//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15028 SUBJECT: Swift Trigger 563980 is GRB 130725A DATE: 13/07/25 15:14:06 GMT FROM: Binbin Zhang at PSU B.-B. Zhang (PSU/UAH), S. D. Barthelmy (GSFC), M. M. Chester (PSU), D. Grupe (PSU), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), S. R. Oates (MSSL-UCL), H. A. Krimm (USRA/CRESST/GSFC), J. A. Kennea (PSU), Daniele Malesani (DARK/NBI), M. H. Siegel (PSU) and F. E. Marshall (NASA/GSFC) report on behalf of the Swift Team: At 11:37:11 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130725A (trigger=563980). Swift slewed to the burst. This burst was not identified in real-time due to telemetry gaps. The BAT on-board calculated location is RA, Dec 230.034,+0.624 which is RA(J2000) = 15h 20m 8s Dec(J2000) = +00d 37' 26" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 15 sec. The peak count rate was ~600 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 12:28:46 UT, 3094 seconds after the BAT trigger. Using 2.28 ks of ground-linked XRT data, we found an uncatalogued X-ray source located at RA, Dec = 230.033,+0.627, which is equivalent to: RA(J2000) = +15h 20m 07.92s Dec(J2000) = 00d 37' 40.2" with an uncertainty of 4.0 arc seconds (radius, 90% containment). UVOT took a finding chart exposure of 150 seconds with the White filter 3097 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 0.06. Further analysis is on-going. This circular is an official product of the Swift team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15031 SUBJECT: GRB 130725A, Swift-BAT refined analysis DATE: 13/07/25 19:05:30 GMT FROM: Hans Krimm at NASA-GSFC T. N. Ukwatta (MSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), B.-B. Zhang (PSU/UAH) (i.e. the Swift-BAT team): Using the data set from T-239 to T+731 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130725A (trigger #563980) (Zhang, et al., GCN Circ. 15028). The BAT ground-calculated position is RA, Dec = 230.060, 0.624 deg which is RA(J2000) = 15h 20m 14.4s Dec(J2000) = +00d 37' 26.8" with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 39%. The mask-weighted light curve shows a double-peaked structure lasting from approximately T+0 to T+20 seconds. This is followed by lower-level emission out to ~T+100 seconds. The source went out of the field of view at ~T+450 seconds, following a pre-planned slew. T90 (15-350 keV) is 101.8 +- 20.5 sec (estimated error including systematics). The time-averaged spectrum from T-9.83 to T+103.40 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.60 +- 0.30. The fluence in the 15-150 keV band is 9.7 +- 1.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+3.11 sec in the 15-150 keV band is 0.6 +- 0.2 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/563980/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15033 SUBJECT: GRB 130725A: MITSuME Ishigakijima Optical Observation DATE: 13/07/26 01:04:02 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 130725A (Zhang et al., GCNC 15028) 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 2013-07-25 13:34:52 UT (~2.0 h after the burst). We detected the afterglow candidate within the XRT error circle (Zhang et al., GCNC 15028) in only Rc band. Photometric result and three sigma upper limits of the OT are listed below. We used SDSS catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Rc_err Ic ---------------------------------------------------------------------- 0.10534 14:08:53 2280.0 >21.3 20.8 0.2 >19.8 ---------------------------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15035 SUBJECT: GRB 130725A - Faulkes Telescope South Observations DATE: 13/07/26 08:43:47 GMT FROM: Andrea Melandri at Liverpool John Moores U F.J. Virgili (LJMU), C. Guidorzi (U. Ferrara), J. Japelj, D. Kopac (U. Ljubljana), A. Melandri (INAF-OAB) report: "The 2-m Faulkes Telescope South robotically followed up GRB 130725A (SWIFT trigger 563980; Zhang et al. GCN 15028) beginning 111.9 min after the GRB trigger time. No optical counterpart is detected within the XRT error circle to the following conservative limits: Midtime from GRB Exposure Filter Magnitude (min) (s) ------------------------------------------------------------------------- 112.2 3x10s r' > 18.9 117.1 1x10s i' > 17 ------------------------------------------------------------------------- Values are calibrated against nearby SDSS field stars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15036 SUBJECT: GRB 130725A: Swift/UVOT Upper Limits DATE: 13/07/26 11:49:46 GMT FROM: Samantha Oates at MSSL S. R. Oates (UCL-MSSL) and B.-B. Zhang (PUS/UAH) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130725A (Zhang et al., GCN Circ. 15028) 3097 s after the BAT trigger (trigger=563980). No optical afterglow consistent with the XRT position 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 3097 3247 147 >21.1 white 3097 4480 344 >21.0 v 3255 10746 1278 >20.4 b 4075 5690 373 >20.4 u 3870 17226 1118 >21.0 w1 3665 16476 1279 >21.0 m2 3460 11458 1089 >21.0 w2 4486 9832 1082 >21.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 15042 SUBJECT: GRB 130725A: Swift-XRT refined Analysis DATE: 13/07/26 15:28:18 GMT FROM: Binbin Zhang at PSU B.-B. Zhang (PSU/UAH) reports on behalf of the Swift-XRT team: We have analysed 6.8 ks of XRT data for GRB 130725A, from 3.1 ks to 17.2 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. Using 3850 s of PC mode data and 5 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 230.03240, +0.62761 which is equivalent to: RA (J2000): 15h 20m 07.78s Dec(J2000): +00d 37' 39.4" with an uncertainty of 1.8 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=0.7 (+0.4, -0.3). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.5 (+0.6, -0.5). The best-fitting absorption column is 9 (+11, -5) x 10^20 cm^-2, consistent with the Galactic value of 4.3 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.9 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 9 (+11, -5) x 10^20 cm^-2 Galactic foreground: 4.3 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 2.5 (+0.6, -0.5) If the light curve continues to decay with a power-law decay index of 0.7, the count rate at T+24 hours will be 2.9 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.5 x 10^-14 (1.3 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00563980. This circular is an official product of the Swift-XRT team.