Generation of rotationally dominated galaxies by mergers of pressure-supported progenitors

Di Matteo, P and Jog, CJ and Lehnert, MD and Combes, F and Semelin, B (2009) Generation of rotationally dominated galaxies by mergers of pressure-supported progenitors. In: Astronomy & Astrophysics, 501 (3). L9-L13.

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Abstract

Through the analysis of a set of numerical simulations of major mergers between initially non-rotating, pressure-supported progenitor galaxies with a range of central mass concentrations, we have shown that: (1) it is possible to generate elliptical-like galaxies, with outside one effective radius, as a result of the conversion of orbital- into internal-angular momentum; (2) the outer regions acquire part of the angular momentum first; (3) both the baryonic and the dark matter components of the remnant galaxy acquire part of the angular momentum, the relative fractions depending on the initial concentration of the merging galaxies. For this conversion to occur the initial baryonic component must be sufficiently dense and/or the encounter should take place on an orbit with high angular momentum. Systems with these hybrid properties have recently been observed through a combination of stellar absorption lines and planetary nebulae for kinematic studies of early-type galaxies. Our results are in qualitative agreement with these observations and demonstrate that even mergers composed of non rotating, pressure-supported progenitor galaxies can produce early-type galaxies with significant rotation at large radii.

Item Type:	Journal Article
Publication:	Astronomy & Astrophysics
Publisher:	EDP Sciences
Additional Information:	copyright of this article belongs to EDP Sciences.
Keywords:	galaxies:interactions;galaxies:ormation;galaxies: evolution; galaxies:structure;methods:N-body simulations; galaxies:kinematics and dynamics.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	26 Aug 2009 04:19
Last Modified:	19 Sep 2010 05:41
URI:	http://eprints.iisc.ac.in/id/eprint/22283

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