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A fully cosmological model of a Monoceros-like ring

Gómez, FA, White, SDM, Marinacci, F, Slater, CT, Grand, RJJ, Springel, V and Pakmor, R (2015) A fully cosmological model of a Monoceros-like ring. Monthly Notices of the Royal Astronomical Society, 456 (3). pp. 2779-2793. ISSN 0035-8711

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We study the vertical structure of a stellar disc obtained from a fully cosmological highresolution hydrodynamical simulation of the formation of a Milky Way-like galaxy. At the present day, the disc's mean vertical height shows a well defined and strong pattern, with amplitudes as large as 3 kpc in its outer regions. This pattern is the result of a satellite-host halo-disc interaction and reproduces, qualitatively, many of the observable properties of the Monoceros Ring. In particular we find disc material at the distance of Monoceros (R ~ 12-16 kpc, galactocentric) extending far above the mid plane (30°, 〈Z〉 ~ 1-2 kpc) in both hemispheres, as well as well-defined arcs of disc material at heliocentric distances ≤ 5 kpc. The pattern was first excited ≈3 Gyr ago as an m = 1 mode that later winds up into a leading spiral pattern. Interestingly, themain driver behind this perturbation is a low-mass low-velocity fly-by encounter. The satellite has total mass, pericentre distance and pericentric velocity of ~5 per cent of the host, ~80 kpc and 215 km s-1, respectively. The satellite is not massive enough to directly perturb the galactic disc but we show that the density field of the host dark matter halo responds to this interaction resulting in a strong amplification of the perturbative effects. This subsequently causes the onset and development of the Monoceros-like feature.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: 0201 Astronomical and Space Sciences; Astronomy & Astrophysics
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press (OUP)
SWORD Depositor: A Symplectic
Date Deposited: 19 Apr 2023 10:54
Last Modified: 19 Apr 2023 10:54
DOI or ID number: 10.1093/mnras/stv2786
URI: https://researchonline.ljmu.ac.uk/id/eprint/19354
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