Zhou, C;
Tong, A;
Troxel, MA;
Blazek, J;
Lin, C;
Bacon, D;
Bleem, L;
... Wiseman, P; + view all
(2023)
The intrinsic alignment of red galaxies in DES Y1 redMaPPer galaxy clusters.
Monthly Notices of the Royal Astronomical Society
, 526
(1)
pp. 323-336.
10.1093/mnras/stad2712.
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Abstract
Clusters of galaxies trace the most non-linear peaks in the cosmic density field. The weak gravitational lensing of background galaxies by clusters can allow us to infer their masses. However, galaxies associated with the local environment of the cluster can also be intrinsically aligned due to the local tidal gradient, contaminating any cosmology derived from the lensing signal. We measure this intrinsic alignment in Dark Energy Survey (DES) Year 1 REDMAPPER clusters. We find evidence of a non-zero mean radial alignment of galaxies within clusters between redshifts 0.1–0.7. We find a significant systematic in the measured ellipticities of cluster satellite galaxies that we attribute to the central galaxy flux and other intracluster light. We attempt to correct this signal, and fit a simple model for intrinsic alignment amplitude (AIA) to the measurement, finding AIA = 0.15 ± 0.04, when excluding data near the edge of the cluster. We find a significantly stronger alignment of the central galaxy with the cluster dark matter halo at low redshift and with higher richness and central galaxy absolute magnitude (proxies for cluster mass). This is an important demonstration of the ability of large photometric data sets like DES to provide direct constraints on the intrinsic alignment of galaxies within clusters. These measurements can inform improvements to small-scale modelling and simulation of the intrinsic alignment of galaxies to help improve the separation of the intrinsic alignment signal in weak lensing studies.
| Type: | Article |
|---|---|
| Title: | The intrinsic alignment of red galaxies in DES Y1 redMaPPer galaxy clusters |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stad2712 |
| Publisher version: | https://doi.org/10.1093/mnras/stad2712 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | gravitational lensing: weak, galaxies: clusters: general, cosmology: observations |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10179923 |
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