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astro-ph.HE · High Energy Astrophysical Phenomena

Fermi GBM and GCN records show no SGR J1935+2154 burst from 2022-12-14 to 2026-11-08; four published activity periods (127-238 d) did not predict this silence or the 2021-2022 bursts

SGR J1935+2154 is the Galactic magnetar linked to FRB 200428. Four papers report periodic burst activity with periods of 231 d, 238 d, 126.88 d and 134.63 d. We test their active windows with data that came after each model. We use the Fermi GBM trigger catalog (snapshot 2026-11-09) and the GCN Circular archive. The last burst that we can attribute to the source occurred on 2022-12-13. No well-localized GBM trigger and no GCN report attributes a burst to it up to 2026-11-08. This 1,426-day quiet interval is the longest since discovery in 2014; the previous longest was 1,134 days. The models predicted 5.8 to 11 active windows from 2023-01 to 2026-11, and all were empty. With the window-activity rate of each training span, the probability of this silence is 0.012 to 0.027 (238 d), 0.016 (231 d), 0.067 (126.88 d) and 4e-5 (134.63 d). Bursts from 2020 to 2022 were not in the windows more often than random phase shifts predict (p = 0.14 to 0.72). The published 238-d windows missed the December 2021 to February 2022 episode. No trial period from 60 to 400 d gives an unusually small window that contains all 2014-2022 burst days (global p = 0.56). Renewal fits to the 2014-2022 quiet gaps give 0.0007 to 0.004 for the current gap (3e-5 to 0.047 for other episode definitions). Thus the data do not show a stable periodic window, and the source is quieter than stationary models predict. A decrease in long-term activity agrees with the data. Limitations: the record contains only bursts that triggered GBM or were reported in GCN circulars; fainter bursts are not in it. Two short, poorly localized GRB-class triggers 14 deg away (2025-10-12, 2026-09-28) are not attributed; a worst-case check with the first one gives similar conclusions. Code, derived tables, data hashes and figures are included.

astronomy · magnetar · SGR J1935+2154 · soft gamma repeater · burst activity · periodicity · forecast test · Fermi GBM · GCN circulars · fast radio burst · quiescence · renewal model

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References

7
  1. challengesdoi:10.48550/arXiv.2006.16480

    We test its 231-day windowed periodicity with later bursts and the 2023-2026 silence.

  2. challengesdoi:10.48550/arXiv.2107.03800

    We test its 238-day period and its Table 3 predicted windows with later data.

  3. challenges, supportsdoi:10.48550/arXiv.2205.08003

    We test its 126.88-day window; our results support its view that no period fits the full burst history.

  4. challengesdoi:10.48550/arXiv.2307.01010

    We test its 134.63-day period and 80 percent window with the 2023-2026 data.

  5. doi:10.48550/arXiv.2602.10895

    Reports the October 2022 FRB-associated X-ray burst in the last active episode.

  6. useshttps://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigtrig.html

    Fermi GBM trigger catalog, snapshot 2026-11-09.

  7. useshttps://gcn.nasa.gov/circulars

    GCN Circular archive, snapshot 2026-11-08.

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