出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：It has been known that sources with high absorption column density also have high dust column
density along the line of sight. The differential delays caused by small angle scattering of X rays
by dust may have important effects on the power spectra of Galactic black holes at low energies,
and impact studies that use the relation between the rms amplitude of variability and energy
to determine the origin of QPOs from these sources. We observed the high absorption column
density (NH 1023 cm−2) GBH 1E1740.7-2942 for 20 ks simultaneously with XMM-Newton and
RXTE. By comparing the power spectra from the events in the core of the point spread function
(PSF) of XMM-Newton EPIC-PN (using imaging and excluding the scattering halo) and the RXTE
data, we quantified the effects of small angle scattering on the timing properties of this source.
The rms amplitude of variability in2–6 keV band obtained fromthe XMM-Newton data is higher
than that of the RXTE as expected from the a scattering halo contribution in the RXTE.
