Astronomy and Astrophysics, volume 462, 657-666 (2007/2-1)
XMM-Newton and INTEGRAL spectroscopy of the microquasar GRO J1655-40 during its 2005 outburst.
DIAZ TRIGO M., PARMAR A.N., MILLER J., KUULKERS E. and CABALLERO-GARCIA M.D.
Abstract (from CDS):
We report on two simultaneous XMM-Newton and INTEGRAL observations of the microquasar GROJ1655-40 during the 2005 outburst when the source was in its high-soft state. The 0.3-200keV spectra are complex with an overall continuum which may be modeled using an absorbed blackbody together with a weak, steep, power-law component. In addition, there is evidence for the presence of both a relativistically broadened Fe K line and a highly photo-ionized absorber. The photo-ionized absorber is responsible for strong K absorption lines of FeXXV and FeXXVI in the EPIC pn spectra and blue-shifted (v=-540±120km/s) NeX and FeXXIV features in the RGS spectra. The parameters of the photo-ionized absorber were different during the two observations with the ionization parameter, log(ξ), decreasing from 3.60±0.04 to 3.30±0.04erg.cm/s and the column density decreasing from (5.2±1.0)x1022atom/cm2 to (1.5±1.0)x1022atom/cm2 during the first and second observations as the 0.5-200keV GROJ1655-40 luminosity decreased by around a half. At 90% confidence the INTEGRAL data show no evidence of a break in the power-law component up to energies of 380keV and 90keV for the first and second observations, respectively.