Galaxy bias from the Dark Energy Survey Science Verification data: combining galaxy density maps and weak lensing maps

Chang, C, Pujol, A, Gaztañaga, E, Amara, A, Réfrégier, A, Bacon, D, Becker, M R, Bonnett, C, Carretero, J, Castander, F J, Crocce, M, Fosalba, P, Giannantonio, T, Hartley, W, Jarvis, M, Kacprzak, T, Ross, A J, Sheldon, E, Troxel, M A, Vikram, V, Zuntz, J, Abbott, T M C, Abdalla, F B, Allam, S, Annis, J, Benoit-Lévy, A, Bertin, E, Brooks, D, Buckley-Geer, E, Burke, D L, Capozzi, D, Carnero Rosell, A, Carrasco Kind, M, Cunha, C E, D'Andrea, C B, da Costa, L N, Desai, S, Diehl, H T, Dietrich, J P, Doel, P, Eifler, T F, Estrada, J, Evrard, A E, Flaugher, B, Frieman, J, Goldstein, D A, Gruen, D, Gruendl, R A, Gutierrez, G, Honscheid, K, Jain, B, James, D J, Kuehn, K, Kuropatkin, N, Lahav, O, Li, T S, Lima, M, Marshall, J L, Martini, P, Melchior, P, Miller, C J, Miquel, R, Mohr, J J, Nichol, R C, Nord, B, Ogando, R, Plazas, A A, Reil, K, Romer, K, Roodman, A, Rykoff, E S, Sanchez, E, Scarpine, V, Schubnell, M, Sevilla-Noarbe, I, Smith, R C, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, M E C, Tarle, G, Thomas, D and Walker, A R (2016) Galaxy bias from the Dark Energy Survey Science Verification data: combining galaxy density maps and weak lensing maps. Monthly Notices of the Royal Astronomical Society, 459 (3). pp. 3203-3216. ISSN 0035-8711

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We measure the redshift evolution of galaxy bias for a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a ˜116 deg2 area of the Dark Energy Survey (DES) Science Verification (SV) data. This method was first developed in Amara et al. and later re-examined in a companion paper with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a i < 22.5 galaxy sample. We find the galaxy bias and 1sigma error bars in four photometric redshift bins to be 1.12 ± 0.19 (z = 0.2-0.4), 0.97 ± 0.15 (z = 0.4-0.6), 1.38 ± 0.39 (z = 0.6-0.8), and 1.45 ± 0.56 (z = 0.8-1.0). These measurements are consistent at the 2sigma level with measurements on the same data set using galaxy clustering and cross-correlation of galaxies with cosmic microwave background lensing, with most of the redshift bins consistent within the 1sigma error bars. In addition, our method provides the only sigma8 independent constraint among the three. We forward model the main observational effects using mock galaxy catalogues by including shape noise, photo-z errors, and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Furthermore, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.

Item Type: Article
Keywords: Gravitational lensing: weak, Surveys, Large-scale structure of Universe
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
Depositing User: Richard Chambers
Date Deposited: 23 Jun 2016 14:27
Last Modified: 16 Mar 2017 18:00

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Project NameSussex Project NumberFunderFunder Ref
Astrophysics and Cosmology - Sussex Consolidated GrantG1291STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/L000652/1