INTEGRAL observations of the peculiar BeX System SAX J2103.5+4545

Institut de Ciència dels Materials, Universitat de València, 46071 Paterna-Valencia, Spain e-mail: pere.blay@uv.es

Received: 3 May 2004
Accepted: 21 July 2004

Abstract

We present an INTEGRAL data analysis of the X-ray transient SAX J2103.5+4545 during two outbursts detected in December 2002. The INTEGRAL coordinates and error circle agree with the position of the recently proposed optical counterpart. A power-law plus cut-off model provided a good fit to the 4–150 keV spectrum yielding a photon index of , a cut-off energy keV and a folding energy keV. The X-ray luminosity in the 4-150 keV energy range was found to be erg s^-1, assuming a distance of 6.5 kpc. This luminosity, together with the derived photon index, indicate that the source is in a bright state. A second pulse period is measured. This value is significantly smaller than previous measurements, indicating a long-term spin-up episode.