Analysis Methods to Localize and Characterize X-Ray Sources with the Microchannel X-Ray Telescope on Board the SVOM Satellite

Abstract

The Space-based multiband astronomical Variableonboard computing resources. This Object Monitor (SVOM) is a Sino–French space mission targeting high-energy transient astrophysical objects such as gamma-ray bursts. The soft X-ray part of the spectrum is covered by the Microchannel X-ray Telescope (MXT), which is a narrow field telescope designed to localize X-ray sources precisely. This paper presents the methods implemented on board to characterize and localize X-ray sources with the MXT. A specific localization method was developed to accommodate the optical system of the MXT, which is based on “Lobster Eye” grazing incidence micropore optics. For the first time, the algorithm takes advantage of cross-correlation techniques to achieve a localization accuracy down to 2′ with fewer than 200 photons, which guarantees rapid follow-up for most of the gamma-ray bursts that SVOM will observe. In this paper, we also study the limitations of the algorithm and characterize its performance.