Comparing galaxy populations in compact and loose groups of galaxies III. Effects of environment on star formation

Abstract

This paper is part of a series in which we perform a systematic comparison of the galaxy properties inhabiting compact groups, loose groups and the field. In this paper we focus our study to the age and the star formation in galaxies. For galaxies in selected samples of compact groups, loose groups and field, we compare the distributions of the following parameters: D${}_n(4000)$ as an age indicator, and the specific star formation rate as indicator of ongoing star formation. We analyse the dependence of these parameters on galaxy type, stellar mass and, for group galaxies, their dependence on the dynamic state of the system. We also analyse the fraction of old, and of high star forming galaxies as a function of galaxy stellar mass in the environments we probe. Galaxies in compact groups have, on average, older stellar populations than their loose group or field counterparts. Early-type galaxies in compact groups formed their stars and depleted their gas content more rapidly than in the other environments. We have found evidence of two populations of late-type galaxies in dynamically old compact groups: one with normal specific star formation rates and another with markedly reduced star formation. Processes that transform galaxies from star forming to quiescent act upon galaxies faster and more effectively in compact groups. The unique characteristics of compact groups make them an extreme environment for galaxies, where the transition to quiescence occurs rapidly.

Accepted for publication in A&A. 7 pages, 6 figures

References in corpus (5)

• UV Star Formation Rates in the Local Universe
• The influence of the environmental history on quenching star formation in a $\Lambda$CDM universe
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• The Infrared Properties of Hickson Compact Groups
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Cited by in corpus (7)

• The Fastest Galaxy Evolution in an Unbiased Compact Group Sample with WISE
• Hickson-like compact groups inhabiting different environments
• On the nature of Small Galaxy Systems
• The Compactness of Galaxy Groups in the Sloan Digital Sky Survey
• Cosmic Pathways for Compact Groups in the Milli-Millennium Simulation
• Secondary Infall in the Seyfert's Sextet: A Plausible Way Out of the Short Crossing Time Paradox
• The $-12$ mag dip in the galaxy luminosity function of Hickson Compact Groups