Building on SVOM : the CATCH satellite constellation for transient astronomy

Abstract

Building on the success of the French-Chinese SVOM mission, our consortium proposes CATCH (Chasing All Transients Constellation of Hunters), targeting Gamma-Ray Bursts and X-ray transients. Its first step, CATCH-PM (Precursor Mission), consists of three satellites: (i) the Trigger Scout Satellite (TSS), providing real-time detection and localization of transients from soft X-rays to gamma-rays; (ii) the X-ray Hunter Satellite (XHS), performing rapid X-ray afterglow follow-up and refined localization with Wolter-I optics; and (iii) the Infrared Hunter Satellite (IHS), enabling precise localization and follow-up in the visible and near-infrared, including obscured and high-redshift transients. CATCH-PM is both a technological demonstrator and a standalone time-domain astrophysics mission. In addition to Scout triggers, it will accept numerous external Targets of Opportunity and conduct a broad observing program. By reusing available spare hardware, a launch within five years is feasible. Operating alongside SVOM and EinsteinProbe, it would significantly enhance the overall scientific return.

contribution to the 2026 Very High Energy Phenomena in the Universe session of the 60th Rencontres de Moriond; 4 pages, 1 figure