1996A&AS..120C.295W

We present preliminary results of a search for flaring of the gamma-ray source 1E 1740.7-2942 above 300keV using the JPL-EBOP package on BATSE data. We selected two periods, 1-19 October 1991 and 19-20 September 1992, corresponding to SIGMA observations of a transient high energy feature in the spectrum of 1E 1740.7-2942 around 450keV. For the first period, we find an integrated 300-600keV flux consistent with SIGMA observation. Below 200keV, the interpretation is uncertain because of potential source confusion with BATSE. For the second period, the sensitivity of the current JPL-EBOP package does not allow us to put strong constraints on this ∼ one-day long flaring although no flux variation above 300keV is observed during a 13-day period including this event with a one-day one-sigma sensitivity of ∼3x10^–3ph/cm²/s.