Wide-Field Lensing Mass Maps from DES Science Verification Data: Methodology and Detailed Analysis
Abstract
Weak gravitational lensing allows one to reconstruct the spatial distribution of the projected mass density across the sky. These "mass maps" provide a powerful tool for studying cosmology as they probe both luminous and dark matter. In this paper, we present a weak lensing mass map reconstructed from shear measurements in a 139 sq. deg area from the Dark Energy Survey (DES) Science Verification (SV) data. We compare the distribution of mass with that of the foreground distribution of galaxies and clusters. The overdensities in the reconstructed map correlate well with the distribution of optically detected clusters. We demonstrate that candidate superclusters and voids along the line of sight can be identified, exploiting the tight scatter of the cluster photometric redshifts. We cross-correlate the mass map with a foreground magnitude-limited galaxy sample from the same data. Our measurement gives results consistent with mock catalogs from N-body simulations that include the primary sources of statistical uncertainties in the galaxy, lensing, and photo-z catalogs. The statistical significance of the cross-correlation is at the 6.8-sigma level with 20 arcminute smoothing. A major goal of this study is to investigate systematic effects arising from a variety of sources, including PSF and photo-z uncertainties. We make maps derived from twenty variables that may characterize systematics and find the principal components. We find that the contribution of systematics to the lensing mass maps is generally within measurement uncertainties. In this work, we analyze less than 3% of the final area that will be mapped by the DES; the tools and analysis techniques developed in this paper can be applied to forthcoming larger datasets from the survey.
Cite
@article{arxiv.1504.03002,
title = {Wide-Field Lensing Mass Maps from DES Science Verification Data: Methodology and Detailed Analysis},
author = {V. Vikram and C. Chang and B. Jain and D. Bacon and A. Amara and M. R. Becker and G. Bernstein and C. Bonnett and S. Bridle and D. Brout and M. Busha and J. Frieman and E. Gaztanaga and W. Hartley and M. Jarvis and T. Kacprzak and A. Kovacs and O. Lahav and B. Leistedt and H. Lin and P. Melchior and H. Peiris and E. Rozo and E. Rykoff and C. Sanchez and E. Sheldon and M. A. Troxel and R. Wechsler and J. Zuntz and T. Abbott and F. B. Abdalla and R. Armstrong and M. Banerji and A. H. Bauer and A. Benoit-Levy and E. Bertin and D. Brooks and E. Buckley-Geer and D. L. Burke and D. Capozzi and A. Carnero Rosell and M. Carrasco Kind and F. J. Castander and M. Crocce and C. E. Cunha and C. B. D'Andrea and L. N. da Costa and D. L. DePoy and S. Desai and H. T. Diehl and J. P. Dietrich and J. Estrada and A. E. Evrard and A. Fausti Neto and E. Fernandez and B. Flaugher and P. Fosalba and D. Gerdes and D. Gruen and R. A. Gruendl and K. Honscheid and D. James and S. Kent and K. Kuehn and N. Kuropatkin and T. S. Li and M. A. G. Maia and M. Makler and M. March and J. Marshall and P. Martini and K. W. Merritt and C. J. Miller and R. Miquel and E. Neilsen and R. C. Nichol and B. Nord and R. Ogando and A. A. Plazas and A. K. Romer and A. Roodman and E. Sanchez and V. Scarpine and I. Sevilla and R. C. Smith and M. Soares-Santos and F. Sobreira and E. Suchyta and M. E. C. Swanson and G. Tarle and J. Thaler and D. Thomas and A. R. Walker and J. Weller},
journal= {arXiv preprint arXiv:1504.03002},
year = {2015}
}
Comments
21 pages, 14 figures, 2 tables; accepted to PRD