Ghosh, S and Saha, K and Jog, CJ and Combes, F and Di Matteo, P (2022) Genesis of morpho-kinematic lopsidedness in minor merger of galaxies. In: Monthly Notices of the Royal Astronomical Society, 511 (4). pp. 5878-5896.
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Abstract
An m = 1 lopsided asymmetry is common in disc galaxies. Here, we investigate the excitation of an m = 1 lopsidedness in host galaxies during minor mergers while choosing a set of 1:10 merger models (with varying orbital configurations, morphology of the host galaxy) from the GalMer galaxy merger library. We show that a minor merger triggers a prominent m = 1 lopsidedness in stars of the host galaxy. The strength of the m = 1 lopsidedness undergoes a transient amplification phase after each pericenter passage of the satellite, in concordance with past findings of exciting an m = 1 lopsidedness by tidal encounters. However, once the merger happens, and the post-merger remnant readjusts itself, the lopsidedness disappears in short time-scale (�500-850 Myr). Furthermore, a delayed merger can drive a prolonged (�2 Gyr) lopsidedness in the host galaxy. We demonstrate that the m = 1 lopsidedness rotates with a well-defined pattern speed which is much slower than the m = 2 bar pattern speed, and is retrograde with respect to the bar. This gives rise to a dynamical scenario where the Inner Lindblad resonance of the m = 1 lopsidedness falls in between the corotation and the Outer Lindblad resonance of the m = 2 bar mode. A kinematic lopsidedness also arises in the host galaxy; the resulting temporal variation closely follows that of the density lopsidedness. The minor merger also triggers a transient off-centred stellar disc-dark matter halo configuration due to the tidal encounter with the satellite. © 2022 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.
| Item Type: | Journal Article |
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| Publication: | Monthly Notices of the Royal Astronomical Society |
| Publisher: | Oxford University Press |
| Additional Information: | The copyright for this article belongs to authors. |
| Keywords: | Galaxies; Kinematics; Orbits, Disk galaxies; Galaxies: Kinematics and dynamics; Galaxies:structure; Galaxy evolution; Galaxy formations; Galaxy:halo; Host galaxies; Orbital configuration; Short time scale; Transient amplification, Merging |
| Department/Centre: | Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 17 May 2022 09:49 |
| Last Modified: | 17 May 2022 09:49 |
| URI: | https://eprints.iisc.ac.in/id/eprint/71766 |
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