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Environment from cross-correlations: connecting hot gas and the quenching of galaxies

Kukstas, E, McCarthy, IG, Baldry, IK and Font, AS (2020) Environment from cross-correlations: connecting hot gas and the quenching of galaxies. Monthly Notices of the Royal Astronomical Society, 496 (2). pp. 2241-2261. ISSN 0035-8711

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The observable properties of galaxies are known to depend on both internal processes and the external environment. In terms of the environmental role, we still do not have a clear picture of the processes driving the transformation of galaxies. This may be due to the fact that these environmental processes depend on local physical conditions (e.g., local tidal force or hot gas density), whereas observations typically probe only broad-brush proxies for these conditions (e.g., host halo mass, distance to the N^th nearest neighbour, etc.). Here we propose a new method that directly links galaxies to their local environments, by using spatial cross-correlations of galaxy catalogues with maps from large-scale structure surveys (e.g., thermal Sunyaev-Zel'dovich [tSZ] effect, diffuse X-ray emission, weak lensing of galaxies or the CMB). We focus here on the quenching of galaxies and its link to local hot gas properties. Maps of galaxy overdensity and quenched fraction excess are constructed from volume-limited SDSS catalogs, which are cross-correlated with maps of tSZ effect from Planck and X-ray emission from ROSAT. Strong signals out to Mpc scales are detected for all cross-correlations and are compared to predictions from cosmological hydrodynamical simulations (the EAGLE and BAHAMAS simulations). The simulations successfully reproduce many, but not all, of the observed power spectra, with an indication that environmental quenching may be too efficient in the simulations. We demonstrate that the cross-correlations are sensitive to both the internal and external processes responsible for quenching. The methods outlined in this paper can be easily adapted to other observables and, with upcoming surveys, will provide a stringent direct test of physical models for environmental transformation.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2020 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: astro-ph.GA; astro-ph.GA; astro-ph.CO
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 02 Jun 2020 11:08
Last Modified: 04 Sep 2021 09:07
URI: https://researchonline.ljmu.ac.uk/id/eprint/11070
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