Off-center dark matter halo leading to strong central disk lopsidedness

Prasad, Chaitanya and Jog, Chanda J (2017) Off-center dark matter halo leading to strong central disk lopsidedness. In: ASTRONOMY & ASTROPHYSICS, 600 .

PDF Ast_Ast_600_A17_2017.pdf - Published Version Restricted to Registered users only Download (368kB) | Request a copy

Abstract

There is increasing evidence from simulations and observations that the center of the dark matter halo in a Milky Way-type galaxy could be off-center by a few 100 pc with respect to the galactic disk. We study the effect of such an offset halo on the orbits and kinematics in the central few kpc of the disk via a simple, analytical model. The equations of motion in the disk plane can be written in terms of the potentials of the disk and halo when they are concentric, and a perturbation term arising due to the offset halo. We show that this perturbation potential has an m = 1 azimuthal variation, or is lopsided, and its magnitude increases at small radii. On solving these equations, we find that the perturbed orbit shows a large deviation, similar to 40% in radius at R = 1.5 kpc, and also strong kinematical lopsidedness. Thus, even a small halo offset of 350 pc can induce surprisingly strong spatial and kinematical lopsidedness in the central region within a similar to 3 kpc radius. The disk lopsidedness would have important implications for the evolution of this region; for example, it could help fuel the central active galactic nucleus.

Item Type:	Journal Article
Publication:	ASTRONOMY & ASTROPHYSICS
Additional Information:	Copy right for this article belongs to the EDP SCIENCES S A, 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	10 Jun 2017 04:39
Last Modified:	10 Jun 2017 04:39
URI:	http://eprints.iisc.ac.in/id/eprint/57175

Actions (login required)

View Item