The Gamma-ray Transients Monitor (GTM) on board Formosat-8B

Hsiang-Kuang Chang^1*, Chih-Hsun Lin², Che-Chih Tsao³, The GTM Collaboration^1,2,3,4

¹Institute of Astronomy, National Tsing Hua University, Hsinchu, Taiwan
²Institute of Physics, Academia Sinica, Taipei, Taiwan
³Department of Power Engineering, National Tsing Hua University, Hsinchu, Taiwan
⁴Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan

* Presenter:Hsiang-Kuang Chang, email:hkchang@mx.nthu.edu.tw

Gamma Ray Bursts (GRBs) were discovered more than half a century ago. Their nature remained highly mysterious since then until the detection of their multi-wavelength afterglows and host galaxies in the late 90’s, which provided opportunities to measure the redshift of GRBs and to establish their cosmological distance scale. These advances were based on extensive efforts of GRB monitoring and follow-up observations. The Gamma-ray Transients Monitor (GTM) on board Formosat-8B (FS-8B), a Taiwanese remote sensing satellite to launch in 2026, will join this effort to monitor GBRs in the energy band from 50 keV to 2 MeV. GTM consists of two identical modules located on two opposite sides of FS-8B. Each module has four sensor units facing different directions to cover half of the sky. The two modules will then cover the whole sky, including the direction occulted by the Earth. Each sensor unit is composed of a GAGG scintillator array (50 mm × 50 mm × 8 mm) to be readout by SiPM with 16 pixel-channels. GTM will enhance the sky coverage of current missions in the world and provide independent event localization measurement. It is expected to detect about 50 GRBs per year. GTM is Taiwan’s 1st space astronomy instrument.

Keywords: Gamma-ray transients, Space missions, MeV astronomical instrumentation