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A deep Hα survey of galaxies in the two nearby clustersAbell 1367 and Coma^*

The Hα luminosity functions

¹ Laboratoire d'Astrophysique de Marseille, Traverse du Siphon – Les Trois Lucs, 13376 Marseille, France e-mail: jorge.iglesias@astrsp-mrs.fr;alessandro.boselli@astrsp-mrs.fr
² Università degli Studi di Milano – Bicocca, P.zza delle scienze 3, 20126 Milano, Italy e-mail: giuseppe.gavazzi@mib.infn.it; luca.cortese@mib.infn.it
³ Instituto de Astrofísica de Andalucía (CSIC), Granada, Spain e-mail: jvm@iaa.es

Corresponding author: J. Iglesias-Páramo, jorge.iglesias@astrsp-mrs.fr

Received: 13 November 2001
Accepted: 14 December 2001

Abstract

We present a deep wide field Hα imaging survey of thecentral regions of the two nearby clusters of galaxies Coma and Abell 1367, taken with theWFC at the INT 2.5 m telescope. We determine for the first time the Schechter parameters of the Hαluminosity function (LF) of cluster galaxies.The Hα LFs of Abell 1367 and Coma are compared with each other and with that ofVirgo, estimated using theB band LF by Sandage et al. ([CITE]) and aL(Hα) vs. M_B relation.Typical parameters of Mpc^-3, erg s^-1 and are found for the threeclusters. The best fitting parameters of the cluster LFs differ fromthose found for field galaxies, showing flatter slopes and lower scalingluminositiesL^*. Since, however, our Hα survey is significantly deeper thanthose of field galaxies, this result must be confirmed on similarly deepmeasurements of field galaxies.By computing the totalSFR per unit volume of cluster galaxies, and taking intoaccount the cluster density in the local Universe, we estimate that thecontribution of clusters like Coma and Abell 1367 is approximately 0.25%of theSFR per unit volume of the local Universe.