3-200 keV spectral states and variability of the INTEGRAL black hole binary IGR J17464-3213

On March 2003, IBIS, the gamma-ray imager on board the INTEGRAL satellite, detected an outburst from a new source, IGR J17464-3213, that turned out to be a HEAO 1 transient, H1743-322. In this paper we report on the high-energy behavior of this black hole candidate (BHC) studied with the three main instruments on board INTEGRAL. The data, collected with unprecedented sensitivity in the hard X-ray range, show a quite hard Comptonized emission from 3 up to 150 keV during the rising part of the source outburst, with no thermal emission detectable. A few days later, a prominent soft-disk multicolor component appears, with the hard tail luminosity almost unchanged: similar to 5 x 10(-9) ergs cm(-2) s(-1). Two months later, during a second monitoring campaign near the end of the outburst, the observed disk component was unchanged. Conversely, the Comptonized emission from the central hot part of the disk reduced by a factor of similar to 10. We present here its long-term behavior in different energy ranges and the combined JEM-X, SPI, and IBIS wideband spectral evolution of this source.