Spectral evolution of bright NS LMXBs
Abstract
Theoretical and observational support suggests that the spectral evolution of neutron-star LMXBs, including transient hard X-ray tails, may be explained by the interplay between thermal and bulk motion Comptonization. In this framework, we developed a new model for the X-ray spectral fitting XSPEC package which takes into account the effects of both thermal and dynamical (i.e. bulk) Comptonization, CompTB. Using data from the INTEGRAL satellite, we tested our model on broad band spectra of a sample of persistently low magnetic field bright neutron star Low Mass X-ray Binaries, covering different spectral states. The case of the bright source GX 5-1 is presented here. Particular attention is given to the transient powerlaw-like hard X-ray (above 30 keV) tail that we interpret in the framework of the bulk motion Comptonization process, qualitatively describing the physical conditions of the environment in the innermost part of the system.
Keywords
Cite
@article{arxiv.1001.4014,
title = {Spectral evolution of bright NS LMXBs},
author = {A. Paizis and R. Farinelli and L. I. Mainardi and L. Titarchuk},
journal= {arXiv preprint arXiv:1001.4014},
year = {2010}
}
Comments
6 pages, 4 figures. Accepted for publication on PoS (contribution PoS(extremesky2009)059), proceedings of "The Extreme sky: Sampling the Universe above 10 keV", held in Otranto (Italy) in October 2009