Speaker
Description
We present the assessment of scientific capabilities of the Gamma-ray Transient Monitor (GTM) for observing the Crab pulsar. GTM is the science payload on board FORMOSAT-8B (FS-8B), a remote sensing satellite of Taiwan Space Agency (TASA) to launch in late 2026. Two modules of GTM detectors are mounted on opposite (+y and -y) sides of FS-8B, and each consists of four sensor units comprising Gadolinium Aluminum Gallium Garnet (GAGG) scintillator arrays. The geometry of the sensors enables GTM to cover the whole sky at any time, including the directions occulted by the Earth. GTM is most sensitive in the energy range from 50 keV to 2 MeV.
The Crab is a standard candle in high-energy astrophysics, and has yet to be extensively studied in the MeV energy range. Our goals of the Crab pulsar study using GTM in this window include studying the synchrotron tail emission and monitoring possible flux variations. Through simulations with the Medium-Energy Gamma-ray Astronomy library (MEGAlib) in a high-inclination low-Earth-orbit radiation background, the count rates are estimated to be about 1 cps (pulsed component) and about 300 cps (nebula plus background) in the 50-300 keV range. These results indicate that an observation over 100 ks (~1 week, accounting for duty cycle) can achieve a detection significance exceeding 5σ for the pulsed emission. We also assess the instrument’s ability to perform spectral or even polarimetric analysis. These results highlight the mission’s potential to contribute to long-term monitoring and cross-validation with other observatories, demonstrating the additional scientific value of small telescope platforms.
| Participate the oral/poster presentation award competition | No |
|---|