Insight-HXMT dedicated 33-day observation of SGR J1935+2154 II. Burst Spectral Catalog

Abstract

Since April 28, 2020, Insight-HXMT has implemented a dedicated observation on the magnetar SGR J1935+2154. Thanks to the wide energy band (1-250 keV) and high sensitivity of Insight-HXMT, we obtained 75 bursts from SGR J1935+2154 during a month-long activity episode after the emission of FRB 200428. Here, we report the detailed time-integrated spectral analysis of these bursts and the statistical distribution of the spectral parameters. We find that for 15%(11/75) of SGR J1935+2154 bursts, the CPL model is preferred, and most of them occurred in the latter part of this active epoch. In the cumulative fluence distribution, we find that the fluence of bursts in our sample is about an order of magnitude weaker than that of Fermi/GBM, but follows the same power law distribution. Finally, we find a burst with similar peak energy to the time-integrated spectrum of the X-ray burst associated with FRB 200428 (FRB 200428-Associated Burst), but the low energy index is harder.

35 pages, 20 figures, accepted for publication in ApJS

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Cited by in corpus (10)

• Discovery of the linear energy-dependence of the spectral lag of X-ray bursts from SGR J1935+2154
• Finding the Particularity of the Active Episode of SGR J1935+2154 during Which FRB 20200428 Occurred: Implication from Statistics of Fermi/GBM X-Ray Bursts
• GECAM Observations of the Galactic Magnetar SGR J1935+2154 during the 2021 and 2022 Burst Active Episodes. I. Burst Catalog
• Testing afterglow models of FRB 200428 with early post-burst observations of SGR 1935+2154
• FRB$-$SRB$-$XRB: Geometric and Relativistic Beaming Constraints of Fast Radio Bursts from the Galactic Magnetar SGR J1935+2154
• Statistical Properties of X-Ray Bursts from SGR J1935+2154 Detected by Insight-HXMT
• Burst phase distribution of SGR J1935+2154 based on Insight-HXMT
• Repeating X-ray bursts: Interaction between a neutron star and clumps partially disrupted from a planet
• Joint Observation of SGR J1935+2154 with \textit{Insight}-HXMT and KM40m during the active episode of October 2022
• Spectral Evidence of Heavy Nuclei from the Neutron Star Crust in Magnetar Bursts