8 research outputs found
The complex X-ray spectrum of the isolated neutron star RBS1223
We present a first analysis of a deep X-ray spectrum of the isolated neutron
star RBS1223 obtained with XMM-Newton. Spectral data from four new monitoring
observations in 2005/2006 were combined with archival observations obtained in
2003 and 2004 to form a spin-phase averaged spectrum containing 290000 EPIC-pn
photons. This spectrum shows higher complexity than its predecessors, and can
be parameterised with two Gaussian absorption lines superimposed on a
blackbody. The line centers, E_2 ~ 2E_1, could be regarded as supporting the
cyclotron interpretation of the absorption features in a field B ~ 4 x 10**13
G. The flux ratio of those lines does not support this interpretation. Hence,
either feature might be of truly atomic origin.Comment: 4 pages, 1 figure, to appear in Astrophysics and Space Science, in
the proceedings of "Isolated Neutron Stars: from the Interior to the
Surface", edited by D. Page, R. Turolla and S. Zan