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Title

The role of dissipation in the scaling relations of cosmological merger remnants

Author(s)

Covington, M. D.;  Primack, J. R.;  Porter, L. A.;  Croton, D. J.;  Somerville, R. S.;  Dekel, A.

Abstract

There are strong correlations between the three structural properties of elliptical galaxies - stellar mass, velocity dispersion and size - in the form of a tight 'Fundamental Plane' and a 'scaling relation' between each pair. Major mergers of disc galaxies are assumed to be a mechanism for producing ellipticals, but semi-analytic galaxy formation models (SAMs) have encountered apparent difficulties in reproducing the observed slope and scatter of the size-mass relation. We study the scaling relations of merger remnants using progenitor properties from two SAMs. We apply a simple merger model that includes gas dissipation and star formation based on theoretical considerations and simulations. Combining the SAMs and the merger model allows the calculation of the structural properties of the remnants of major mergers that enter the population of elliptical galaxies at a given redshift. Without tuning the merger model parameters for each SAM, the results roughly match the slope and scatter in the observed scaling relations and their evolution in the redshift range z= 0-3. Within this model, the observed scaling relations, including the tilt of the Fundamental Plane relative to the virial plane, result primarily from the decrease of gas fraction with increasing progenitor mass. The scatter in the size-mass relation of the remnants is reduced from that of the progenitors because of a correlation between progenitor size and gas fraction at a given mass.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Monthly Notices of the Royal Astronomical Society, Vol. 415, no. 4 (Aug 2011), pp. 3135-3152

Publication year

2011

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

Elliptical galaxies;  Galaxy evolution;  Galaxy formation;  Galaxy interactions;  Lenticular galaxies

Publisher

Wiley-Blackwell Publishing

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2011.18926.x

Copyright

Copyright © 2011 The Authors. Journal compilation copyright © 2011 Royal Astronomical Society. The accepted manuscript is reproduced in accordance with the copyright policy of the publisher. The definitive publication is available at www.interscience.wiley.com.

Full text

Peer reviewed