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The imprint of dark subhaloes on the circumgalactic medium

McCarthy, IG and Font, AS The imprint of dark subhaloes on the circumgalactic medium. Monthly Notices of the Royal Astronomical Society. ISSN 0035-8711 (Accepted)

The imprint of dark subhaloes on the circumgalactic medium.pdf - Accepted Version

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The standard model of cosmology, the LCDM model, robustly predicts the existence of a multitude of dark matter 'subhaloes' around galaxies like the Milky Way. A wide variety of observations have been proposed to look for the gravitational effects such subhaloes would induce in observable matter. Most of these approaches pertain to the stellar or cool gaseous phases of matter. Here we propose a new approach, which is to search for the perturbations that such dark subhaloes would source in the warm/hot circumgalactic medium (CGM) around normal galaxies. With a combination of analytic theory, carefully-controlled high-resolution idealised simulations, and full cosmological hydrodynamical simulations, we calculate the expected signal and how it depends on important physical parameters (subhalo mass, CGM temperature, and relative velocity). We find that dark subhaloes enhance the local CGM pressure, density, and temperature, in order of decreasing magnitude of the effect. For the pressure, the fluctuations can vary in magnitude from tens of percent (for subhaloes with M_sub=10^10 Msun) to a few percent (for subhaloes with M_sub=10^8 Msun), although this depends strongly on the CGM temperature. The subhaloes also induce fluctuations in the velocity field ranging in magnitude from a few km/s up to 25 km/s. We propose that X-ray, Sunyaev-Zel'dovich effect, radio dispersion measure, and quasar absorption line observations can be used to measure these fluctuations and place constraints on the abundance and distribution of dark subhaloes, thereby placing constraints on the nature of dark matter.

Item Type: Article
Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record [insert complete citation information here] is available online at: xxxxxxx [insert URL that the author will receive upon publication here].
Uncontrolled Keywords: astro-ph.CO; astro-ph.CO; astro-ph.GA
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 09 Sep 2020 08:25
Last Modified: 09 Sep 2020 08:30
URI: https://researchonline.ljmu.ac.uk/id/eprint/13602

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