared to high-resolution space-based data for galaxies brighter than i' ≃ 24.5 and with half-light radii larger than 1.8". This selection corresponds to a surface density of 15 galaxies arcmin^(−2) compared to ~71 arcmin^−2 from space. On the other hand, the survey speed of current ground-based facilities is much faster than that of HST, although this gain is mitigated by the increased depth of space-based imaging desirable for tomographic (3D) analyses. As an independent experiment, we also reconstruct the projected mass distribution in the COSMOS field using both data sets, and compare the derived cluster catalogs with those from X-ray observations. The ground-based catalog achieves a reasonable degree of completeness, with minimal contamination and no detected bias, for massive clusters at redshifts 0.2 < z < 0.5. The space-based data provide improved precision and a greater sensitivity to clusters of lower mass or at higher redshift.
|Additional Information:||© 2008 The American Astronomical Society. Received 2007 October 18; accepted 2008 March 5. This work is supported by the US Department of Energy under contract DE-FG02-04ER41316. J. R.’s contribution was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration and funded through the internal Research and Technology Development program. The analysis is based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. It is also based on data collected at the Subaru Telescope, operated by the National Astronomical Observatory of Japan. We acknowledge the careful comments of a referee and also valuable input from Zeljko Ivezik, Alexandre Refregier, James Taylor, and Alexis Finoguenov. We particularly thank Alexie Leauthaud and Takashi Hamana for help with the two galaxy catalogs. We also gratefully acknowledge the contributions of the entire COSMOS collaboration, consisting of more than 70 scientists worldwide. More information on the COSMOS survey is available from http://www.astro.caltech.edu/~cosmos.|
|Subject Keywords:||atmospheric effects; cosmology: observations; gravitational lensing; instrumentation: detectors|
|Official Citation:||A Comparison of Weak-Lensing Measurements from Ground- and Space-Based Facilities Mansi M. Kasliwal, Richard Massey, Richard S. Ellis, Satoshi Miyazaki, and Jason Rhodes 2008 ApJ 684 34-45 doi: 10.1086/588517|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||18 Aug 2009 21:06|
|Last Modified:||26 Dec 2012 11:01|
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