//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14874 SUBJECT: GRB 130612A: Swift detection of a burst with an optical counterpart DATE: 13/06/12 03:44:00 GMT FROM: David Palmer at LANL J. L. Racusin (NASA/GSFC), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), J. A. Kennea (PSU), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), C. Pagani (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 03:22:22 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130612A (trigger=557976). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 259.804, +16.706 which is RA(J2000) = 17h 19m 13s Dec(J2000) = +16d 42' 21" 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 5 sec. The peak count rate was ~1000 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 03:23:49.1 UT, 87.0 seconds after the BAT trigger. The position determined from promptly downlinked data differs significantly from the on-board position, suggesting that the XRT may have centroided on a cosmic ray; the initial XRT position notice should be treated with caution. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 259.7940, 16.7205 which is equivalent to: RA(J2000) = 17h 19m 10.55s Dec(J2000) = +16d 43' 13.9" with an uncertainty of 2.7 arcseconds (radius, 90% containment). This location is 62 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. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (5.96 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 7.8 (+9.63/-6.58) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 91 seconds with the White filter starting 94 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 17:19:10.59 = 259.79411 DEC(J2000) = +16:43:11.7 = 16.71991 with a 90%-confidence error radius of about 0.64 arc sec. This position is 2.3 arc sec. from the center of the XRT error circle. The estimated magnitude is 18.80 with a 1-sigma error of about 0.15. No correction has been made for the expected extinction corresponding to E(B-V) of 0.08. Burst Advocate for this burst is J. L. Racusin (judith.racusin 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/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14875 SUBJECT: GRB 130612A: Liverpool Telescope Afterglow detection DATE: 13/06/12 03:58:00 GMT FROM: Andrea Melandri at INAF-OAB A. Melandri (INAF-OAB), C.G. Mundell (LJMU) and A. Gomboc (U. Ljubljana) )report: The 2-m Liverpool Telescope robotically followed up GRB130612A (Swift trigger 557976, Racusin et al., GCN 14874) ~16 min after the GRB trigger time observing with SLOAN-gri filters. The automatic LT-TRAP procedure detected an uncatalogued fading source candidate at: RA = 17:19:10.57 Dec = +16:43:11.6 (J2000) with magnitude R~18.9 mag (vs USNOB1) ~16 min after the burst trigger. The object is clearly fading in all filters. Observations and analysis are ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14876 SUBJECT: GRB 130612A: PAIRITEL NIR Afterglow Observations DATE: 13/06/12 04:07:12 GMT FROM: Adam Morgan at U.C. Berkeley A. N. Morgan (UC Berkeley) reports: We observed the field of GRB 130612A (Racusin et al., GCN 14874) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2013-Jun-12 03h29m25s UT, 6.65 minutes after the Swift Trigger. In mosaics (consisting of 48 ~8 second images for a total effective exposure time of 6.3 minutes) taken simultaneously in the J, H, and Ks filters, we detect the optical afterglow (Racusin et al., GCN 14874; Melandri et al., GCN 14875). The preliminary K-band reduction is corrupted. The observations quoted below began at 3:32 UT, ~9.5 minutes after the Swift trigger, after an automatic pointing reset by our telescope. The preliminary photometry yields: post burst t_mid (m) exp.(m) filt mag m_err 14.6 6.3 J 17.26 0.12 14.6 6.3 H 16.78 0.15 Observations are ongoing. All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14877 SUBJECT: GRB 130612A: Skynet/PROMPT detection of the optical afterglow DATE: 13/06/12 04:36:09 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet A. Trotter, J. Haislip, D. Reichart, A. LaCluyze, T. Berger, M. Carroll, H. T. Cromartie, R. Egger, A. Foster, C. Foster, N. Frank, K. Ivarsen, D. James, M. Maples, J. Moore, M. Nysewander, E. Speckhard, P. Taylor and J. A. Crain report Skynet observed the Swift XRT localization of the field of GRB 130612A (Racusin et al., GCN 14874, Swift trigger #557976), beginning at 2013-06-12, 3:23:27 UT (t=70s post-trigger) using three 16" telescopes of the PROMPT array at Cerro Tololo, Chile. We detect a fading afterglow in the B, V and I bands at a position (J2000.0) RA: 17:19:10.6 Dec: 16:43:11.6, consistent with the detections of Racusin et al. (GCN 14874), Melandri, Mundell & Gomboc (GCN 14875), and Morgan (GCN 14876). A preliminary light curve is at: http://www.skynet.unc.edu/grb/grb130612a.png Preliminary photometry is calibrated to 5 NOMAD/USNO B1.0 stars in the field, and magnitudes are in the Vega system. Skynet observations are ongoing. [GCN OPS NOTE(12jun13): Per author's request, the typo in JH's name was corrected.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14878 SUBJECT: GRB 130612A: NOT optical observations DATE: 13/06/12 04:50:12 GMT FROM: Dong Xu at DARK/NBI P. Jakobsson (U. Iceland), D. Xu (DARK/NBI), D. Malesani (DARK/NBI), K. Mikkelsen (U. Oslo), N. Aghanim (CNRS & Universite Paris-Sud Orsay) report on behalf of a larger collaboration: We observed the optical afterglow of GRB 130612A (Racusin et al., GCN 14874; Melandri et al., GCN 14875) using the 2.5-m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. We obtained 4x300s R-band images with a median time 04:06:09 UT on 12 June 2013 (i.e. 0.73 hr after the burst). The optical afterglow was clearly detected with R ~ 20.3 mag calibrated with nearby stars in the USNO B1 catalog. [GCN OPS NOTE(12jun13): Per author's request, NA was added to the author list.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14879 SUBJECT: GRB 130612A: P60 Observations DATE: 13/06/12 04:56:01 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (NASA/GSFC) and D. A. Perley report on behalf of a larger collaboration: We have imaged the field of the Swift GRB 130612A (Racusin et al., GCN 14874) with the robotic Palomar 60 inch telescope. Observations consist of individual 120 s frames in the g', r', i', and z' filters beginning at 4:20 UT on 2013 June 12 (58 minutes after the Swift trigger). The optical afterglow is detected in individual frames in all four filters. Using several nearby point sources from the USNO-B1 catalog for reference, we measure a magnitude of R = 20.8 at this time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14880 SUBJECT: GRB 130612A: RATIR Optical Observations DATE: 13/06/12 05:11:03 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB) J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of GRB 130612A (Racusin, et al., GCN Circular 14874) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2013/06 12.16 to 2013/06 12.20 UTC (0.40 to 1.31 hours after the BAT trigger), obtaining a total of 0.71 hours exposure in the r' and i' bands. For a source within the Swift-XRT error circle, in comparison with USNO-B1 and 2MASS, we obtain the following detections: r' 21.23 ± 0.07 i' 21.05 ± 0.06 These magnitudes are in the AB system and not corrected for Galactic extinction in the direction of the GRB. The position of the source is consistent with the UVOT afterglow position Racusin, et al., GCN Circular 14874). The afterglow appears to have faded considerably since the earlier observations reported by Melandri et al. (GCN Circular 14875), and Jakobsson et al. (GCN Circular 14878). We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14881 SUBJECT: GRB130612A OSN I-band observations DATE: 13/06/12 05:40:32 GMT FROM: Juan Carlos Tello at IAA-CSIC J.C.Tello, V. Casanova (IAA-CSIC), J. Gorosabel (UPV-EHU, IAA-CSIC), A.J.Castro-Tirado, R. Sanchez-Ramirez, M. Jelinek (IAA-CSIC), on behalf of a larger collaboration report: We observed the field of GRB130612A (Racusin et al., GCNC 14874) in the I-band with the 1.5m telescope in Sierra Nevada, Granada, Spain. Combining 33x10s images (for a total 330 seconds of exposure) spanning from 03h38m (16 minutes after the burst) to 03h55m (with a mean time of 25 minutes after the burst) we observe the reported afterglow (Melandri et al., GCNC 14875) with a magnitude of I(Vega) ~ 18.7 when compared to the USNO B1.0 catalog. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14882 SUBJECT: GRB 130612A: VLT/X-shooter redshift DATE: 13/06/12 06:18:45 GMT FROM: Nial Tanvir at U.Leicester N. R. Tanvir (U. Leicester), K. Wiersema (U. Leicester), D. Xu (DARK/NBI), J. P. U. Fynbo (DARK/NBI) report for a larger collaboration: We observed the afterglow of GRB 130612A (Racusin et al. GCN 14874) with VLT/X-shooter, beginning at 2013-06-12 04:28 UT, about 66 mins after the burst. Preliminary analysis of the spectrum reveals absorption lines of FeII 2261, 2374, 2344, 2383, 2600, 2587, 2600, 2607, MnII 2577, MgII 2796/2803 and MgI 2852 at a common redshift of z=2.006. This is consistent with a break seen in the UVB arm spectrum due to a damped Lyman-alpha feature at ~3650 A. We therefore propose this to be the redshift of the GRB. We thank the staff at Paranal, particularly Christophe Martayan, for obtaining these observations. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14883 SUBJECT: GRB 130612A: TAROT La Silla observatory optical observations DATE: 13/06/12 08:53:25 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A. (IRAP-CNRS-OMP), Gendre B. (IRAP-CNRS-OMP), Boer M., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 130612A detected by SWIFT (trigger 557976) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 34.4s after the GRB trigger (14.5s after the notice). The elevation of the field increased from 40 degrees above horizon and weather conditions were excellents. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We detect the OT detected by Racusin et al. (GCNC 14874), Melandri et al. (GCNC 14875). Photometry is done using NOMAD-1 1067-0303513 (R.A.=259.7905194 Dec=+16.7139250 R=16.9) as reference star. At the start of the trail t0+34.4s R=16.9 At the end of the trail t0+94.4s R=17.5 Next images are acquired in tracking mode. The afterglow is visible more than 30 minutes after the burst. One of the last measurement is: From t0+1466s to t0+2113s R=19.9 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14884 SUBJECT: GRB 130612A: Enhanced Swift-XRT position DATE: 13/06/12 11:57:53 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 501 s of XRT Photon Counting mode data and 1 UVOT images for GRB 130612A, 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 = 259.79393, +16.71971 which is equivalent to: RA (J2000): 17h 19m 10.54s Dec (J2000): +16d 43' 11.0" 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: 14885 SUBJECT: GRB 130612A: Zadko observatory - Gingin optical observations DATE: 13/06/12 13:55:06 GMT FROM: Alain Klotz at IRAP-CNRS-OMP A. Klotz (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR), D. Coward (UWA), B. Gendre (IRAP-CNRS-OMP), M. Boer, K. Siellez, H. Dereli , O. Bardho (UNS-CNRS-OCA), A. Williams (PO-UWA), R. Martin (PO-UWA) report: We imaged the field of GRB 130612A detected by SWIFT (trigger 557976) with the Zadko robotic telescope (D=100cm) located at the observatory - Gingin, Australia. The observations started 9.3h after the GRB trigger. The elevation of the field increased from 20 degrees above horizon and weather conditions were good. We have not detected the OT detected by Racusin et al. (GCNC 14874), Melandri et al. (GCNC 14875): From t0+9.3h to t0+10.2h Rlim = 21.2 Magnitudes are not corrected for galactic dust extinction. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14886 SUBJECT: GRB 130612A: Swift-XRT refined Analysis DATE: 13/06/12 15:44:03 GMT FROM: Phil Evans at U of Leicester G. Stratta (ASDC), P. D'Avanzo (INAF-OAB), M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester), J.P. Osborne (U. Leicester), V. D'Elia (ASDC) and J.L. Racusin report on behalf of the Swift-XRT team: We have analysed 11 ks of XRT data for GRB 130612A (Racusin et al. GCN Circ. 14874), from 74 s to 30.7 ks after the BAT trigger. The data comprise 233 s in Windowed Timing (WT) mode (the first 9 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 14884). The light curve can be modelled with a power-law decay with a decay index of alpha=0.96 (+0.09, -0.08). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.19 (+0.28, -0.26). The best-fitting absorption column is 7.7 (+6.6, -5.5) x 10^21 cm^-2, at a redshift of 2.006, in addition to the Galactic value of 6.0 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 3.3 x 10^-11 (4.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 6.0 x 10^20 cm^-2 Intrinsic column: 7.7 (+6.6, -5.5) x 10^21 cm^-2 at z=2.006 Photon index: 2.19 (+0.28, -0.26) If the light curve continues to decay with a power-law decay index of 0.96, the count rate at T+24 hours will be 1.8 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.1 x 10^-14 (8.7 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00557976. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14887 SUBJECT: GRB 130612A: Swift/UVOT Detection DATE: 13/06/12 17:42:22 GMT FROM: Alice Breeveld at MSSL-UCL A. A. Breeveld (MSSL-UCL) and J. L. Racusin (NASA/GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 130612A 94 s after the BAT trigger (Racusin et al., GCN Circ. 14874). A fading source consistent with the XRT position (Beardmore et al. GCN Circ. 14884) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 17:19:10.58 = 259.79408 (deg.) Dec (J2000) = +16:43:11.9 = 16.71996 (deg.) with an estimated uncertainty of 0.53 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 94 185 89 18.97 ± 0.07 v 763 7763 549 >20.6 b 688 13692 1307 >21.3 u 664 1655 117 19.68 ± 0.24 w1 639 18651 2143 >21.6 m2 614 17743 1406 >21.6 w2 738 7559 549 >21.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.08 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14889 SUBJECT: GRB 130612A: MITSuME Okayama upper limits DATE: 13/06/12 19:00:02 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 MITSuME and OISTER collaboration: We observed the field of GRB 130612A (Racusin et al., GCNC 14874) 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 2013-06-12 11:27:22 UT (~8.08 h after the burst). We could not detect the previously reported afterglow (Racusin et al., GCNC 14874; Melandri et al., GCNC 14875) in all the three bands. Three sigma upper limits of the OT are listed below. We used GSC 2.3 catalog for flux calibration. #T0+[day] MID-UT T-EXP[sec] g' Rc Ic ----------------------------------------------------- 0.43348 13:46:34 7800.0 >20.2 >20.2 >19.4 ----------------------------------------------------- T0+ : Elapsed time after the burst [day] T-EXP: Total Exposure time [sec] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14890 SUBJECT: GRB 130612A: ISON-NM optical observations DATE: 13/06/12 21:13:30 GMT FROM: Alexei Pozanenko at IKI, Moscow L. Elenin (KIAM), A. Volnova (IKI), V. Savanevych (KNURE), A. Bryukhovetskiy (NSFCTC), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed of the field of the Swift GRB 130612A (Racusin et al., GCN 14874) with 0.45-m telescope of ISON-NM observatory starting on June, 12 (UT) 04:06:14. Series of 30 s exposures were obtained in clear filter. In the combined images we detected afterglow (Racusin et al., GCN 14874; Melandri et al., GCN14875) in coordinates (J2000) 17 19 10.63 +16 43 12.0. Preliminary photometry is based on the USNO-B1.0 1067-0299350 star assuming R=18.92. UT start, T0+ Filter Exposure, OT mid,d s 2013-06-12T04:06:14 0.0305 none 30*30 20.75 +/- 0.15 2013-06-12T04:29:28 0.0466 none 30*30 21.25 +/- 0.20 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14894 SUBJECT: GRB 130612A: iTelescope T21 optical observations DATE: 13/06/14 02:27:46 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report: We have detected GRB 130612A optical afterglow at iTelescope observatory T21 (Mayhill, New Mexico) 0.43m/6.8 astrograph and FLI-PL6303E CCD camera. One unfiltered image with 300 sec exposure time was made. The afterglow was detected at following position RA 17:19:10.55 and DEC +16:43:11.9 The following magnitude was obtained from the observation using NOMAD1 1067-0303513 (R=16.900) as the comparison: Tmid(sec)+T0 Filter Exp. time Mag Mag err. 1133 unfiltered 300 19.19CR 0.39 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14896 SUBJECT: GRB 130612A: Fermi GBM observation DATE: 13/06/14 18:06:06 GMT FROM: Gerard Fitzpatrick at UCD G. Fitzpatrick (UCD) reports on behalf of the Fermi GBM Team: At 03:22:23.36 UT on 12 June 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130612A (trigger 392700146/130612141) which was also detected by the Swift/BAT (Racusin et al., GCN Circ. 14874). The GBM on-ground location is consistent with the Swift position. The GBM light curve consists of a single peak with a duration (T90) of about 5.6 s (50-300 keV). The time-averaged spectrum from T0-2.6 s to T0+2.3 s is adequately fit by a power law function with an exponential high-energy cutoff. The power law index is -1.3 +/- 0.3 and the cutoff energy, parameterized as Epeak, is 61.9 +/- 10.5 keV. The event fluence (10-1000 keV) in this time interval is (5.7 +/- 0.6)E-07 erg/cm^2. The 1-sec peak photon flux measured starting from T0-1.8 s in the 10-1000 keV band is 4.1 +/- 0.2 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: 14914 SUBJECT: GRB 130612A: Continued Skynet/PROMPT/GORT/DSO observations DATE: 13/06/17 23:14:09 GMT FROM: Adam S. Trotter at UNC-Chapel Hill/PROMPT/Skynet M. Carroll, A. Trotter, J. Hailslip, D. Reichart, A. LaCluyze, K. McLin, L. Cominsky, A. Smith, D. Caton, L. Hawkins, T. Berger, H. T. Cromartie, R. Egger, A. Foster, C. Foster, N. Frank, K. Ivarsen, D. James, M. Maples, J. Moore, M. Nysewander, E. Speckhard, P. Taylor and J. A. Crain report Skynet observed the Swift XRT localization of the field of GRB 130612A (Racusin et al., GCN 14874, Swift trigger #557976), beginning at 2013-06-12, 3:23:27 UT (t=70s post-trigger), and continuing until t~5h, using three 16" telescopes of the PROMPT array at Cerro Tololo, Chile (BVI bands), the 14" GLAST Optical Robotic Telescope (GORT) at the Hume Observatory in California (RcIc bands), and the 14" telescope at the Appalachian State University Dark Sky Observatory (DSO-14) in Pisgah National Forest, North Carolina (RI bands). It took a total of ~500 exposures ranging from 10s to 160s. As we reported in Trotter et al. (GCN 14877), we detect a fading afterglow in the B, V and I bands out to t~1h at a position consistent with the detections of Racusin et al. (GCN 14874), Melandri, Mundell & Gomboc (GCN 14875), and Morgan (GCN 14876). In stacked images we obtain further detections in the V band at t=3.2h, and in the I band at t=1.5h and 1.9h. The afterglow fades with an approximate temporal index alpha~-0.9. A preliminary light curve is at: http://skynet.unc.edu/grb/grb130612a_2.png Magnitudes are in the Vega system, calibrated to 4 APASS stars in the field. No correction has been applied for the expected line-of-sight Milky Way extinction E(B-V)=0.076 (Schlegel et al. 1998). No further Skynet observations are scheduled. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14916 SUBJECT: GRB 130612A: Swift-BAT refined analysis DATE: 13/06/19 22:01:54 GMT FROM: Craig Markwardt at NASA/GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), T. Sakamoto (AGU), on behalf of the Swift-BAT team: Using the data set from T-25 to T+100 sec from the recent telemetry downlink, we report further analysis of BAT GRB 130612A (trigger #557976) (Racusin, et al., GCN Circ. 14874). The BAT ground-calculated position is RA, Dec = 259.771, 16.729 deg which is RA(J2000) = 17h 19m 05.0s Dec(J2000) = +16d 43' 44.7" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 34%. The mask weighted light curve shows a single FRED-like profile with a rise time of about 1 sec near T+0sec and a gradual decay time with e-folding time of about 3 sec. This burst was detected as the Swift spacecraft was entering the South Atlantic Anomaly region, and the raw background counting rate was ramping upward. The mask weighted light curve does not have a clean background level, so estimating the T90 is difficult. If we restrict the analysis to the time range T-25 to T+100, we estimate T90 (15-350 keV) to be 4.0 +/- 1.4 sec. However, we cannot rule out the possibility of a faint extended emission tail to approximately T+100 (in which case T90 is 110 +/- 60 sec). The time-averaged spectrum from T-0.83 to T+3.17 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.14 +- 1.71, and Epeak of 36.4 +- 7.6 keV (chi squared 36 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 2.3 +- 0.5 x 10^-7 erg/cm2 and the 1-sec peak flux measured from T+0.17 sec in the 15-150 keV band is 1.7 +- 0.3 ph/cm2/sec. A fit to a simple power law gives a photon index of 2.06 +- 0.25 (chi squared 44 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/557976/BA/