//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14282 SUBJECT: GRB 130310A: Fermi-LAT detection and localization DATE: 13/03/11 07:36:13 GMT FROM: Sylvain Guiriec at UAH S. Guiriec (NASA/GSFC/NPP), G. Vianello (Stanford) and M. Ohno (Hiroshima U.) report on behalf of the Fermi-LAT team: The Fermi Large Area Telescope (LAT) detected emission from GRB 130310A (GBM trigger 130310840/384638984) at approximately 20:09:44 UT on March 10th, 2013, about 3s after Fermi-GBM trigger time. The burst location was outside the LAT nominal field of view, at an angle of ~79 degrees from the LAT boresight, and ~50 degrees from the Zenith. Using the non-standard LAT Low Energy (LLE) data selection, featuring a large effective area and a larger field of view below 100 MeV but a much larger PSF with respect to the standard classes, we clearly detect the prompt emission of the GRB (significance > 10 sigma above the background). With this selection and in this energy range the GRB shows a single FRED-like pulse, peaking ~3 s after the GBM trigger in good coincidence with the peak of the GBM emission. The high peak flux of the burst triggered an Autonomous Repointing Request (ARR) starting about 50s after the trigger time, which placed the GRB within the LAT nominal field of view for standard data classes (~65 deg) approximately 200 s after the trigger. Using the P7SOURCE_V6 class we detect ~18 photons between 100 MeV and 3 GeV in the time interval 200 s - 800 s from the trigger, clearly clustered in a point source ~4.8 deg away from the best GBM position and with a significance larger than 5 sigma. Our best localization is: R.A., Dec = 142.34, -17.23 (J2000) 90 % containment radius (statistical only) = 0.45 deg. A GBM circular on GRB 130310A is forthcoming. The Fermi LAT point of contact for this burst is Sylvain Guiriec (sylvain.guiriec@nasa.gov) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14283 SUBJECT: GRB 130310A: Fermi GBM detection DATE: 13/03/11 08:48:12 GMT FROM: Shaolin Xiong at UAH Shaolin Xiong (UAH) and Vandiver Chaplin (UAH) report on behalf of the Fermi GBM Team: "At 20:09:41.50 UT on 10 March 2013, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 130310A (trigger 384638984 / 130310840), which was also detected by the Fermi/LAT (Guiriec et al. 2013, GCN 14282) The GBM on-ground location is consistent with the LAT position. At the time of triggering the angle from the Fermi LAT boresight was 79 degrees. GBM generated a Autonomous Repointing Request (ARR) due to the high peak flux of this GRB, causing Fermi to reorient so that the LAT could better observe this GRB. The GBM light curve consists of a precursor and a FRED pulse with a duration (T90) of about 2.4 s (50-300 keV). The time-averaged spectrum from T0+4.1 s to T0+5.0 s is adequately fit by a Band function with Epeak = 2.1 +/- 0.2 MeV, alpha = -1.01 +/- 0.02, and beta = -2.27 +/- 0.1. The event fluence (10-1000 keV) in this time interval is (1.4 +/- 0.02)E-5 erg/cm^2. The 0.064 sec peak photon flux measured starting from T0+4.1 s in the 10-1000 keV band is 170 +/- 3 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: 14284 SUBJECT: IPN triangulation of GRB 130310A DATE: 13/03/11 13:10:43 GMT FROM: Dmitry Svinkin at Ioffe Institute 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 MESSENGER GRNS GRB team, I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, V. Connaughton, M. Briggs, and C. Meegan, on behalf of the Fermi GBM team, K. Yamaoka, M. Ohno, Y. Hanabata, Y. Fukazawa, T. Takahashi, M. Tashiro, Y. Terada, T. Murakami, and K. Makishima on behalf of the Suzaku WAM team, and A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report: The short-duration, hard-spectrum, intense GRB 130310A (Fermi/LAT detection: Guiriec, Vianello, Ohno, GCN 14282; Fermi/GBM detection: Xiong and Chaplin, GCN 14283) has been also observed by Konus-Wind, Suzaku (WAM), INTEGRAL (SPI-ACS), MESSENGER (GRNS), and Mars Odyssey (HEND), so far, at about 72585 s UT (20:09:45). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 141.905 (09h 27m 37s) -17.431 (-17d 25' 53") Corners: 141.722 (09h 26m 53s) -16.780 (-16d 46' 50") 141.801 (09h 27m 12s) -17.435 (-17d 26' 06") 142.093 (09h 28m 22s) -18.072 (-18d 04' 18") 142.008 (09h 28m 02s) -17.428 (-17d 25' 40") --------------------------------------------- The error box area is 465 sq. arcmin, and its maximum dimension is 80 arcmin (the minimum one is 12 arcmin; the minimum annulus width is 11 arcmin). This box can be improved. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB130310_T72588/IPN/ The center of the LAT position (Guiriec, Vianello, Ohno, GCN 14282) is 0.46 deg from the box center. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14285 SUBJECT: Konus-Wind observation of GRB 130310A DATE: 13/03/11 14:14:12 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 hard intense GRB 130310A (Fermi-LAT detection: Guiriec et al., GCN 14282; Fermi-GBM detection: Xiong and Chaplin, GCN 14283 IPN triangulation: Golenetskii et al., GCN 14284) triggered Konus-Wind at T0=72588.897s UT (20:09:48.897) The light curve shows a bright hard FRED-like structure with a total duration of ~3 s. The emission is seen up to 10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130310_T72588/ As observed by Konus-Wind, the burst had a fluence of (3.0 ± 0.3)x10-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.000s, of (3.6 ± 0.2)x10-4 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+8.448 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 = -1.03 ± 0.05, the high energy photon index beta = -1.85 ± 0.15, the peak energy Ep = 855 ± 270 keV, chi2 = 85.8/97 dof. The spectrum at the maximum count rate (measured from T0 to T0+0.064 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 = -0.87 ± 0.13, the high energy photon index beta = -1.62 ± 0.28, the peak energy Ep = 2600 ± 1400 keV, chi2 = 27.9/26 dof. All the quoted results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14288 SUBJECT: Swift XRT observations of GRB 130310A DATE: 13/03/12 03:12:58 GMT FROM: Boris Sbarufatti at INAF-OAB/IASFPA B. Sbarufatti (INAF-OAB/PSU), D. N. Burrows (PSU), J. L. Racusin (NASA/GSFC), C. J. Mountford (U Leicester), N. Gehrels (NASA/GSFC) report on behalf of the Swift team: Swift performed 3 pointings of 1.5 ks each to cover the IPN error box for GRB 130310A (Golenetskii et al., GCN #14284). A single, uncatalogued source is detected at coordinates: RA/Dec (J2000) = 09 27 36.35 -17 06 16.1 RA/Dec (J2000) = 141.901 -17.1044 Error radius (arcsec) = 3.6 (90% confidence level) The source is inside the IPN error box, and 0.44 degrees from the Fermi LAT position (Guiriec et al., GCN #14282), just inside the LAT error circle. The countrate is 7.60E-03 +/- 2.5E-03 c/sec At present is not possible to tell if the source is fading. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14289 SUBJECT: GRB 130310A: optical observations DATE: 13/03/12 08:00:05 GMT FROM: Antonino Cucchiara at UCSC/UCO Lick A. Cucchiara (UCSC/UCO Lick Observatory), S. B. Cenko (UC Berkeley), D. Perley (Caltech) report on behalf of a large collaboration: "On March 12.4 UT we observed the field of the short-hard GRB 130313A (GCN 14282, 14283, 14284, 14285 and 14288) with the Gemini-South telescope equipped with the GMOS camera. We obtained 5x180s exposures, for a total integration time of 15 minutes (T_mid = T0+1.22 days). A snapshot of our imaging campaign can be seen here: https://www.dropbox.com/s/jqt714c44b7ngei/0310A_rband.jpeg We note the presence of two irregular objects (marked as "G1" adn "G2") within the current XRT error circle (3.6 arcsec radius, GCN 14288). The coordinates of this objects are: "G1" RA: 09:27:36.34 (J2000) Dec: -17:06:18.92 (J2000) "G2" RA: 09:27:36.46 (J2000) Dec: -17:06:13.80 (J2000) Using 3 USNO-B1 stars we estimate a preliminary brightness for "G1" of r' = 25.05 +- 0.15 and for "G2" r'=23.80 +- 0.10. At this point the nature of these objects as well as the relation with GRB 130313A afterglow is still uncertain. Further observations are encouraged. We thank the Gemini staff for performing this observations, in particular J. Thomas-Osip" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14290 SUBJECT: Swift XRT RETRACTION of GRB 130310A afterglow detection DATE: 13/03/12 14:44:15 GMT FROM: Boris Sbarufatti at INAF-OAB/IASFPA B. Sbarufatti (INAF-OAB/PSU), D. N. Burrows (PSU), P. E. Evans (U Leicester), E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team: Upon further analysis of the Swift XRT observations of the IPN error box for GRB 130310A (Svinkin et al., GCN #14284) we RETRACT the detection of a candidate afterglow reported by Sbarufatti et al., GCN #14288. Further analysis is ongoing. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14310 SUBJECT: GRB 130310A : Suzaku WAM observation of the prompt emission DATE: 13/03/15 10:55:37 GMT FROM: Masanori Ohno at Hiroshima U T. Kawano, M. Ohno, Y. Hanabata, Y. Tanaka, R. Nakamura, K. Takaki, Y. Fukazawa (Hiroshima U.), A. Sakamoto, M. Tashiro, Y. Terada, W. Iwakiri, T. Yasuda, K. Takahara, M. Asahina, S. Kobayashi, H. Ueno (Saitama U.), M. Akiyama, N. Ohmori, M. Yamauchi (Univ. of Miyazaki), Y. E. Nakagawa (Waseda U.), S. Sugita (Nagoya U.), K. Yamaoka, M. Kokubun, T. Takahashi (ISAS/JAXA), Y. Urata, P. Tsai (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report: The bright short GRB (Fermi-LAT detection ; Guiriec et al., GCN14282; Sbarufatti et al., GCN 14288) triggered by the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 20:09:45 UT (=T0). The observed light curve shows a single peak structure starting at T0 s, ending at T0+1 s with a duration (T90) of about 0.3 seconds. The fluence in 100 - 1000 keV was 7.78 (-1.13, +2.72) x 10^-6 erg/cm^2. The 1-s peak flux measured from T0 s was 14.34(-1.37,+2.30) 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 GRB Band model: the low-energy photon index alpha: -1.13 (-0.25, +0.16), beta : -2.07 (-0.32, +0.19) and the peak energy Epeak: 1000 (-442, +639) keV (chi^2/d.o.f = 43.2/44). All the quoted errors are at statistical 90% confidence level. The light curves for this burst will be available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14316 SUBJECT: Swift XRT observations of GRB 130310A DATE: 13/03/15 22:03:36 GMT FROM: Boris Sbarufatti at INAF-OAB/IASFPA B. Sbarufatti (INAF-OAB/PSU), D. N. Burrows (PSU), P. E. Evans (U Leicester) report on behalf of the Swift XRT team: Swift performed a total of 7 pointings for this burst on March 11th: 4x1ks covering the Fermi LAT error circle (Guiriec et al., GCN #1482) and 3x1.5 ks covering the IPN error box (Golenetskii et al., GCN #14284). We detect a total of 5 sources: # RA DEC Err counts rate(counts/ks) 1 09 28 45.9 -17 18 49.5 7.4" 9 11 (+11/-7) 2 09 29 27.0 -17 30 13.8 6.8" 12 13 (+14/-8) 3 09 28 59.0 -17 00 40.8 5.4" 8 9 (+10/-7) 4 09 27 58.9 -17 12 57.9 8.6" 10 11 (+12/-7) 5 09 27 31.7 -17 08 55.3 11.0" 5 4.7 (+6/-4) The fluxes are computed at the 99% confidence level, following Kraft, Burrows & Nousek (1991). The background level was computed both generally, using the 'background' task of XIMAGE on each pointing, and locally, using the 'sosta' task of XIMAGE, and selecting the highest value. All sources are inside the LAT error circle, but only source #5 is inside the IPN error box. Swift performed another observation in the direction of source #5 on March 13th, with a 3.4 ks exposure. The 99% confidence level upper limit at the position of source #5 is 4.6E-3 counts/s, which does not give strong evidence for fading. No further observations are planned. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 14350 SUBJECT: GRB 130310A: RATIR Observations DATE: 13/03/28 15:50:17 GMT FROM: Nat Butler at Az State U 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), 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 the Fermi-LAT detected GRB 130310A (Guiriec, et al., GCN 14282) 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. Data were taken in the r' and i' channels for a central 9.8 x 7.3 arcmin^2 portion of the IPN error region (Golenetskii, et al., GCN 14284), centered on RA, DEC = 141.90061, -17.10809 (J2000), in 2 epochs, 1.31-1.47 days after the Fermi trigger and 3.31-3.45 days after the Fermi trigger. We reach a limiting magnitude ~24 (AB) in both channels in both epochs. Data were captured in the Z, Y, J, and H bands over a larger field (14.8 x 12.5 arcmin^2), reaching a shallower limit (~22 AB). Of the XRT candidate afterglows (Sbarufatti, et al., GCN 14316), only source #5 is contained in our images. We detect that source in both epochs at a position RA, DEC = 141.881334, -17.147639 (+/-0.5" J2000): Epoch 1: r' = 23.6 +/- 0.1 i' = 23.6 +/- 0.2 Epoch 2: r' = 23.5 +/- 0.1 i' = 23.3 +/- 0.2 These magnitudes are in the AB system, not corrected for Galactic extinction in the direction of the GRB, and calibrated relative to USNO-B1. We find that source #5 has remained approximately constant in flux over a 2 day period. It has not faded and is therefore unlikely to be the afterglow of GRB 130310A. This source is not detected in the Z, Y, J, or H bands. We also note that we have searched for additional fading sources (delta_mag > 0.5) in all bands and have found none. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.