XMM-Newton observations of the young open cluster Blanco 1 ^*,**

I. X-ray spectroscopy and photometry

¹ Dip. di Astronomia, Università di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy
² INAF – Osservatorio Astronomico di Palermo Piazza del Parlamento 1, 90134 Palermo, Italy e-mail: giusi@astropa.unipa.it, sciorti@astropa.unipa.it, damiani@astropa.unipa.it
³ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, UK e-mail: frh@cfa.harvard.edu

Corresponding author: I. Pillitteri, pilli@astropa.unipa.it

Received: 15 December 2003
Accepted: 10 March 2004

Abstract

We present an X-ray study of the high metallicity young open cluster Blanco 1 based on XMM-Newton data. X-ray spectroscopy of cluster members is presented for the first time as well as new X-ray distribution functions of late-type stars. We detected all known dF and dG stars in the EPIC field and 80% and 90% of dK and dM stars, respectively. The X-ray spectral analysis of the X-ray brightest cluster stars and X-ray color analysis of a larger sample show that a model with two temperatures (at about 0.3 and 1 keV) explains the quiescent activity phase spectra.
We discuss also the nature of unidentified X-ray sources in the observed region and their X-ray spectral properties.