The environments and clustering properties of 2dF Galaxy Redshift Survey selected starburst galaxies |
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| Authors: | Matt S Owers Chris Blake Warrick J Couch Michael B Pracy Kenji Bekki |
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| Institution: | School of Physics, University of New South Wales, Sydney, NSW 2052, Australia;Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122, Australia;Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2600, Australia |
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| Abstract: | We investigate the environments and clustering properties of starburst galaxies selected from the 2dF Galaxy Redshift Survey (2dFGRS) in order to determine which, if any, environmental factors play a role in triggering a starburst. We quantify the local environments, clustering properties and luminosity functions of our starburst galaxies and compare to random control samples. The starburst galaxies are also classified morphologically in terms of their broad Hubble type and evidence of tidal merger/interaction signatures. We find the starburst galaxies to be much less clustered on large (5–15 Mpc) scales compared to the overall 2dFGRS galaxy population. In terms of their environments, we find just over half of the starburst galaxies to reside in low to intermediate luminosity groups, and a further ～30 per cent residing in the outskirts and infall regions of rich clusters. Their luminosity functions also differ significantly from that of the overall 2dFGRS galaxy population, with the sense of the difference being critically dependent on the way their star formation rates are measured. In terms of pin-pointing what might trigger the starburst, it would appear that factors relating to their local environment are most germane. Specifically, we find clear evidence that the presence of a near neighbour of comparable luminosity/mass within 20 kpc is likely to be important in triggering a starburst. We also find that a significant fraction (20–30 per cent) of the galaxies in our starburst samples have morphologies indicative of either an ongoing or a recent tidal interaction and/or merger. These findings notwithstanding, there remain a significant portion of starburst galaxies where such local environmental influences are not in any obvious way playing a triggering role, leading us to conclude that starbursts can also be internally driven. |
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| Keywords: | surveys galaxy: active galaxies: evolution galaxies: formation galaxies: interactions galaxies: starburst |
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