//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8457 SUBJECT: Swift-BAT triggered on a probable GRB 081101 (trigger=333320) DATE: 08/11/01 12:21:04 GMT FROM: Scott Barthelmy at NASA/GSFC M. Stamatikos (NASA/ORAU), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), N. P. M. Kuin (MSSL), V. La Parola (INAF-IASFPA), C. B. Markwardt (CRESST/GSFC/UMD), D. M. Palmer (LANL) and P. Romano (INAF-IASFPA) report on behalf of the Swift Team: At 11:46:31 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 081101 (trigger=333320). Swift did not slew because of the low merit value assignment because of the chance spatial coincidence with the A0620-00 blackhole candidate source. The BAT on-board calculated location is RA, Dec 95.826, -0.082 which is RA(J2000) = 06h 23m 18s Dec(J2000) = -00d 04' 55" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single hard spike with a duration of less than 128 msec. The peak count rate was ~7000 counts/sec (15-350 keV), at ~0 sec after the trigger. We can not rule out that this was from A0620-00, although the position is a very unlikely 18 arcmin away. Thus, we believe this to be a gamma-ray burst, or possibly a new SGR (although the spectrum is harder than typical SGR bursts). Burst Advocate for this burst is M. Stamatikos (michael AT milkyway.gsfc.nasa.gov). 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: 8458 SUBJECT: SGR 0623-0006 or GRB 081101: Swift-BAT/-XRT refined analysis DATE: 08/11/01 16:35:16 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), C. B. Markwardt (GSFC/UMD), D. M. Palmer (LANL), M. Stamatikos (GSFC/ORAU), J. Kennea (PSU), V. Mangano (INAF-IASFPa), V. LaParola (INAF-IASFPA), P. Romano (INAF-IASFPA), N. P. M. Kuin (MSSL) (on behalf of the Swift-BAT/-XRT teams): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 081101 (trigger #333320) (Stamatikos, et al., GCN Circ. 8457). The BAT ground-calculated position is RA, Dec = 95.836, -0.112 deg, which is RA(J2000) = 06h 23m 20.7s Dec(J2000) = -00d 06' 41.5" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 50%. The mask-weighted light curve shows a single spike starting at ~T-0.05 sec, peaking at ~T+0.1 sec, and ending by ~T+0.3 sec. T90 (15-350 keV) is 0.20 +- 0.02 sec (estimated error including systematics). The time-averaged spectrum from T+0.0 to T+0.2 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.24 +- 1.12, and Epeak of 78 +- 34 keV (chi squared 62.8 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 6.2 +- 1.0 x 10^-8 erg/cm2 and the 1-sec peak flux measured from T-0.38 sec in the 15-150 keV band is 3.6 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.25 +- 0.20 (chi squared 69.9 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The BAT results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/333320/BA/ Swift/XRT began observing the field at 13:37:56 UT, 111 minutes after the BAT trigger, and observed the field in photon counting mode for 200 sec. No point sources were detected in the field of view. Observations of this field are ongoing. Given the short single spike form of the BAT lightcurve and the somewhat soft spectral values, this suggests that this is an SGR. We can not rule out a GRB explanation of this event. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8460 SUBJECT: GRB 081101 (or SGR 0623-0006 ): Fermi GBM detection DATE: 08/11/02 06:27:35 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE), E. Bissaldi (MPE), M.S. Briggs (UAHuntsville) and C. Kouveliotou (NASA/MSFC) report on behalf of the Fermi GBM Team: "At 11:46:32 UT on 01 November 2008, the Fermi GBM triggered and located an event (trigger 247232793 / 081101491) which was also seen by SWIFT (Stamatikos et al. 2008, GCN 8457, Barthelmy et al. 2008, GCN 8458). The GBM on-ground location is consistent with the Swift position. The GBM light curve shows a single peak with duration of about 224 ms. The event is significantly detected with GBM between 40 - 200 keV. The time-averaged spectrum from T0-0.103 s to T0+0.121 s is best fit by a single power law with index -1.14 +/- 0.07 (chi squared 212 for 234 d.o.f.). The event fluence (50-300 keV) in the same time interval is (1.6 +/- 0.08) E-07 erg/cm^2. The Swift team suggested that the event could be a possible new Soft Gamma Repeater (SGR 0623-0006). The GBM spectrum is more consistent with that of a faint short GRB; the lack of photons below 40 keV is rather unusual for an SGR. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 8486 SUBJECT: GRB 081101B: Fermi GBM detection DATE: 08/11/06 12:17:16 GMT FROM: Elisabetta Bissaldi at MPE E. Bissaldi (MPE) and A. von Kienlin (MPE) report on behalf of the Fermi GBM Team: "At 12:45:24.08 UT on November 01, 2008, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 081101B (trigger 247236325 / 081101532). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 212.5 deg, Dec = -31.1 deg (equivalent to J2000 14h 10m, -31d 06'), with a statistical uncertainty of 1.9 degrees (radius, 1-sigma containment; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 116 degrees. This GRB consists of one main emission phase comprising several overlapping pulses, with an estimated T90 (8-1000 keV) of about 8 s and T50 (8-1000 KeV) of about 5 s. The time-averaged spectrum from T0 to T0+7.680 s is best fit by a power law function with an exponential high energy cutoff. The power law index is -0.62 +/- 0.05 and the cutoff energy, parameterized as Epeak, is 550 +/- 30 keV. The event fluence (8-1000 keV) in this time interval is (1.60 +/- 0.03)E-05 erg/cm^2. The 1-sec photon flux measured starting from T0+1.536 s in the 8-1000 keV band is 10.3 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."