Burst Phase Distribution of SGR J1935+2154 Based on Insight-HXMT

On 2020 April 27, the soft gamma-ray repeater SGR J1935+2154 entered its intense outburst episode again. Insight-HXMT carried out about one month observation of the source. A total number of 75 bursts were detected during this activity episode by Insight-HXMT, and persistent emission data were also accumulated. We report on the spin period search result and the phase distribution of burst start times and burst photon arrival times of the Insight-HXMT high energy detectors and Fermi/Gamma-ray Burst Monitor (GBM). We find that the distribution of burst start times is uniform within its spin phase for both Insight-HXMT and Fermi/GBM observations, whereas the phase distribution of burst photons is related to the type of a burst's energy spectrum. The bursts with the same spectrum have different distribution characteristics in the initial and decay episodes for the activity of magnetar SGR J1935+2154.

Automated summary

On April 27, 2020, the soft gamma-ray repeater SGR J1935+2154 experienced another intense outburst. Insight-HXMT conducted a one-month observation of the source, detecting a total of 75 bursts and accumulating persistent emission data. The spin period search result and the phase distribution of burst start times and burst photon arrival times were analyzed for both Insight-HXMT and Fermi/Gamma-ray Burst Monitor (GBM). It was found that the distribution of burst start times is uniform within its spin phase, while the phase distribution of burst photons is dependent on the burst's energy spectrum.