University of Oulu

Ferré-Mateu, A., Forbes, D., Romanowsky, A., Janz, J., Dixon, C. (2017) On the formation mechanisms of compact elliptical galaxies. Monthly Notices of the Royal Astronomical Society, 473 (2), 1819-1840. doi:10.1093/mnras/stx2442

On the formation mechanisms of compact elliptical galaxies

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Author: Ferré-Mateu, Anna1; Forbes, Duncan A.1; Romanowsky, Aaron J.2,3;
Organizations: 1Centre for Astrophysics and Supercomputing, Swinburne University of Technology
2Department of Physics and Astronomy, San José State University
3University of California Observatories
4Centre for Astrophysics and Supercomputing, Swinburne University of Technology
5Astronomy Research Unit, University of Oulu
6Finnish Centre of Astronomy with ESO (FINCA), University of Turku
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 6.5 MB)
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Language: English
Published: Oxford University Press, 2018
Publish Date: 2017-12-07


In order to investigate the formation mechanisms of the rare compact elliptical (cE) galaxies, we have compiled a sample of 25 cEs with good SDSS spectra, covering a range of stellar masses, sizes and environments. They have been visually classified according to the interaction with their host, representing different evolutionary stages. We have included clearly disrupted galaxies, galaxies that despite not showing signs of interaction are located close to a massive neighbour (thus are good candidates for a stripping process), and cEs with no host nearby. For the latter, tidal stripping is less likely to have happened and instead they could simply represent the very low-mass, faint end of the ellipticals. We study a set of properties (structural parameters, stellar populations, star formation histories and mass ratios) that can be used to discriminate between an intrinsic or stripped origin. We find that one diagnostic tool alone is inconclusive for the majority of objects. However, if we combine all the tools a clear picture emerges. The most plausible origin, as well as the evolutionary stage and progenitor type, can be then determined. Our results favour the stripping mechanism for those galaxies in groups and clusters that have a plausible host nearby, but favours an intrinsic origin for those rare cEs without a plausible host and that are located in looser environments.

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Series: Monthly notices of the Royal Astronomical Society
ISSN: 0035-8711
ISSN-E: 1365-2966
ISSN-L: 0035-8711
Volume: 473
Issue: 2
Pages: 1819 - 1840
DOI: 10.1093/mnras/stx2442
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: AFM and DAF thank the ARC for financial support via DP160101608. AJR was supported by NSF grant AST-1515084 and as a Research Corporation for Science Advancement Cottrell Scholar.
Copyright information: © 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Published in this repository with the kind permission of the publisher.