%0 Journal Article
%T Spectral and temporal properties of X-ray emission from the ultra-luminous source X-9 in M81
%A V. La Parola
%A G. Fabbiano
%A D. W. Kim
%A G. Peres
%J Physics
%D 2001
%I arXiv
%X We have analysed the spectra and the variability of individual X-ray sources in the M-81 field using data from the available ROSAT-PSPC and ROSAT-HRI observations of this nearby spiral galaxy. Here we present the results on the second brightest source in the field (X-9 - Fabbiano, 1988 ApJ 325 544), whose identification and interpretation is still unclear. Our work includes the study of the shape of X-9 from HRI data, the light curve and hardness ratio evolution, and the spectral analysis.
%U http://arxiv.org/abs/astro-ph/0102111v2