Estudio óptico de LMXBS con alta resolución temporal evidencia de flares no térmicos en MXB 1735-44

Abstract

We present a search for ultrafast optical variability among some low-mass X-ray binaries (LMXBS) using MANIA complex (Multichannel Analisys of Nanosecond Intensity Alterations) attached to the 2.15 m telescope of CASLEO. Two flares of ∼ 0.25 sec in duration were recorded from the MXB 1735-44 X-ray burster. Brightness of the object increased 15-30 times during these flares, with very steep forward fronts (characteristic rising time being ∼ 0.05-0.06 sec), and displaying a fine structure in time-scale of 0.005-0.006 sec (confidence level > 95%). Brightness temperatures of these phases within the flares were more than 5x10⁷,10⁸ K, respectively, which can only be explained by non-thermal processes. These results are an evidence that in MXB 1735-44 there exist some departures from standard model of accretion onto compact objects.