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Image Analysis for Cosmology: Results from the GREAT10 Star Challenge

Kitching, T. D. and Rowe, B. and Gill, M. and Heymans, C. and Massey, R. and Witherick, D. and Courbin, F. and Georgatzis, K. and Gentile, M. and Gruen, D. and Kilbinger, M. and Li, G. L. and Mariglis, A. P. and Meylan, G. and Storkey, A. and Xin, B. (2013) Image Analysis for Cosmology: Results from the GREAT10 Star Challenge. Astrophysical Journal Supplement Series, 205 (2). Art. No. 12. ISSN 0067-0049. doi:10.1088/0067-0049/205/2/12.

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We present the results from the first public blind point-spread function (PSF) reconstruction challenge, the GRavitational lEnsing Accuracy Testing 2010 (GREAT10) Star Challenge. Reconstruction of a spatially varying PSF, sparsely sampled by stars, at non-star positions is a critical part in the image analysis for weak lensing where inaccuracies in the modeled ellipticity e and size R^2 can impact the ability to measure the shapes of galaxies. This is of importance because weak lensing is a particularly sensitive probe of dark energy and can be used to map the mass distribution of large scale structure. Participants in the challenge were presented with 27,500 stars over 1300 images subdivided into 26 sets, where in each set a category change was made in the type or spatial variation of the PSF. Thirty submissions were made by nine teams. The best methods reconstructed the PSF with an accuracy of σ(e) ≈ 2.5 × 10^(–4) and σ(R^2)/R^2 ≈ 7.4 × 10^(–4). For a fixed pixel scale, narrower PSFs were found to be more difficult to model than larger PSFs, and the PSF reconstruction was severely degraded with the inclusion of an atmospheric turbulence model (although this result is likely to be a strong function of the amplitude of the turbulence power spectrum).

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Gruen, D.0000-0003-3270-7644
Additional Information:© 2013 American Astronomical Society. Received 2012 October 6; accepted 2013 February 6; published 2013 March 5. T.D.K. is supported by a Royal Society University Research Fellowship, and was supported by a Royal Astronomical Society 2010 Fellowship and the University of Edinburgh for some of this work. B.R. and C.H. acknowledge support from the European Research Council in the form of a Starting Grant with numbers 24067 (B.R.) and 240185 (C.H.). R.M. is supported by a Royal Society University Research Fellowship. D.G. was supported by SFB-Transregio 33 “The Dark Universe” by the Deutsche Forschungsgemeinschaft (DFG) and the DFG cluster of excellence “Origin and Structure of the Universe” and thanks Gary Bernstein and Stella Seitz for helpful discussions. M.Ge., G.C., and G.M. are supported by the Swiss National Science Foundation (SNSF). G.L. thanks Wei Cui for useful discussions. G.L. and B.X. were supported in part by the U.S. Department of Energy through Grant DE-FG02-91ER4068 and G.L. is also supported by the one-hundred talents program of the Chinese Academy of Sciences (CAS). M.K. thanks Liping Fu. This work was funded by a EU FP7 PASCAL 2 Challenge Grant. Workshops for the GREAT10 Challenge were funded by the eScience STFC Theme and by NASA JPL, and hosted at the eScience Institute Edinburgh and by IPAC Caltech, Pasadena. We thank Francesca Ziolkowska, Harry Teplitz, and Helene Seibly for local organization of the workshops. We thank the GREAT10 Advisory team, co-authors of the GREAT10 handbook (Kitching et al. 2012a), for discussions before and after the challenge. Contributions: All authors contributed to the writing and analysis presented. T.D.K. was PI of GREAT10, defined and created the simulations, and lead the analysis. T.D.K., B.R., M.G., C.H., R.M. were active members of the GREAT10 team during 2010 December to 2011 September and after the challenge. B.R. created the FITS image simulation code. M.Ge., F.C., G.M., D.G.,M.K., K.G., A.S., A.M., G.L., B.X. submitted entries to the GREAT10 Star Challenge. D.W. maintained the GREAT10 leaderboard and processed submissions with T.D.K. during the challenge.
Funding AgencyGrant Number
Royal Astronomical SocietyUNSPECIFIED
University of EdinburghUNSPECIFIED
European Research Council (ERC)240672
European Research Council (ERC)240185
Deutsche Forschungsgemeinschaft (DFG)SFB-Transregio 33
Swiss National Science Foundation (SNSF)UNSPECIFIED
Department of Energy (DOE)DE-FG02-91ER4068
Chinese Academy of SciencesUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Subject Keywords:atmospheric effects; cosmology: observations; methods: data analysis; techniques: image processing
Issue or Number:2
Record Number:CaltechAUTHORS:20130510-072703209
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Official Citation:Image Analysis for Cosmology: Results from the GREAT10 Star Challenge T. D. Kitching et al. 2013 ApJS 205 12
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:38406
Deposited By: Ruth Sustaita
Deposited On:10 May 2013 15:35
Last Modified:09 Nov 2021 23:37

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