Résumé du preprint DAPNIA-02-108

Accretion Ejection Instability and QPO in the black hole binaries : 1.Observations
J. Rodriguez, P. Varniere, M. Tagger, Ph. Durouchoux
This is the first of two papers in which we address the physics of
 the low-frequency Quasi-Periodic Oscillation (QPO) of X-ray
 binaries, in particular those hosting a black hole.  We discuss and
 repeat the recent analysis and spectral modelling of the 
 micro-quasar GRO J1655-40  by Sobczak et al. (2000), and
 compare it with GRS 1915+105; this leads us to confirm and
 analyze in more detail the different behavior noted by Sobczak et al., between GRO J1655-40 and other sources, when comparing
 the correlation between the QPO frequency and the disk inner
 radius.  In a companion paper (Varni\\`ere et al. , 2002, hereafter
 Paper II) we will show that these opposite behaviors can be
 explained in the context of the Accretion-Ejection Instability
 recently presented by Tagger and Pellat (1999).
We thus propose that the difference between GRO J1655-40  and
 other sources comes from the fact that in the former, observed in a
 very high state, the disk inner radius always stays close to the
 Last Stable Orbit.  
In the course of this analysis, we also indicate interesting
 differences between the source properties, when the spectral fits
 give an anomalously low inner disk radius.  This might indicate the
 presence of a spiral shock or a hot point in the disk.


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