//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13147 SUBJECT: GRB 120328A: Swift detection of a burst DATE: 12/03/28 03:19:16 GMT FROM: David Palmer at LANL C. Pagani (U Leicester), W. H. Baumgartner (GSFC/UMBC), N. Gehrels (NASA/GSFC), E. A. Hoversten (PSU), A. Y. Lien (NASA/GSFC/ORAU), O. M. Littlejohns (U Leicester), F. E. Marshall (NASA/GSFC), C. J. Mountford (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. Stamatikos (OSU/NASA/GSFC), C. A. Swenson (PSU), T. N. Ukwatta (MSU) and B.-B. Zhang (PSU) report on behalf of the Swift Team: At 03:06:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120328A (trigger=518792). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 241.550, -39.340 which is RA(J2000) = 16h 06m 12s Dec(J2000) = -39d 20' 24" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with broad peak preceding a shorter spike for a total duration of about 20 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 03:07:27.2 UT, 68.2 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source located at RA, Dec 241.61294, -39.33664 which is equivalent to: RA(J2000) = 16h 06m 27.11s Dec(J2000) = -39d 20' 11.9" with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 175 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.61 x 10^21 cm^-2, Kalberla et al. 2005), with an excess column of 1.5 (+0.62/-0.52) x 10^22 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 1.53e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 78 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 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.73. Burst Advocate for this burst is C. Pagani (cp232 AT star.le.ac.uk). 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: 13148 SUBJECT: Skynet/PROMPT observations of GRB120328A DATE: 12/03/28 03:39:28 GMT FROM: Aaron LaCluyze at U.North Carolina J. Haislip, A. LaCluyze, K. Ivarsen, D. Reichart, J. Moore, H. T. Cromartie, R. Egger, A. Foster, N. Frank, M. Nysewander, A. Oza, E. Speckhard, A.Trotter, and J. A. Crain report: Skynet observed the field of GRB120328A (Pagani et al., GCN 13147, Swift trigger #518792) with the PROMPT telescopes located at CTIO in Chile beginning 4.1 minutes after the burst. We do not detect any uncatalogued sources in our earliest images (mean time 4.43 minutes after the burst) down to 3-sigma limiting magnitudes of V=17.92, R=18.73, I=18.15. Stacking all data taken up to 17.2 minutes after the burst yields 3-sigma limiting magnitudes of B=19.19, V=19.75, R=20.26, I=19.38. Limits were calibrated to nearby USNO-B1.0 stars for B,R,I, and nearby NOMAD stars for V. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13151 SUBJECT: GRB 120328A: TAROT La Silla observatory optical observations DATE: 12/03/28 05:19:00 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR), Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 120328A detected by SWIFT (trigger 518792) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 345.7s after the GRB trigger. The elevation of the field increased from 26 degrees above horizon and weather conditions were good. Images are unfiltered. We do not detect any OT with a limiting magnitude of: t0+345.7s to t0+405.7s : R > 18.5 Magnitudes were estimated with the nearby NOMAD1 stars and are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=339.0212 lat= +9.5155 and the galactic extinction in R band is ~2 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13153 SUBJECT: GRB 120328A: Enhanced Swift-XRT position DATE: 12/03/28 06:12:44 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) report on behalf of the Swift-XRT team. Using 763 s of XRT Photon Counting mode data and 1 UVOT images for GRB 120328A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 241.61376, -39.33565 which is equivalent to: RA (J2000): 16h 06m 27.30s Dec (J2000): -39d 20' 08.3" with an uncertainty of 1.9 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13154 SUBJECT: GRB 120328A: Swift-BAT refined analysis DATE: 12/03/28 12:17:01 GMT FROM: Scott Barthelmy at NASA/GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. Pagani (U Leicester), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from recent telemetry downlinks, we report further analysis of BAT GRB 120328A (trigger #518792) (Pagani, et al., GCN Circ. 13147). The BAT ground-calculated position is RA, Dec = 241.607, -39.322 deg, which is RA(J2000) = 16h 06m 25.8s Dec(J2000) = -39d 19' 20.8" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows two overlapping peaks. The first starts at ~T-20 sec, peaks at ~T+0; the second peaks at ~T+8 sec and ends at ~T+20 sec. T90 (15-350 keV) is 24.2 +- 6.7 sec (estimated error including systematics). The time-averaged spectrum from T-17.27 to T+20.61 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.87 +- 0.20. The fluence in the 15-150 keV band is 4.7 +- 0.6 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.11 sec in the 15-150 keV band is 0.7 +- 0.1 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/518792/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13159 SUBJECT: GRB 120328A: Swift-XRT refined Analysis DATE: 12/03/28 15:19:06 GMT FROM: Phil Evans at U of Leicester D.N. Burrows (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), V. D'Elia (ASDC), A. Maselli (INAF-IASFPA), V. Mangano (INAF-IASFPA), J.A. Kennea (PSU), M.C. Stroh (PSU) and C. Pagani report on behalf of the Swift-XRT team: We have analysed 9.0 ks of XRT data for GRB 120328A (Pagani et al. GCN Circ. 13147), from 62 s to 34.2 ks after the BAT trigger. The data comprise 139 s in Windowed Timing (WT) mode (the first 5 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Beardmore et al. (GCN. Circ 13153). The late-time light curve (from T0+4.1 ks) can be modelled with a power-law decay with a decay index of alpha=0.98 (+0.22, -0.20). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.5 (+0.4, -0.3). The best-fitting absorption column is 1.5 (+0.4, -0.3) x 10^22 cm^-2, in excess of the Galactic value of 1.6 x 10^21 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 3.0 (+0.5, -0.4) and a best-fitting absorption column of 1.9 (+0.5, -0.4) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.7 x 10^-11 (3.9 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.9 (+0.5, -0.4) x 10^22 cm^-2 Galactic foreground: 1.6 x 10^21 cm^-2 Excess significance: 6.9 sigma Photon index: 3.0 (+0.5, -0.4) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00518792. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13161 SUBJECT: GRB 120328A: Swift/UVOT Upper Limits DATE: 12/03/28 16:02:39 GMT FROM: Erik Hoversten at Swift/Penn State E. A. Hoversten (PSU) and C. Pagani (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 120328A 78 s after the BAT trigger (Pagani et al., GCN Circ. 13147). No optical afterglow consistent with the enhanced XRT position (Beardmore el al., GCN Circ. 13153) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 78 228 147 >20.6 u_FC 290 540 246 >19.6 white 78 764 186 >20.5 v 621 813 39 >18.2 b 547 739 39 >19.1 u 290 715 265 >19.8 w1 670 862 39 >18.9 w2 769 789 20 >18.6 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.73 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13171 SUBJECT: GRB 120328A: MITSuME Ishigakijima Optical Upper Limits DATE: 12/03/29 14:08:13 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda (OAO, NAOJ), H. Hanayama, T. Miyaji, J. Watanabe (IAO, NAOJ), K. Yanagisawa (OAO, NAOJ), S.Nagayama (NAOJ), M. Yoshida (Hiroshima), K. Ohta (Kyoto) and N. Kawai(Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 120328A (Pagani et al., GCNC 13147) with the optical three color (g', Rc and Ic) CCD camera attached to the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory. The observation started on 2012-03-28 18:34:18 UT (~15.5 h after the burst). We did not find any new point source within the enhanced XRT error circle (Beardmore et al., GCNC 13153) in all the three bands. Three sigma upper limits of the OT are listed below. We used GSC2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ---------------------------------------------------------------------- 0.68772 19:36:38 4800.0 >20.1 >20.4 >19.3 ---------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec]