EDP Sciences
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Volume 384, Number 2, March III 2002
Page(s) 383 - 392
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20011830

A&A 384, 383-392 (2002)
DOI: 10.1051/0004-6361:20011830

A deep H $\alpha$ survey of galaxies in the two nearby clusters Abell 1367 and Coma

The H $\alpha$ luminosity functions
J. Iglesias-Páramo1, A. Boselli1, L. Cortese2, J. M. Vílchez3 and G. Gavazzi2

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

(Received 13 November 2001 / Accepted 14 December 2001 )

We present a deep wide field H $\alpha$ imaging survey of the central regions of the two nearby clusters of galaxies Coma and Abell 1367, taken with the WFC at the INT 2.5 m telescope. We determine for the first time the Schechter parameters of the H $\alpha$ luminosity function (LF) of cluster galaxies. The H $\alpha$ LFs of Abell 1367 and Coma are compared with each other and with that of Virgo, estimated using the B band LF by Sandage et al. (1985) and a L(H $\alpha$) vs.  MB relation. Typical parameters of $\phi^{*} \approx 10^{0.00\pm0.07}$ Mpc -3, $L^{*} \approx
10^{41.25\pm0.05}$  erg s -1 and $\alpha \approx -0.70\pm0.10$ are found for the three clusters. The best fitting parameters of the cluster LFs differ from those found for field galaxies, showing flatter slopes and lower scaling luminosities L*. Since, however, our H $\alpha$ survey is significantly deeper than those of field galaxies, this result must be confirmed on similarly deep measurements of field galaxies. By computing the total SFR per unit volume of cluster galaxies, and taking into account the cluster density in the local Universe, we estimate that the contribution of clusters like Coma and Abell 1367 is approximately 0.25% of the SFR per unit volume of the local Universe.

Key words: atlases -- galaxies -- ISM: HII regions -- galaxies: clusters: individual: Abell 1367; Coma; Virgo

Offprint request: J. Iglesias-Páramo, jorge.iglesias@astrsp-mrs.fr

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