Spectrophotometry of Galaxies in the Virgo Cluster. I. The Star Formation History

Abstract

As a result of an extensive observational campaign targeting the Virgo Cluster, we obtained integrated (drift-scan mode) optical spectra and multiwavelength (UV, U, B, V, H) photometry for 124 and 330 galaxies, respectively, spanning the whole Hubble sequence, and with mp =10 Gyr, whereas giant spirals have solar metallicities and τ~3 Gyr, consistent with elliptical galaxies. Moreover, we find that the SFH of spiral galaxies in the Virgo Cluster depends upon the presence at their interior of fresh gas capable of sustaining the star formation. In fact, the residuals of the τ vs. LH relation depend significantly on the H I content. H I deficient galaxies have shorter (up to a factor of 4) τ (truncated SFH) than spirals with normal H I content. Based on observations collected at the Observatoire de Haute Provence (OHP) (France), operated by the CNRS, France, and at the European Southern Observatory (Chile) (programme 66.B-0026).