Across the soft gamma-ray regime: utilizing simultaneous detections in the Compton Spectrometer and Imager (COSI) and the Background and Transient Observer (BTO) to understand astrophysical transients

• DOI: 10.48550/arxiv.2407.07155
• Publication Date: 2024-07-09
• Authors: Hannah Gulick; Eliza Neights; Samer Al Nussirat; Claire Tianyi Chen; Kaylie Ching; C. N. Dove; Alyson Joens; Carolyn Kierans; Hubert Liu; Israel Martinez; Romas Mician; Shunsaku Nagasawa; Shreya Nandyala; Isabel Schmidtke; D. D. Shah; Andreas Zoglauer; Kazuhiro Nakasawa; Tadayuki Takahashi; Juan-Carlos Marti...; John A. Tomsick
• Keywords: Transient (computer programming); Observer (physics)

The Compton Spectrometer and Imager (COSI) is a NASA funded Small Explorer (SMEX) mission slated to launch in 2027. COSI will house wide-field gamma-ray telescope designed survey the entire sky 0.2--5 MeV range. Using germanium detectors, instrument provide imaging, spectroscopy, polarimetry of astrophysical sources with excellent energy resolution degree-scale localization capabilities. In addition main instrument, fly student collaboration project known as Background Transient Observer (BTO). BTO extend bandpass energies lower than 200 keV, thus enabling spectral analysis across shared band 30 keV--2 consist two NaI scintillators student-designed readout electronics. information from both instruments, physics such peak turnover bursts, characteristics magnetar flares, event frequency range transient phenomena be constrained. this paper, we present expected science returnables comment on missions. We include simulations giant terrestrial flashes using BTO's response. Additionally, estimate burst detection rate find that detect ~150 bursts per year, most these events being long bursts.