Predictions for Short Gamma-Ray Burst Detections by COSI

Eliza Neights; Eric Burns; Nicolò Parmiggiani; Yong Sheng; Savitri Gallego; Aldo Aguilar-Nadalini; Aaron C. Trigg; Sylvain Guiriec; Koothodil Abhijith Augustine; Matthew G. Baring; Anna L. Butterworth; Hsiang-Kuang Chang; Che-Yen Chu; Niccolò Di Lalla; Christopher Fryer; Hadar Lazar; Israel Martinez-Castellanos; Marion Sudvarg; Péter Veres; Steven E. Boggs; Dieter H. Hartmann; Carolyn A. Kierans; John A. Tomsick; Andreas Zoglauer

arXiv · 2610.08940

Predictions for Short Gamma-Ray Burst Detections by COSI

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Abstract

The Compton Spectrometer and Imager (COSI) is a soft gamma-ray telescope scheduled to launch in 2027. COSI will trigger onboard the spacecraft in response to short-duration transients, including gamma-ray bursts, and it will promptly disseminate alerts which include localizations to the community. This will enable rapid follow-up observations of the afterglow and associations with transients identified by other instruments. By simulating COSI observations of short gamma-ray bursts (sGRBs) and processing them with the trigger algorithm which will run onboard the spacecraft, we estimate the sensitivity of COSI to sGRBs. We then convolve this with a simulated set of sGRBs representing the intrinsic population in the universe to predict the rate that will be detected by COSI. We find that COSI is expected to trigger on $\sim$47-89 sGRBs per year with $\sim$7-10 localized to within 2.5°. With the gravitational wave sensitivity anticipated in the O5 run, we predict 0-3 joint detections with gravitational waves.

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Eliza Neights, Eric Burns, Nicolò Parmiggiani, Yong Sheng, Savitri Gallego, Aldo Aguilar-Nadalini, Aaron C. Trigg, Sylvain Guiriec, Koothodil Abhijith Augustine, Matthew G. Baring, Anna L. Butterworth, Hsiang-Kuang Chang, Che-Yen Chu, Niccolò Di Lalla, Christopher Fryer, Hadar Lazar, Israel Martinez-Castellanos, Marion Sudvarg, Péter Veres, Steven E. Boggs, Dieter H. Hartmann, Carolyn A. Kierans, John A. Tomsick, Andreas Zoglauer. 2026-10-06. Predictions for Short Gamma-Ray Burst Detections by COSI. https://arxiv.org/abs/2610.08940

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