//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14551 SUBJECT: Trigger 555096: Swift detection of a possible burst DATE: 13/05/04 02:29:39 GMT FROM: David Palmer at LANL J. R. Cummings (NASA/UMBC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), D. N. Burrows (PSU), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), M. H. Siegel (PSU), E. Troja (NASA/GSFC/UMCP) and T. N. Ukwatta (MSU) report on behalf of the Swift Team: At 02:05:34 UT, the Swift Burst Alert Telescope (BAT) triggered and located trigger=555096. Swift slewed immediately to the transient. The BAT on-board calculated location is RA, Dec 272.365, -16.344 which is RA(J2000) = 18h 09m 27s Dec(J2000) = -16d 20' 38" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed two FRED peaks with a duration of about 25 sec. The peak count rate was ~1617 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 02:07:00.2 UT, 85.9 seconds after the BAT trigger. No source was detected in 1.1 ks of promptly downlinked 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 88 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. 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 BAT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. The event is unusual in that it is a long burst in BAT with no detected X-ray counterpart after an immediate slew. We also note that this location is in the Galactic bulge near the plane (lon = 13.65, lat=1.56). Ground analysis of the detector plane histogram finds only a marginal image detection (5.9 sigma). For these reasons, we will not be able to determine the reality or nature of this event until ground-linked data is available. Burst Advocate for this burst is J. R. Cummings (jayc 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: 14553 SUBJECT: Swift-XRT X-ray afterglow candidate for GRB 130504A (BAT trigger 555096) DATE: 13/05/04 09:28:24 GMT FROM: Phil Evans at U of Leicester P. D'Avanzo (INAF-OAB), A. Melandri (INAF-OAB), K.L. Page (U. Leicester), P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: We have analysed 654 s of XRT data for GRB 130504A, from 99 s to 754 s after the BAT trigger. The data are entirely in Photon Counting (PC) mode. No X-ray afterglow is detected within the BAT error circle (Cummings et al. GCN 14551). We note however the presence of a bright, uncatalogued, fading X-ray source at the following refined position RA, Dec = 272.45484, -16.31423 which is equivalent to: RA (J2000): 18 09 49.16 Dec(J2000): -16 18 51.2 with an uncertainty of 3.5 arcsec (radius, 90% confidence). This position is about 5.5 arc min away from the BAT position. Given its fading nature, we propose it as the X-ray afterglow of GRB 130504A. The light curve can be modelled with a power-law decay with a decay index of alpha=0.79 (+/-0.19). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.7 (+/-0.4). The best-fitting absorption column is 1.6 (+0.5, -0.4) x 10^22 cm^-2, in excess of the Galactic value of 8.1 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 7.4 x 10^-11 (1.3 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.6 (+0.5, -0.4) x 10^22 cm^-2 Galactic foreground: 8.1 x 10^21 cm^-2 Excess significance: 2.8 sigma Photon index: 1.7 (+/-0.4) If the light curve continues to decay with a power-law decay index of 0.79, the count rate at T+24 hours will be 0.021 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.5 x 10^-12 (2.8 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00555096. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14554 SUBJECT: GRB 130504A, Swift-BAT refined analysis DATE: 13/05/04 11:08:22 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift D. M. Palmer (LANL), 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), A. Y. Lien (NASA/GSFC/ORAU), C. B. Markwardt (GSFC), T. Sakamoto (AGU), G. Sato (ISAS), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) Using the data set from T-61 to T+242 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130504A (trigger #555096) (Cummings, et al., GCN Circ. 14551). The BAT ground-calculated position is RA, Dec = 272.459, -16.320 deg which is RA(J2000) = 18h 09m 50.1s Dec(J2000) = -16d 19' 13.1" with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. This position is 5.3 arcmin away from the automated flight position reported in GCN circular# 14551. The imaging interval selected onboard was not optimum. The refined error circle includes the position of the XRT afterglow candidate reported by D'Avanzo et al. in GCN circular# 14553, hence we believe that fading x-ray source to be the correctly identified afterglow of GRB 130504A. The mask-weighted light curve shows multiple weak peaks. T90 (15-350 keV) is 50 +- 10 sec (estimated error including systematics). The time-averaged spectrum from T-31.07 to T+36.84 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 0.52 +- 0.68, and Epeak of 84.5 +- 47.6 keV (chi squared 82.16 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-06 erg/cm2 and the 1-sec peak flux measured from T-0.06 sec in the 15-150 keV band is 0.9 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.41 +- 0.15 (chi squared 88.43 for 57 d.o.f.). 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/555096/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14556 SUBJECT: GRB 130504A: Swift/UVOT Upper Limits DATE: 13/05/04 13:46:27 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (MSSL-UCL) and J. R. Cummings (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130504A 89s after the BAT trigger (Cummings et al., GCN Circ. 14551), but the GRB position is outside the field of view for several exposures. No optical afterglow consistent with the XRT position (D'Avanzo et al. GCN Circ. 14553) 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 u filter finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag u_FC 301 551 246 >19.8 white 858 1008 147 >20.5 w1 680 6058 333 >20.2 m2 655 7093 356 >20.4 w2 606 6878 549 >20.8 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 3.22 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14558 SUBJECT: GRB 130504A: Enhanced XRT position DATE: 13/05/04 16:47:01 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo (INAF-OAB), P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team: Using 3463 s of XRT Photon Counting mode data and 5 UVOT images, 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 = 272.45604, -16.31339 which is equivalent to: RA (J2000): 18 09 49.45 Dec (J2000): -16 18 48.2 with an uncertainty of 1.7 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 is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14559 SUBJECT: GRB 130504A: Bassano Bresciano Observatory optical upper limit DATE: 13/05/04 17:23:59 GMT FROM: Ulisse Quadri at Bassano Bresciano Obs U.Quadri, L.Strabla, R.Girelli and A.Quadri report: We imaged the field of GRB 130504A detected by SWIFT(trigger 555096) with the robotic telescopes of (IAU station 565) Bassano Bresciano Observatory, Italy. The observations started automatically 2 min 42 sec after the GRB trigger, with our schmidt telescope D=400 mm F/D=3 and our Newton telescope D=250mm F/D=5.5. Weather conditions were good. We co-added 2 series of 10 unfiltered CCD exposures of 120s each. We did not found any optical counterpart in the error box of the XRTcandidate (Cummings et al. GCN 14551) and in error box of X-ray afterglow candidate (P. D'Avanzo (INAF-OAB), A. Melandri (INAF-OAB) et al. GCN 14553) at our following limiting magnitude: . Start End Vlim 2.7min 52min 18.0 Magnitudes were estimated with the USNO-B1 cat. and are not corrected for galactic dust extinction. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14560 SUBJECT: GRB 130504B: Fermi GBM detection DATE: 13/05/04 19:49:10 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 07:32:03.39 UT on 04 May 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130504B (trigger 389345526/ 130504314). The on-ground calculated location, using the GBM trigger data, is RA = 353.5, DEC = -5.6 (J2000 degrees, equivalent to 23 h 34 m, -05 d 34'), with an uncertainty of 1 degree (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 57 degrees. Moreover, this burst was bright enough to result in a Fermi spacecraft autonomous rapid repoint (ARR) maneuver. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of a single spike with a duration (T90) of about 0.4 s (50-300 keV). The time-averaged spectrum from T0-0.064 s to T0+0.448 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.42 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 1300 (+80/-70)keV. The event fluence (10-1000 keV) in this time interval is (6.01 +/- 0.14)E-06 erg/cm^2. The 0.064-sec peak photon flux measured starting from T0+0.32 s in the 10-1000 keV band is 40 +/- 2 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 1300 +/-80 keV, alpha = -0.42 +/-0.04 and beta = -3.4 (+0.4/-0.9). The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14561 SUBJECT: IPN Triangulation of GRB 130504B DATE: 13/05/04 22:39:03 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R. Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, K. Hurley and J. Goldsten, on behalf of the MESSENGER NS GRB team, V. Connaughton, M. Briggs, and C. Meegan, on behalf of the Fermi GBM team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and S. Barthelmy, J. Cummings, N. Gehrels, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, report: The short-duration, hard spectrum, intense GRB 130504B (von Kienlin et al., GCN Circ. 14560) has been observed by Fermi GBM, INTEGRAL (SPI-ACS), Konus-Wind, Swift (BAT), and MESSENGER (GRNS), so far, at about 27123 s UT (07:32:03). The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 347.952 (23h 11m 49s) -5.739 ( -5d 44' 20") Corners: 347.658 (23h 10m 38s) -5.056 ( -5d 03' 20") 348.087 (23h 12m 21s) -6.133 ( -6d 07' 58") 348.256 (23h 13m 01s) -6.420 ( -6d 25' 10") 347.821 (23h 11m 17s) -5.345 ( -5d 20' 41") --------------------------------------------- The error box area is 196 sq. arcmin, and its maximum dimension is 1.5 deg (the minimum one is 2.9 arcmin). The Sun distance was 57 deg. This box can be improved. The center of the GBM location (von Kienlin, GCN Circ. 14560) is 5.6 deg from the center of the IPN box. A triangulation map will be posted at http://www.ioffe.ru/LEA/GRBs/GRB130504_T27119/IPN/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14562 SUBJECT: GRB 130504A: MITSuME Okayama upper limits DATE: 13/05/05 02:16:31 GMT FROM: Daisuke Kuroda at OAO/NAOJ D. Kuroda, K. Yanagisawa, Y. Shimizu, H. Toda (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 130504A (Cummings et al., GCNC 14551) with the optical three color (g', Rc and Ic) CCD camera attached to the MITSuME 50cm telescope of Okayama Astrophysical Observatory. The observation started on 2013-05-04 15:09:24 UT (~13.1 h after the burst). We did not find any new point source within the enhanced XRT circle (D'Avanzo et al., GCNC 14558) in all the three bands. Photometric results of the OT are listed below. We used GSC2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.58630 16:09:50 6360.0 >19.9 >19.7 >18.6 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14564 SUBJECT: GRB 130504A: IAC80 optical candidate DATE: 13/05/05 08:38:59 GMT FROM: Javier Gorosabel at IAA-CSIC J. Gorosabel (IAA-CSIC/UPV-EHU), A. de Ugarte Postigo (IAA-CSIC/DARK-NBI), J.C. Tello (IAA-CSIC), A.J. Castro-Tirado (IAA-CSIC), J. Cepa (IAC), D. Jimenez-Mejias (IAC), J.L. Doreste Caballero (HGT), D. Hernandez Ojados (SECAT), R. Sanchez-Ramirez (IAA-CSIC), report on behalf of a larger collaboration: We observed the GRB 130504A field (BAT trigger 555096; Cummings et al. GCN 14551) with the 0.82m IAC80 telescope. The data were acquired in the I-band. The observations started at 02:22:30.6 UT (~17 min post burst) and lasted ~1.5 hours. An object, coincident with the enhanced XRT position (D'Avanzo et al. 14558), shows a clear fading in our images. The optical candidate is placed at RA(J2000)=18:09:49.44, DEC(J2000)=-16:18:48.0 with a Vega magnitude of I=18.1 (against USNO B1.0) in our first images. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14565 SUBJECT: Konus-Wind observation of GRB 130504B DATE: 13/05/05 09:20:24 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The short-duration hard GRB 130504B (Fermi-GBM detection: von Kienlin, GCN 14560; IPN triangulation: Golenetskii et al., GCN 14561) triggered Konus-Wind at T0=27119.723s UT (07:31:59.723) The light curve shows a double-peaked structure from ~T0-0.064 s to ~T0+0.368s. The total duration of the burst is ~0.430 s The emission is seen up to ~8 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130504_T27119/ As observed by Konus-Wind, the burst had a fluence of (9.3 ± 0.9)x10-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.320s, of (5.0 ± 0.9)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 15 MeV range by the cutoff power law with the following model parameters: the photon index alpha = -0.50 ± 0.13, the peak energy Ep = 980 ± 125 keV, chi2 = 40/36 dof. All the quoted results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14574 SUBJECT: GRB 130504C: Fermi-LAT detection of a burst DATE: 13/05/05 16:40:11 GMT FROM: Daniel Kocevski at SLAC D. Kocevski (NASA/GSFC), M. Ohno (Hiroshima U.), J. Racusin (NASA/GSFC), G. Vianello (Stanford), V. Vasileiou (LUPM), and E. Troja (CRESST) report on behalf of the Fermi-LAT team: At 23:30:15 UT on 04 May 2013, Fermi LAT detected high energy emission from GRB 130504C, which was also detected by Fermi-GBM (trigger 389402940 / 130504979). The GBM detection triggered an autonomous repoint of the spacecraft. The best LAT on-ground location is found to be RA=91.715, DEC=3.846 (J2000) with an error radius of 0.155 deg (68% containment, statistical error only). The burst was about 40 deg from the LAT boresight at the time of the trigger and the spacecraft slew brought the source within the LAT field of view for the next 2200 seconds. The data from the Fermi LAT show long lasting emission with >70 photons above 100 MeV observed out to 1000s seconds with a TS of >70. Multi-peaked emission lasting roughly 40 seconds can be seen using the non-standard LAT Low Energy (LLE) with a significance of ~26 sigma. The highest energy LAT photon has an energy of ~5 GeV arriving 251 seconds after the trigger. A Swift TOO request has been submitted. A GBM circular is forthcoming. The Fermi LAT point of contact for this burst is Daniel Kocevski (daniel.kocevski@nasa.gov). The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. Daniel Kocevski NASA Goddard Space Flight Center www.kocevski.com 510.316.3208 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14583 SUBJECT: GRB 130504C: Fermi GBM detection DATE: 13/05/05 23:54:40 GMT FROM: Michael Burgess at UAH J. Michael Burgess (UAH), Valerie Connaughton (UAH) and Shaolin Xiong (UAH) report on behalf of the Fermi GBM Team: "At 23:28:57.518 UT on 04 May 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130504C (trigger 389402940 / 130504978). High peak flux from the GRB caused GBM to issue a repoint request that reoriented the satellite to place the GRB near the LAT boresight for 2.5 hours, subject to Earth limb contraints. The on-ground calculated location, using the GBM trigger data, is RA = 90.71, DEC = 4.45 (J2000 degrees, equivalent to 06 h 02 m, 4 d 27 '), with an uncertainty of 1.0 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). This location is consistent with the LAT location. The angle from the Fermi LAT boresight is 47 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve consists of about 5 peaks associated with the GRB and 1 peak associated with a solar flare about 100 seconds prior to T0. The duration (T90) of the GRB is about 74 s (50-300 keV). The time-averaged spectrum from T0-2.0 s to T0+120.0 s is adequately fit by a Band function with Epeak = 637 +/- 34 keV, alpha = -1.23 +/- 0.01, and beta = -2.28 +/- 0.08 The event fluence (10-1000 keV) in this time interval is (1.34 +/- 0.01)E-04 erg/cm^2. The 1-sec peak photon flux measured starting from T0+30.8 s in the 10-1000 keV band is 43 +/- 0.5 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14584 SUBJECT: GRB 130504C: Swift-XRT observations DATE: 13/05/06 00:33:18 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo, A. Melandri (INAF-OAB) report on behalf of the Swift team: We have analysed 1.3 ks of Swift-XRT data for the Fermi 130504C (Kocevski GCN Circ. 14574; Burgess et al. GCN Circ. 14583), from 65.6 ks to 70.1 ks after the LAT trigger. The data are all in Photon Counting (PC) mode. We detect an uncatalogued X-ray source inside the LAT error circle (Kocevski GCN Circ. 14574), at the following position: RA, Dec=91.63047, 3.83388 which is equivalent to: RA (J2000): 06 06 31.3 Dec (J2000): +03 50 01.96 with an uncertainty of 4.8 arcsec (radius, 90% confidence). The count rate at this position is (4.4 +/- 0.7) x 10^-2 cts/s. At the present stage, it is not possible to determine whether the source is fading. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14587 SUBJECT: Konus-Wind observation of GRB 130504C DATE: 13/05/06 11:08:40 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The long-duration intense GRB 130504C (Fermi-LAT detection: Kocevski et al., GCN 14574; Fermi-GBM detection: Burgess et al., GCN 14583) triggered Konus-Wind at T0=84544.491s UT (23:29:04.491) The light curve shows multiple partly overlapped peaks from ~T0-15 s to ~T0+105s. The emission is seen up to 12 MeV. A possible hard precursor is seen in the 360-1400 keV light curve at ~T0-50s, but its attribution to GRB 130504C is yet unclear. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130504_T84544/ As observed by Konus-Wind, the burst had a fluence of (2.0 ± 0.1)x10-4 erg/cm2, and a 64-ms peak flux, measured from T0+21.440s, of (2.6 ± 0.2)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+105.216 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -1.32 ± 0.04, the high energy photon index beta = -2.15 ± 0.1, the peak energy Ep = 452 ± 49 keV, chi2 = 110/97 dof. The spectrum at the maximum count rate (measured from T0+21.248 to T0+23.296 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.74 ± 0.12, the high energy photon index beta = -1.93 ± 0.06, the peak energy Ep = 251 ± 38 keV, chi2 = 61/66 dof. All the quoted results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14588 SUBJECT: GRB 130504C: further Swift-XRT observations DATE: 13/05/06 14:14:28 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo, A. Melandri (INAF-OAB), P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: We have analysed 7.7 ks of XRT data for the Fermi-LAT-detected burst: GRB 130504C, from 65.6 ks to 93.3 ks after the Fermi-LAT trigger. The data are entirely in Photon Counting (PC) mode. The X-ray source reported by D'Avanzo et al. (GCN Circ. 14584) displays behaviour consistent with fading. We propose it as the X-ray afterglow of GRB 130504C. The refined XRT position is RA, Dec = 91.63038, +3.8339 which is equivalent to: RA (J2000): 06 06 31.29 Dec(J2000): +03 50 02.0 with an uncertainty of 3.6 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=1.3 (+/-1.0). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.8 (+/-0.3). The best-fitting absorption column is 5.1 (+2.0, -1.6) x 10^21 cm^-2, in excess of the Galactic value of 2.5 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 5.0 x 10^-11 (7.9 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 5.1 (+2.0, -1.6) x 10^21 cm^-2 Galactic foreground: 2.5 x 10^21 cm^-2 Excess significance: 2.7 sigma Photon index: 1.8 (+/-0.3) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020267. This circular is an official product of the Swift-XRT team. [GCN OPS NOTE(06may13): Per author's request, the extra "further" was removed from the ubject-line.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14600 SUBJECT: GRB 130504B: Suzaku WAM observation of the prompt emission DATE: 13/05/08 04:30:55 GMT FROM: Makoto Tashiro at Saitama U/Swift T. Yasuda, M. Tashiro, Y. Terada, Y. Ishida, H. Ueno, S. Sugimoto (Saitama U.), M. Ohno, K. Takaki, T. Kawano, R. Nakamura, S. Furui, Y. Fukazawa (Hiroshima U.), M. Yamauchi, N. Ohmori, M. Akiyama (Univ. of Miyazaki), K. Yamaoka (Nagoya U.), S. Sugita (Ehime U.), Y. E. Nakagawa, M. Kokubun, T. Takahashi (ISAS/JAXA), W. Iwakiri (RIKEN), Y. Hanabata (ICRR), Y. Urata (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo) on behalf of the Suzaku WAM team, report: The bright, short, IPN localized GRB 130504B (GCN 14560; von Kienlin et al., GCN 14561; Golenetskii et al.) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 07:32:03.063 UT (=T0). The observed light curve shows a double-peaked structure starting at T0+0.25 s, ending at T0+0.75 s with a duration (T90) of about 0.38 seconds. The fluence in 100 - 1000 keV was 4.97(+0.15/-0.30) x10^-6 erg/cm^2. The 1-s peak flux measured was 7.60 (+0.28/-0.54) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0 to T0+1 s is well fitted by a power-law with exponential cutoff model: dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha 0.41 (+0.20/-0.22), and Epeak 1321 (+139/-129) keV (chi^2/d.o.f. = 35.1/24). All the quoted errors are at statistical 90% confidence level. The light curves for this burst are available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14603 SUBJECT: GRB 130504C: Swift-XRT afterglow confirmation DATE: 13/05/08 15:13:43 GMT FROM: Paolo D'Avanzo at INAF-OAB P. D'Avanzo (INAF-OAB), A.Y. Lien (NASA-GSFC), P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: We have analysed 12.3 ks of XRT data for the Fermi-LAT-detected burst GRB 130504C (Kocevski et al. GCn Circ 14574), from 65.6 ks to 278.7 ks after the Fermi-LAT trigger. The data are entirely in Photon Counting (PC) mode. The X-ray source reported by D'Avanzo et al. (GCN Circ. 14584, 14588) displays a fading behaviour. The overall light curve can be modelled with a power-law decay with a decay index of alpha=1.39 (+0.32, -0.25). We confirm it as the X-ray afterglow of GRB 130504C. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020267.