Recent Soft Gamma Repeater Activity from Kes 73
ATel #16927; David M. Palmer (LANL) on behalf of the Swift Team
on 29 Nov 2024; 21:59 UT
Credential Certification: David M. Palmer (palmer@lanl.gov)
Subjects: X-ray, Gamma Ray, Soft Gamma-ray Repeater, Magnetar
Referred to by ATel #: 16928
Swift/BAT has detected recent SGR bursts from two sources: SGR 1E 1841-045 / Kes 73 (the subject of this ATel, and ATels #16784, #16786, #16789, #16799, #16802, and #16816) and SGR 1806-20 (which will be reported separately).
A third active soft gamma-ray repeater, SGR Swift J1818.0-1607 had a burst in 2024 August as reported by Lanza et al. (ATel #16837) but BAT has not detected any recent bursts from this source in its Field Of View (FOV).
The Kes 73 activity began in 2024 August and the most recent burst was today (2024 Nov 29 UT). Previously, it was last seen by BAT in October 2016.
The recent burst history for Kes 73 as seen by BAT, omitting bursts from 2016 and earlier, is shown in the following table.
| Time (UTC) |
Trigger duration (s) |
Fluence |
|
| 2024-08-20T19:01:18 | 0.032 | 1.55 ± 0.10 | |
| 2024-08-21T07:33:27 | 0.032 | 0.24 ± 0.04 | |
| 2024-08-21T12:16:10 | 0.064 | 4.20 ± 0.19 | |
| 2024-08-21T20:29:24 | 0.128 | 22.18 ± 0.88 | |
| 2024-11-11T19:12:43 | 0.016 | 0.79 ± 0.06 | |
| 2024-11-15T17:18:41 | 0.008 | 0.37 ± 0.04 | |
| 2024-11-29T10:56:49 | 0.032 | 6.88 ± 0.37 | |
Fluences are nominally in Crab-seconds, 15-50 keV, adjusted for instrument exposure.
The calibration is approximate and does not take spectral properties into account,
so fluence values should only be used for qualitative comparison among bursts from this and other SGRs.
