Halpha surface photometry of galaxies in nearby clusters. V: the survey completion

TL;DR

This paper presents a comprehensive Halpha imaging survey of 273 late-type galaxies in nearby clusters, analyzing their star formation activity and its dependence on galaxy type, luminosity, and environment.

Contribution

It completes the Halpha survey for a representative sample of nearby galaxies, enabling detailed analysis of star formation and gas content in different cluster environments.

Findings

Halpha properties depend on Hubble type and luminosity.

Gaseous content partly explains the scatter in Halpha equivalent widths.

Luminous galaxies show decreased Halpha emission near cluster centers.

Abstract

We present the Halpha imaging observations of 273 late-type galaxies in the nearby rich galaxy clusters Virgo, A1367, Coma, Cancer, Hercules and in the Great Wall, carried out primarily with the 2.1m telescope of the San Pedro Martir Observatory (SPM) and with the ESO/3.6m telescope. We derived the Halpha+[NII] fluxes and equivalent widths. The Halpha survey reached completion for an optically selected sample of nearby galaxies in and outside rich clusters. Taking advantage of the completeness of the data set, the dependence of Halpha properties on the Hubble type was determined for late-type galaxies in the Virgo cluster. Differences in the gaseous content partly account for the large scatter of the Halpha E.W. within each Hubble-type class. We studied the radial distributions of the Halpha E.W. around Coma+A1367 and the Virgo clusters in two luminosity bins. Luminous galaxies show a decrease in their average Halpha E.W. in the inner 1 virial radius, while low-luminosity galaxies do not show this trend.