| Issue |
A&A
Volume 553, May 2013
|
|
|---|---|---|
| Article Number | A67 | |
| Number of page(s) | 13 | |
| Section | Extragalactic astronomy | |
| DOI | https://doi.org/10.1051/0004-6361/201118390 | |
| Published online | 06 May 2013 | |
Star-forming galaxies in low-redshift clusters: Effects of environment on the concentration of star formation⋆
1 Astrophysics Research Institute, Liverpool John Moores University, Birkenhead, CH41 1LD, UK
e-mail: paj@astro.livjm.ac.uk
2 Carter Observatory, Wellington 6012, New Zealand
Received: 3 November 2011
Accepted: 18 March 2013
Aims. We attempt to determine the dominant processes acting on star-forming disk galaxies as a result of the cluster environment by studying the normalised rates and radial distributions of star formation in galaxies within low-redshift clusters.
Methods. We develop indicators of different processes based on the radial concentrations of R-band and Hα light within each of the galaxies studied. The tests are applied to galaxies in each of 3 environments – cluster, supercluster (outside the cluster virial radius) and field. We develop new diagnostic diagrams combining star-formation rate and spatial distribution information to differentiate between stripping of outer disk gas, general gas depletion, nuclear starbursts and galaxy-wide enhancement of star formation.
Results. Hubble type classifications of cluster galaxies are found to correlate only weakly with their concentration indices, whereas this correlation is strong for non-cluster populations of disk galaxies. We identify a population of early-type disk galaxies in the cluster population with both enhanced and centrally-concentrated star formation compared to their field counterparts. The enhanced cluster galaxies frequently show evidence of disturbance. A small but non-negligible population of cluster galaxies with truncation of star formation in their outer disks is also found.
Key words: galaxies: clusters: general / galaxies: evolution / galaxies: spiral / galaxies: star formation / galaxies: structure
Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias; and with the Jacobus Kapteyn Telescope, which was operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.
© ESO, 2013
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