Comprehensive Bayesian analysis of FRB-like bursts from SGR 1935+2154 observed by CHIME/FRB
| Autor: | Giri, Utkarsh, Andersen, Bridget C., Chawla, Pragya, Curtin, Alice P., Fonseca, Emmanuel, Kaspi, Victoria M., Lin, Hsiu-Hsien, Masui, Kiyoshi W., Sand, Ketan R., Scholz, Paul, Abbott, Thomas C., Dong, Fengqiu Adam, Gaensler, B. M., Leung, Calvin, Michilli, Daniele, Bhardwaj, Mohit, Münchmeyer, Moritz, Pandhi, Ayush, Pearlman, Aaron B., Pleunis, Ziggy, Rafiei-Ravandi, Masoud, Reda, Alex, Shin, Kaitlyn, Smith, Kendrick, Stairs, Ingrid H., Stenning, David C., Tendulkar, Shriharsh P. |
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| Rok vydání: | 2023 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | The bright millisecond-duration radio burst from the Galactic magnetar SGR 1935+2154 in 2020 April was a landmark event, demonstrating that at least some fast radio burst (FRB) sources could be magnetars. The two-component burst was temporally coincident with peaks observed within a contemporaneous short X-ray burst envelope, marking the first instance where FRB-like bursts were observed to coincide with X-ray counterparts. In this study, we detail five new radio burst detections from SGR 1935+2154, observed by the CHIME/FRB instrument between October 2020 and December 2022. We develop a fast and efficient Bayesian inference pipeline that incorporates state-of-the-art Markov chain Monte Carlo techniques and use it to model the intensity data of these bursts under a flexible burst model. We revisit the 2020 April burst and corroborate that both the radio sub-components lead the corresponding peaks in their high-energy counterparts. For a burst observed in 2022 October, we find that our estimated radio pulse arrival time is contemporaneous with a short X-ray burst detected by GECAM and HEBS, and Konus-Wind and is consistent with the arrival time of a radio burst detected by GBT. We present flux and fluence estimates for all five bursts, employing an improved estimator for bursts detected in the side-lobes. We also present upper limits on radio emission for X-ray emission sources which were within CHIME/FRB's field-of-view at trigger time. Finally, we present our exposure and sensitivity analysis and estimate the Poisson rate for FRB-like events from SGR 1935+2154 to be $0.005^{+0.082}_{-0.004}$ events/day above a fluence of $10~\mathrm{kJy~ms}$ during the interval from 28 August 2018 to 1 December 2022, although we note this was measured during a time of great X-ray activity from the source. Comment: 22 pages, 6 figures, 4 tables. To be submitted to ApJ |
| Databáze: | arXiv |
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