//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25902 SUBJECT: GRB 191001B: Swift detection of a burst DATE: 19/10/01 17:39:17 GMT FROM: Scott Barthelmy at NASA/GSFC E. Troja (NASA/GSFC/UMCP), E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), V. D'Elia (SSDC), J. A. Kennea (PSU), N. J. Klingler (PSU), F. E. Marshall (NASA/GSFC), M. J. Moss (GWU), B. Sbarufatti (PSU) and A. Tohuvavohu (Toronto) report on behalf of the Neil Gehrels Swift Observatory Team: At 17:19:20 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 191001B (trigger=927345). Swift did not slew due to targets with higher priority. The BAT on-board calculated location is RA, Dec 86.368, -15.907 which is RA(J2000) = 05h 45m 28s Dec(J2000) = -15d 54' 25" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows several peaks with a total duration of about 25 sec. The peak count rate was ~1600 counts/sec (15-350 keV), at ~20 sec after the trigger. Due to higher priority observations, Swift will not slew to the BAT position. There will thus be no prompt XRT or UVOT data for this trigger. Burst Advocate for this burst is E. Troja (eleonora.troja AT 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/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25906 SUBJECT: GRB 191001B: MITSuME Akeno optical upper limits DATE: 19/10/01 18:52:08 GMT FROM: Katsuhiro L. Murata at Nagoya U K. L. Murata, R. Adachi, M. Oeda, K.Shiraishi, K. Iida, M. Niwano, F. Ogawa, R. Hosokawa, S. Toma, Y. Yatsu, and N. Kawai (TokyoTech) report on behalf of the MITSuME collaboration: We searched for the optical counterpart of GRB 191001B (E. Troja et al., GCN Circular #25902) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 17:22:09 UT. We did not find any new point sources within the BAT on-board calculated error circle in all three bands. We obtained the following 5-sigma limits for the magnitudes. T0+[sec] MID-UT T-EXP[sec] 5-sigma limits ------------------------------------------------------------------------------------------------ ~169 ~17:37 1680 g'>18.8, Rc>18.8, Ic>18.6 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used GSC2.3 catalog for flux calibration. The magnitudes are expressed in the AB system. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25930 SUBJECT: GRB 191001B: Swift-BAT refined analysis DATE: 19/10/02 23:53:19 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), E. Troja (NASA/GSFC/UMCP), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 191001B (trigger #927345) (Troja et al., GCN Circ. 25902). The BAT ground-calculated position is RA, Dec = 86.423, -15.880 deg which is RA(J2000) = 05h 45m 41.5s Dec(J2000) = -15d 52' 48.3" with an uncertainty of 3.6 arcmin, (radius, sys+stat, 90% containment). The partial coding was 33%. The mask-weighted light curve shows a multi-peaked structure that starts at ~T-10 s and ends at ~T+130 s. T90 (15-350 keV) is 108.9 +- 15.1 sec (estimated error including systematics). The time-averaged spectrum from T-8.77 to T+126.11 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.58 +- 0.11. The fluence in the 15-150 keV band is 4.6 +- 0.3 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+20.44 sec in the 15-150 keV band is 1.8 +- 0.4 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/927345/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25940 SUBJECT: GRB 191001B: Optical Upper Limits with LCO DATE: 19/10/03 18:30:36 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 191001B (Barthelmy et al., GCN 25902) with the LCO 1-m Sinistro instrument on October 2, from 01:23 to 01:47 UT (corresponding to 5.73 to 6.2 hours from the GRB trigger time) with the SDSS r’ and i’ filters. We performed a series of 5x120s exposures in each band. We do not detect any fading sources over the course of our observations in a 26.5' x 26.5' field of view centered around the Swift coordinates (Barthelmy et al., GCN 25902). Using the USNO-B.1 catalog as reference, we obtain the following 3-sigma upper limits: r > 18.82 i > 16.98 These observations were possible thanks to the USVI NASA-EPSCoR Research Infrastructure Development (RID) grant NNX16AL44A.