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Main Authors: Zhou, Yufan Fane, Li, Zhiyuan, Li, Hui
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.05745
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author Zhou, Yufan Fane
Li, Zhiyuan
Li, Hui
author_facet Zhou, Yufan Fane
Li, Zhiyuan
Li, Hui
contents Bars, a common and important structure in disk galaxies, can be induced by galaxy interactions. Although there have been some studies on bar formation in flybys or collisions, the vast parameter space still leaves many scenarios that require further investigation. Here, we focus on the role of collisions caused by small galaxies (denoted as intruders), referred to as satellite collisions, in bar formation for MW/M31-like galaxies (denoted as target galaxies). Multiple sets of simulations with varying intruder initial velocities, inclination angles, collision positions, and intruder masses were run to study the dependence of this mechanism on these parameters. Our simulations show that bar formation favors moderate collision velocity, large inclination angle, off-center collision position, and large intruder mass. However, the bar's pattern speed and length are insensitive to these parameters, as the intruder's mass is relatively small compared to that of the target galaxy itself. Moreover, based on our tests, the intruder mass should be more than $\sim 3\times10^{9}$ ${\rm M}_{\odot}$ in order for this bar formation mechanism to operate effectively in MW/M31-like galaxies. Our work suggests the possibility that satellite collisions may have contributed, to some extent, to the bar formation in the Milky Way or M31.
format Preprint
id arxiv_https___arxiv_org_abs_2507_05745
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle N-body simulations of galaxy bars generated by satellite collisions: effects of the impact geometry
Zhou, Yufan Fane
Li, Zhiyuan
Li, Hui
Astrophysics of Galaxies
Bars, a common and important structure in disk galaxies, can be induced by galaxy interactions. Although there have been some studies on bar formation in flybys or collisions, the vast parameter space still leaves many scenarios that require further investigation. Here, we focus on the role of collisions caused by small galaxies (denoted as intruders), referred to as satellite collisions, in bar formation for MW/M31-like galaxies (denoted as target galaxies). Multiple sets of simulations with varying intruder initial velocities, inclination angles, collision positions, and intruder masses were run to study the dependence of this mechanism on these parameters. Our simulations show that bar formation favors moderate collision velocity, large inclination angle, off-center collision position, and large intruder mass. However, the bar's pattern speed and length are insensitive to these parameters, as the intruder's mass is relatively small compared to that of the target galaxy itself. Moreover, based on our tests, the intruder mass should be more than $\sim 3\times10^{9}$ ${\rm M}_{\odot}$ in order for this bar formation mechanism to operate effectively in MW/M31-like galaxies. Our work suggests the possibility that satellite collisions may have contributed, to some extent, to the bar formation in the Milky Way or M31.
title N-body simulations of galaxy bars generated by satellite collisions: effects of the impact geometry
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2507.05745