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Dark Energy Survey Year 1 results: constraints on intrinsic alignments and their colour dependence from galaxy clustering and weak lensing

Author(s): Samuroff, S; Blazek, J; Troxel, MA; MacCrann, N; Krause, E; et al

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Abstract: We perform a joint analysis of intrinsic alignments and cosmology using tomographic weak lensing, galaxy clustering, and galaxy-galaxy lensing measurements from Year 1 (Y1) of the Dark Energy Survey. We define early- and late-type subsamples, which are found to pass a series of systematics tests, including for spurious photometric redshift error and point spread function correlations. We analyse these split data alongside the fiducial mixed Y1 sample using a range of intrinsic alignment models. In a fiducial non-linear alignment model analysis, assuming a flat Lambda cold dark matter cosmology, we find a significant difference in intrinsic alignment amplitude, with early-type galaxies favouring A(IA) = 2.38(-0.31)(+0.32) and latetype galaxies consistent with no intrinsic alignments at 0.05(-0.09)(+0.10). The analysis is repeated using a number of extended model spaces, including a physically motivated model that includes both tidal torquing and tidal alignment mechanisms. In multiprobe likelihood chains in which cosmology, intrinsic alignments in both galaxy samples and all other relevant systematics are varied simultaneously, we find the tidal alignment and tidal torquing parts of the intrinsic alignment signal have amplitudes A(1) = 2.66(-0.66)(+0.67), A(2) = -2.94(-1.83)(+1.94), respectively, for earlytype galaxies and A(1) = 0.62(-0.41)(+0.41), A(2) = -2.26(-1.16)(+1.30) for late-type galaxies. In the full (mixed) Y1 sample the best constraints are A(1) = 0.70(-0.38)(+0.41), A(2) = -1.36(-1.41)(+1.08). For all galaxy splits and IA models considered, we report cosmological parameter constraints consistent with the results of the main DES Y1 cosmic shear and multiprobe cosmology papers.
Publication Date: Nov-2019
Electronic Publication Date: 16-Aug-2019
Citation: Samuroff, S, Blazek, J, Troxel, MA, MacCrann, N, Krause, E, Leonard, CD, Prat, J, Gruen, D, Dodelson, S, Eifler, TF, Gatti, M, Hartley, WG, Hoyle, B, Larsen, P, Zuntz, J, Abbott, TMC, Allam, S, Annis, J, Bernstein, GM, Bertin, E, Bridle, SL, Brooks, D, Carnero Rosell, A, Carrasco Kind, M, Carretero, J, Castander, FJ, Cunha, CE, da Costa, LN, Davis, C, De Vicente, J, DePoy, DL, Desai, S, Diehl, HT, Dietrich, JP, Doel, P, Flaugher, B, Fosalba, P, Frieman, J, Garcia-Bellido, J, Gaztanaga, E, Gerdes, DW, Gruendl, RA, Gschwend, J, Gutierrez, G, Hollowood, DL, Honscheid, K, James, DJ, Kuehn, K, Kuropatkin, N, Lima, M, Maia, MAG, March, M, Marshall, JL, Martini, P, Melchior, P, Menanteau, F, Miller, CJ, Miquel, R, Ogando, RLC, Plazas, AA, Sanchez, E, Scarpine, V, Schindler, R, Schubnell, M, Serrano, S, Sevilla-Noarbe, I, Sheldon, E, Smith, M, Sobreira, F, Suchyta, E, Tarle, G, Thomas, D, Vikram, V, Collaboration, DES. (2019). Dark Energy Survey Year 1 results: constraints on intrinsic alignments and their colour dependence from galaxy clustering and weak lensing. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 489 (5453 - 5482. doi:10.1093/mnras/stz2197
DOI: doi:10.1093/mnras/stz2197
ISSN: 0035-8711
EISSN: 1365-2966
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Pages: 5453 - 5482
Type of Material: Journal Article
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.

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