We report on INTEGRAL observations of the two microquasars GX 339−4 and 1E 1740.7−2942. Even though both sources are black hole candidates in LMXB systems, GX 339−4 has a transient behaviour, while the prototype of microquasars, 1E 1740.7−2942, is a persistent, even though variable source. We analysed a uniform data-set of GX 339−4 observations collected during the 2004 outburst using all INTEGRAL instruments. Observations were long enough to cover transitions between spectral states. Moreover, IBIS and SPI spectra of GX 339−4 showed a high energy excess with respect to pure thermal Comptonisation model, even during the hard/intermediate state. We analysed three years of SPI and IBIS data of 1E 1740.7−2942 during which two main states have been observed: the canonical low/hard state of black-hole candidates and a "dim" state, characterised by a ∼ 20 times fainter emission. The low/hard state spectrum up to ∼ 600 keV is well represented by a thermal Comptonisation plus an additional component modeling data above 200 keV. finally, we summarise results and make a comparison between the two sources.

We present here the main characteristics of the BHC IGR J17091-3624 outbursts occurred several times since 1994. Since 2003, the source has been extensively observed by INTEGRAL and Swift. In particular, we report results on the last 2011 outburst that showed a rare variability behaviour observed before only in the galactic BH GRS 1915+105 but at a different level of flux.Several hypotheses have been proposed in order to explain this particular behaviour. They are all discussed here, in the light of their apparent contradiction. Finally, based on all available informations, we attempt to give an overall view of this enigmatic source and we speculate on the evolutionary state of the binary system. An INTEGRAL view of the high-energy sky (the first 10 years) -9th INTEGRAL Workshop and celebration of the 10th anniversary of the launch

We present six years of INTEGRAL (IBIS, SPI and JEM-X) observations of the BH binary Cygnus X-1. We produced 12 high-quality broad-band spectra (3 keV-1 MeV), representative of the whole range of spectral shapes observed in this source. We have studied the evolution of the physical parameters of the accretion flow across spectral transitions, by using two hybrid thermal/non-* Based on observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark,

We report on INTEGRAL observations performed during the 2004 outburst of the bright black hole transient GX 339−4. We analysed IBIS and JEM-X public data starting on 9th August and lasting about one month. During this period GX 339−4 showed spectral state transitions. In order to seek for variability patterns, a principal component analysis (PCA) has been used. VI