Recent Burst Activity of EXO 0748-676/UY Volantis
ATel #16790; David Palmer (LANL) on behalf of the Swift/BAT team
on 26 Aug 2024; 23:15 UT
Credential Certification: David M. Palmer (palmer@lanl.gov)
Subjects: X-ray, Gamma Ray, Neutron Star, Transient
Recent Burst Activity of EXO 0748-676/UY Volantis
David Palmer (LANL) on behalf of the Swift/BAT team
The Burst Alert Telescope (BAT) instrument on Swift has
detected five X-ray bursts from the Low Mass X-ray Binary
EXO 0748-676 (=UY Volantis) since June 2024.
The first burst triggered an automatic follow-up and was reported
previously (D'Elia et al., GCN #36653).
Additional bursts have been reported by other instruments (see table).
These bursts were detected by BAT on rate-trigger timescales
from 2-8 seconds and imaged to identify them as coming from
this source. The trigger times (UTC) and Swift trigger
numbers for these bursts, in addition to other published
bursts from this source, are:
| 2024-06-10T07:36:36 | Swift #1236151 (GCN #36653) |
| 2024-06-13T19:23 | (Maxi/GSC; ATel #16654) |
| 2024-06-15T12:23:11 | Swift #1237121 |
| 2024-06-23T08:58 | (NinjaSat; ATel #16678) |
| 2024-07-01T07:28(ap) | (XMM-Newton; ATel #16753) |
| 2024-07-24T17:31:33 | (AstroSat; ATel #16753) |
| 2024-07-25T16:31:03 | (AstroSat; ATel #16753) |
| 2024-07-26T14:45:53 | (AstroSat; ATel #16753) |
| 2024-07-29T12:05:16 | Swift #1245446 |
| 2024-08-11T13:17:49 | Swift #1248126 |
| 2024-08-20T11:36:09 | Swift #1249610 |
The bursts seen by BAT are roughly similar in size and shape,
with durations of 10-15 s and peak fluxes of 300-500 counts/s
(15-350 keV) in the BAT detector.
BAT previously detected this source in on-board imaging only
between October 2005 and May 2008 in untriggered images
on timescales of 1 minute and longer.
Because this is a known source and the bursts were of
low intensity, Swift did not make automatic follow-ups
of the later bursts. However, Swift has been reconfigured
to slew and make UVOT and XRT observations on the next
detection.
