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Time evolution of intrinsic alignments of galaxies

Schmitz, D. M. and Hirata, C. M. and Blazek, J. and Krause, E. (2018) Time evolution of intrinsic alignments of galaxies. Journal of Cosmology and Astroparticle Physics, 2018 (7). Art. No. 30. ISSN 1475-7516.

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Intrinsic alignments (IA), correlations between the intrinsic shapes and orientations of galaxies on the sky, are both a significant systematic in weak lensing and a probe of the effect of large-scale structure on galactic structure and angular momentum. In the era of precision cosmology, it is thus especially important to model IA with high accuracy. Efforts to use cosmological perturbation theory to model the dependence of IA on the large-scale structure have thus far been relatively successful; however, extant models do not consistently account for time evolution. In particular, advection of galaxies due to peculiar velocities alters the impact of IA, because galaxy positions when observed are generally different from their positions at the epoch when IA is believed to be set. In this work, we evolve the galaxy IA from the time of galaxy formation to the time at which they are observed, including the effects of this advection, and show how this process naturally leads to a dependence of IA on the velocity shear. We calculate the galaxy-galaxy-IA bispectrum to tree level (in the linear matter density) in terms of the evolved IA coefficients. We then discuss the implications for weak lensing systematics as well as for studies of galaxy formation and evolution. We find that considering advection introduces nonlocality into the bispectrum, and that the degree of nonlocality represents the memory of a galaxy's path from the time of its formation to the time of observation. We discuss how this result can be used to constrain the redshift at which IA is determined and provide Fisher estimation for the relevant measurements using the example of SDSS-BOSS.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Schmitz, D. M.0000-0001-6297-9312
Hirata, C. M.0000-0002-2951-4932
Additional Information:© 2018 IOP Publishing Ltd and Sissa Medialab. Received 8 May 2018; Accepted 6 July 2018; Published 16 July 2018. BASS is a key project of the Telescope Access Program (TAP), which has been funded by the National Astronomical Observatories of China, the Chinese Academy of Sciences (the Strategic Priority Research Program “The Emergence of Cosmological Structures” Grant #XDB09000000), and the Special Fund for Astronomy from the Ministry of Finance. The BASS is also supported by the External Cooperation Program of Chinese Academy of Sciences (Grant # 114A11KYSB20160057), and Chinese National Natural Science Foundation (Grant # 11433005). The Legacy Survey team makes use of data products from the Near-Earth Object Widefield Infrared Survey Explorer (NEOWISE), which is a project of the Jet Propulsion Laboratory/California Institute of Technology. NEOWISE is funded by the National Aeronautics and Space Administration. The Legacy Surveys imaging of the DESI footprint is supported by the Director, Office of Science, Office of High Energy Physics of the U.S. Department of Energy under Contract No. DE-AC02-05CH1123, by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility under the same contract; and by the U.S. National Science Foundation, Division of Astronomical Sciences under Contract No. AST-0950945 to NOAO.
Funding AgencyGrant Number
National Astronomical Observatories, Chinese Academy of Sciences (NAOC)UNSPECIFIED
Chinese Academy of SciencesXDB09000000
Ministry of Finance (China)UNSPECIFIED
Chinese Academy of Sciences114A11KYSB20160057
National Natural Science Foundation of China11433005
Department of Energy (DOE)DE-AC02-05CH1123
Subject Keywords:cosmological perturbation theory, weak gravitational lensing, cosmic web, galaxy formation
Issue or Number:7
Record Number:CaltechAUTHORS:20180801-150423286
Persistent URL:
Official Citation:D.M. Schmitz et al JCAP07(2018)030
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:88475
Deposited By: Tony Diaz
Deposited On:01 Aug 2018 22:20
Last Modified:09 Mar 2020 13:19

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