Broadband Comparisons between the Multiwavelength Behavior of Two Interesting X-ray Novae, XTE J1817-330 and XTE J1818-245

International audienceThe INTEGRAL satellite extensively observed XTE J1817-330 and XTE J1818-245 which underwent X-ray outbursts from, respectively, Jan. 2006 and Feb. 2005 to Nov. 2006, during the INTEGRAL Core Program and Target of Opportunity observations, dedicated to new X-ray novae, and during Galactic Bulge observations. We report some results of simultaneous multiwavelength observations of these black holes candidates performed with INTEGRAL, RXTE and with REM and ATCA for XTE J1817-330 and Swift, VLA, REM and EMMI for XTE J1818-245. Both sources are active up to 250 keV. Component evolutions occur in the accretion disk and in the hot medium (well fitted by Comptonization), with spectral changes in the hard and soft components correlated with puzzling changes in the radio and excess over a black body disk in the optical. ©2008 American Institute of Physic