//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8833 SUBJECT: AXP 1E1547.0-5408 activity with SGR bursts DATE: 09/01/22 02:25:39 GMT FROM: David Palmer at LANL C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL), M. Stamatikos (NASA/ORAU) and L. Vetere (PSU) report on behalf of the Swift Team: At 01:32:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located the known Anomalous X-Ray Pulasr AXP 1E1547.0-5408 (trigger=340573). Swift could not slew to this burst due to Earth limb constraint. The BAT on-board calculated location is RA, Dec 237.705, -54.320 which is RA(J2000) = 15h 50m 49s Dec(J2000) = -54d 19' 10" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed the typical short (<128 ms) spike of a Soft Gamma Repeater. The peak count rate was ~30,000 counts/sec (15-350 keV), at ~0 sec after the trigger. There are additional similar bursts visible in the light curve at T-40 and T+160 seconds. In addition at least 4 similar bursts had been seen by the Fermi GBM in the previous hour. An additional burst triggered BAT at T+37 minutes (Trigger 340578) which showed a multiple peak structure with a maximum count rate of 170,000 counts/s. SGR bursts from this source were last seen in early October 2008. XRT and UVOT will observe this source when it emerges from Earth limb constraint at 02:23 UT. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8834 SUBJECT: Trigger 340734: Swift detection of a possible short burst DATE: 09/01/22 08:01:26 GMT FROM: David Palmer at LANL D. Grupe (PSU), W. H. Baumgartner (GSFC/UMBC), S. Campana (INAF-OAB), P. A. Evans (U Leicester), C. Gronwall (PSU), J. A. Kennea (PSU), D. M. Palmer (LANL), J. L. Racusin (PSU) and L. Vetere (PSU) report on behalf of the Swift Team: At 07:30:06 UT, the Swift Burst Alert Telescope (BAT) triggered and located a possible GRB (trigger=340734). Swift slewed immediately to the calculated location. The BAT on-board calculated location is RA, Dec 263.343, -60.135 which is RA(J2000) = 17h 33m 22s Dec(J2000) = -60d 08' 05" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak with a duration of about 0.5 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 07:31:09.3 UT, 63.5 seconds after the BAT trigger. No source was detected in the promptly available XRT data. We are waiting for the full dataset to detect and localise the XRT counterpart. UVOT took a finding chart exposure of 150 seconds with the White filter starting 66 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 25% of the BAT error circle. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the sub-image. The coverage of the BAT error circle by the 8'x8' region is 100%. Because of the density of catalogued stars, further analysis is required to report an upper limit for any afterglow in the region. No correction has been made for the expected extinction corresponding to E(B-V) of 0.07. This trigger had a light curve duration and intensity similar to the SGR bursts from the newly reactivated AXP 1E1547.0-5408 (GCN 8833). The peak found in the image at the above location is of marginal significance. There is no XRT source found in the immediately available TDRSS data. For these reasons, it is possible that this trigger is due to a rate trigger due the AXP followed by a fluctuation in the image domain. Confirmation of the reality of this possible GRB will require analysis of the full dataset from Malindi. Burst Advocate for this burst is D. Grupe (grupe AT astro.psu.edu). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8835 SUBJECT: AXP 1E1547.0-5408: Fermi GBM observations DATE: 09/01/22 08:39:21 GMT FROM: Valerie Connaughton at MSFC Valerie Connaughton (UAH) and Michael Briggs (UAH) report on behalf of the Fermi GBM Team: "At 00:53:52.17 UT on 22 Jan 2009, the Fermi Gamma-Ray Burst Monitor triggered on AXP 1E1547.0-5408 (trigger 254278434 / 090122037). Since then, GBM has seen 18 triggers from this source including one trigger also detected by the Swift-BAT (Palmer et al. 2009, GCN 8833). The trigger rate is consistent with constant source activity in the form of short and often very bright pulses occurring within an interval of a few seconds to about 150s between pulses. We estimate the source activity is constant because the time between triggers is between 600s and 740s outside of SAA passages and periods during which the source is occulted by the Earth. The minimum possible trigger spacing for GBM is 596 seconds. Because of the high data rate these triggers have caused, it is not yet possible to perform spectral analysis of any of these events. We estimate from our real-time data, however, that the source is visible at least up to 100 keV and is not visible above 300 keV." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8837 SUBJECT: AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase DATE: 09/01/22 16:22:32 GMT FROM: Volodymyr Savchenko at ISDC,U of Geneve V. Savchenko, V. Beckmann, A. Neronov (ISDC), S. Mereghetti (INAF/IASF-Milano), A. von Kienlin (MPE), M. Beck (ISDC), J. Borkowski (CAMK/Torun), D. Gotz (CEA/Saclay) report on behalf of the INTEGRAL SPI-ACS GRB team: The SPI Anti-Coincidence System (ACS) on-board INTEGRAL has detected burst activity most likely arising from the AXP 1E1547.0-5408, as reported based on Swift/BAT (GCN 8834, 8833) and Fermi GBM data (GCN 8835). From 2009-01-22T00:42:05 until 10:49:56 UT, 167 short (from 50ms to 8s) intense bursts were detected with significance from 5 to 160 sigma (1e4 - 2e6 counts/s peak count rate). The SPI-ACS light curves of triggered events are available (both as images and data files) at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi The light curves, binned at 50 ms, are derived from 91 independent detectors with different lower energy thresholds (mainly between 50 keV and 150 keV) and an upper threshold at about 100 MeV. The ACS response varies as a function of the GRB incident angle. For these reasons we caution that the count rates cannot be easily translated into physical flux units. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8838 SUBJECT: AXP 1E1547.0-5408: Fermi GBM detection of additional bursts DATE: 09/01/22 16:27:07 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) and V. Connaughton (UAH) report on behalf of the Fermi GBM Team: "Since the first 18 triggers from AXP 1E1547.0-5408 detected by the Fermi Gamma-ray Burst Monitor on 22 January 2009 (GCN 8835, Connaughton & Briggs), there have been 13 additional triggers of Fermi GBM from this source. The GBM on-board locations are all consistent with the AXP 1E1547.0-5408 position. So there are a total of 31 triggered bursts from this source. Many other bursts were recorded during times where GBM was still in trigger mode. List of all GBM triggers since the first trigger on 00:53:52.17 UT: # Trigcat Trigger UTC ---------------------------------------------- 1 GBM 090122.037 254279434 00:53:52.17 2 GBM 090122.044 254279035 01:03:53.93 3 GBM 090122.052 254279656 01:14:14.88 4 GBM 090122.059 254280306 01:25:04.31 5 GBM 090122.104 254284211 02:30:09.39 6 GBM 090122.113 254284945 02:42:23.17 7 GBM 090122.120 254285611 02:53:29.75 8 GBM 090122.129 254286352 03:05:50.39 9 GBM 090122.173 254290113 04:08:31.65 10 GBM 090122.180 254290769 04:19:27.62 11 GBM 090122.187 254291369 04:29:27.73 12 GBM 090122.194 254291971 04:39:29.95 13 GBM 090122.218 254294023 05:13:41.02 14 GBM 090122.243 254296159 05:49:17.55 15 GBM 090122.252 254297017 06:03:36.00 16 GBM 090122.283 254299678 06:47:56.78 17 GBM 090122.291 254300306 06:58:24.25 18 GBM 090122.310 254301991 07:26:29.66 19 GBM 090122.317 254302590 07:36:28.75 20 GBM 090122.352 254305576 08:26:14.53 21 GBM 090122.359 254306192 08:36:30.55 22 GBM 090122.380 254308060 09:07:38.67 23 GBM 090122.390 254308862 09:21:00.39 24 GBM 090122.419 254311386 10:03:04.66 25 GBM 090122.428 254312201 10:16:39.36 26 GBM 090122.451 254314172 10:49:30.19 27 GBM 090122.491 254317583 11:46:21.33 28 GBM 090122.498 254318256 11:57:34.06 29 GBM 090122.551 254322796 13:13:14.53 30 GBM 090122.584 254325635 14:00:33.44 31 GBM 090122.624 254329074 14:57:52.72 Spectral analysis results will be reported soon." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8839 SUBJECT: Swift-BAT trigger 340734 is not a GRB DATE: 09/01/22 18:42:03 GMT FROM: Scott Barthelmy at NASA/GSFC S.D. Barthelmy (GSFC) and T. Sakamoto (GSFC/UMBC) (on behalf of the Swift-BAT team): Using the full data set from recent telemetry downlinks, we conclude that Swift-BAT trigger 340734 is not due to a GRB. This trigger is another outburst from the AXP 1E1547.0-5408 source.