Periodicity Search on X-Ray Bursts of SGR J1935+2154 Using 8.5 yr of Fermi/GBM Data

We performed a systematic search for X-ray bursts of the SGR J1935+2154 using the Fermi Gamma-ray Burst Monitor continuous data dated from 2013 January to 2021 October. Eight bursting phases, which consist of a total of 353 individual bursts, are identified. We further analyze the periodic properties of our sample using the Lomb–Scargle periodogram. The result suggests that those bursts exhibit a period of ∼238 days with a ∼63.2% duty cycle. Based on our analysis, we further predict two upcoming active windows of the X-ray bursts. Since 2021 July, the beginning date of our first prediction has been confirmed by the ongoing X-ray activities of the SGR J1935+2154.