How the cosmic web induces intrinsic alignments of galaxies
Intrinsic alignments are believed to be a major source of systematics for future generation of weak gravitational lensing surveys like Euclid or LSST. Direct measurements of the alignment of the projected light distribution of galaxies in wide field imaging data seem to agree on a contamination at...
| Main Authors: | , , , , |
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| Format: | Journal article |
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Cambridge University Press
2016
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| _version_ | 1826284743126155264 |
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| author | Codis, S Dubois, Y Pichon, C Devriendt, J Slyz, A |
| author_facet | Codis, S Dubois, Y Pichon, C Devriendt, J Slyz, A |
| author_sort | Codis, S |
| collection | OXFORD |
| description | Intrinsic alignments are believed to be a major source of systematics for future generation of weak gravitational lensing surveys like Euclid or LSST. Direct measurements of the alignment of the projected light distribution of galaxies in wide field imaging data seem to agree on a contamination at a level of a few per cent of the shear correlation functions, although the amplitude of the effect depends on the population of galaxies considered. Given this dependency, it is difficult to use dark matter-only simulations as the sole resource to predict and control intrinsic alignments. We report here estimates on the level of intrinsic alignment in the cosmological hydrodynamical simulation Horizon-AGN that could be a major source of systematic errors in weak gravitational lensing measurements. In particular, assuming that the spin of galaxies is a good proxy for their ellipticity, we show how those spins are spatially correlated and how they couple to the tidal field in which they are embedded. We also present theoretical calculations that illustrate and qualitatively explain the observed signals. |
| first_indexed | 2024-03-07T01:18:25Z |
| format | Journal article |
| id | oxford-uuid:8f7fb65b-f857-4a20-9b19-293021463596 |
| institution | University of Oxford |
| last_indexed | 2024-03-07T01:18:25Z |
| publishDate | 2016 |
| publisher | Cambridge University Press |
| record_format | dspace |
| spelling | oxford-uuid:8f7fb65b-f857-4a20-9b19-2930214635962022-03-26T23:04:48ZHow the cosmic web induces intrinsic alignments of galaxiesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:8f7fb65b-f857-4a20-9b19-293021463596Symplectic Elements at OxfordCambridge University Press2016Codis, SDubois, YPichon, CDevriendt, JSlyz, A Intrinsic alignments are believed to be a major source of systematics for future generation of weak gravitational lensing surveys like Euclid or LSST. Direct measurements of the alignment of the projected light distribution of galaxies in wide field imaging data seem to agree on a contamination at a level of a few per cent of the shear correlation functions, although the amplitude of the effect depends on the population of galaxies considered. Given this dependency, it is difficult to use dark matter-only simulations as the sole resource to predict and control intrinsic alignments. We report here estimates on the level of intrinsic alignment in the cosmological hydrodynamical simulation Horizon-AGN that could be a major source of systematic errors in weak gravitational lensing measurements. In particular, assuming that the spin of galaxies is a good proxy for their ellipticity, we show how those spins are spatially correlated and how they couple to the tidal field in which they are embedded. We also present theoretical calculations that illustrate and qualitatively explain the observed signals. |
| spellingShingle | Codis, S Dubois, Y Pichon, C Devriendt, J Slyz, A How the cosmic web induces intrinsic alignments of galaxies |
| title | How the cosmic web induces intrinsic alignments of galaxies |
| title_full | How the cosmic web induces intrinsic alignments of galaxies |
| title_fullStr | How the cosmic web induces intrinsic alignments of galaxies |
| title_full_unstemmed | How the cosmic web induces intrinsic alignments of galaxies |
| title_short | How the cosmic web induces intrinsic alignments of galaxies |
| title_sort | how the cosmic web induces intrinsic alignments of galaxies |
| work_keys_str_mv | AT codiss howthecosmicwebinducesintrinsicalignmentsofgalaxies AT duboisy howthecosmicwebinducesintrinsicalignmentsofgalaxies AT pichonc howthecosmicwebinducesintrinsicalignmentsofgalaxies AT devriendtj howthecosmicwebinducesintrinsicalignmentsofgalaxies AT slyza howthecosmicwebinducesintrinsicalignmentsofgalaxies |