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Title

Spatially resolved spectroscopy of starburst and post-starburst galaxies in the rich z~0.55 cluster CL 0016+16

Author(s)

Pracy, Michael B.;  Couch, Warrick J.;  Kuntschner, Harald

Abstract

We have used the Low Resolution Imaging Spectrograph on the W. M. Keck I telescope to obtain spatially resolved spectroscopy of a small sample of six ‘post-starburst’ and three ‘dusty-starburst’ galaxies in the rich cluster CL 0016+16 at z = 0.55. We use this to measure radial profiles of the Hδ and [OII]λ3727 lines which are diagnostic probes of the mechanisms that give rise to the abrupt changes in star formation rates in these galaxies. In the post-starburst sample we are unable to detect any radial gradients in the Hδ line equivalent width — although one galaxy exhibits a gradient from one side of the galaxy to the other. The absence of Hδ gradients in these galaxies is consistent with their production via interaction with the intra-cluster medium; however, our limited spatial sampling prevents us from drawing robust conclusions. All members of the sample have early-type morphologies, typical of post-starburst galaxies in general, but lack the high incidence of tidal tails and disturbances seen in local field samples. This argues against a merger origin and adds weight to a scenario where truncation by the intra-cluster medium is at work. The post-starburst spectral signature is consistent over the radial extent probed with no evidence of [OII]λ3727 emission and strong Hδ absorption at all radii, i.e. the post-starburst classification is not an aperture effect. In contrast the ‘dusty-starburst’ sample shows a tendency for a central concentration of [OII]λ3727 emission. This is most straightforwardly interpreted as the consequence of a central starburst. However, other possibilities exist such as a non-uniform dust distribution (which is expected in such galaxies) and/or a non-uniform starburst age distribution. The members of the sample exhibit late-type and irregular morphologies.

Publication type

Journal article

Research centre

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

Source

Publications of the Astronomical Society of Australia, Vol. 27, no. 3 (2010), pp. 360-373

Publication year

2010

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

CL 0016+16;  Galaxy clusters;  Galaxy evolution;  Post-starburst galaxies

Publisher

CSIRO Publishing

ISSN

1323-3580

Publisher URL

http://dx.doi.org/10.1071/AS10011

Copyright

Copyright © Astronomical Society of Australia 2010. Accepted manuscript of the paper reproduced here in accordance with the copyright policy of the publisher.

Full text

Peer reviewed