GRB 210121A: A Typical Fireball Burst Detected by Two Small Missions
Abstract
The Chinese CubeSat Mission, Gamma Ray Integrated Detectors (GRID), recently detected its first gamma-ray burst, GRB 210121A, which was jointly observed by the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM). This burst is confirmed by several other missions, including Fermi and Insight-HXMT. We combined multimission observational data and performed a comprehensive analysis of the burst's temporal and spectral properties. Our results show that the burst is relatively special in its high peak energy, thermal-like low-energy indices, and large fluence. By putting it to the E p -E γ,iso relation diagram with assumed distance, we found that this burst can be constrained at the redshift range of [0.3, 3.0]. The thermal spectral component is also confirmed by the direct fit of the physical models to the observed spectra. Interestingly, the physical photosphere model also constrained a redshift of z ~ 0.3 for this burst, which helps us to identify a host galaxy candidate at such a distance within the location error box. Assuming that the host galaxy is real, we found that the burst can be best explained by the photosphere emission of a typical fireball with an initial radius of r 0 ~ 3.2 × 107 cm.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2021
- DOI:
- 10.3847/1538-4357/ac29bd
- arXiv:
- arXiv:2107.10452
- Bibcode:
- 2021ApJ...922..237W
- Keywords:
-
- Gamma-ray bursts;
- 629;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- ApJ accpeted