Spectro-temporal Studies of Microquasars in X-rays
by
Jérôme Rodriguez (ISDC, Geneva & CEA, Saclay)
→
Europe/Zurich
INTEGRAL Science Data Centre (isdc.unige.ch)
INTEGRAL Science Data Centre (isdc.unige.ch)
Description
Microquasars are binary systems in our Galaxy composed of a normal star
and a stellar mass black hole (or a neutron star). Their name comes from
the fact that the compact object ejects matter in powerful jets similar
to those observed in distant quasars. This talk will be dedicated to the
study of three microquasars, hosting a black hole, mainly through the
spectral and temporal properties of their soft (1-10 keV) and hard
(10-100 keV) X-ray emissions.
I will first briefly define and present the useful terms and the basic
physics underlying the phenomena occurring in the close vicinity of
these objects from both the spectral and temporal point of view.
I will then turn to the study of two microquasars, GRO J1655-40 and GRS
1915+105 and present the link between quasi-periodic oscillations
(QPO) and spectral parameters. I show how the spectro-temporal behavior
of both sources, although different, are in good agreement with the
theoretical predictions of the Accretion-Ejection Instability (AEI).
A third object, XTE J1550-564, will be then studied over a period of
outbursts. I will point out the presence of two different X-ray emitting
media, which relative geometry may be changing through the outburst.
I will also present the evolution of low frequency QPOs and compare it
to the theoretical predictions of some models of these features.
As a conclusion, I will discuss all these results in the framework of
theoretical models compatible with the observations presented along this talk.