The Role of Inner Halo Angular Momentum (Spin) in Shaping Dark Matter Bars in Milky Way Analogs

Fuente: arXiv
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Main Authors: Ghosh, Shouvik, Kataria, Sandeep Kumar
Format: Preprint
Published: 2026
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author Ghosh, Shouvik
Kataria, Sandeep Kumar
author_facet Ghosh, Shouvik
Kataria, Sandeep Kumar
contents Studies of galactic bars have primarily focused on stellar bars, since they can be directly observed through ultraviolet to infrared wavebands. Cosmological as well as idealised simulations reveal that the dark matter (DM) haloes interact with baryonic matter, primarily the stellar bars, dynamically by means of the exchange of angular momentum. In these simulations, the spherical DM halo dynamically responds to interaction with the stellar bar by reshaping its orbital structure in the proximity of the stellar bar, forming a bar-like configuration, called as the Dark Matter (DM) bar. Using N-body simulations of Milky Way analogs we discuss the role of inner halo angular momentum, measured as halo spin parameter λ of the dark matter halo, on formation and evolutionary characteristics of the DM bars. Our systematic study involves haloes with initial spin configurations ranging from λ = 0 to 0.1. The result conveys that DM bar formation and its characteristics are extensively dependent on the initial spin parameter λ of the DM halo. We demonstrate that the strength of the dark matter bar gradually increases with an increase in halo spin in long-term evolution, with a significant impact of stellar bar buckling on dark matter bar strength. The evolutionary characteristics of the DM bar are strongly influenced by the initial spin of the host halo.
format Preprint
id arxiv_https___arxiv_org_abs_2601_14420
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The Role of Inner Halo Angular Momentum (Spin) in Shaping Dark Matter Bars in Milky Way Analogs
Ghosh, Shouvik
Kataria, Sandeep Kumar
Astrophysics of Galaxies
Studies of galactic bars have primarily focused on stellar bars, since they can be directly observed through ultraviolet to infrared wavebands. Cosmological as well as idealised simulations reveal that the dark matter (DM) haloes interact with baryonic matter, primarily the stellar bars, dynamically by means of the exchange of angular momentum. In these simulations, the spherical DM halo dynamically responds to interaction with the stellar bar by reshaping its orbital structure in the proximity of the stellar bar, forming a bar-like configuration, called as the Dark Matter (DM) bar. Using N-body simulations of Milky Way analogs we discuss the role of inner halo angular momentum, measured as halo spin parameter λ of the dark matter halo, on formation and evolutionary characteristics of the DM bars. Our systematic study involves haloes with initial spin configurations ranging from λ = 0 to 0.1. The result conveys that DM bar formation and its characteristics are extensively dependent on the initial spin parameter λ of the DM halo. We demonstrate that the strength of the dark matter bar gradually increases with an increase in halo spin in long-term evolution, with a significant impact of stellar bar buckling on dark matter bar strength. The evolutionary characteristics of the DM bar are strongly influenced by the initial spin of the host halo.
title The Role of Inner Halo Angular Momentum (Spin) in Shaping Dark Matter Bars in Milky Way Analogs
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2601.14420