//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17269 SUBJECT: GRB 150103A: Swift detection of a burst DATE: 15/01/03 20:17:37 GMT FROM: Neil Gehrels at GSFC L. M. Z. Hagen (PSU), J. R. Cummings (NASA/UMBC), N. Gehrels (NASA/GSFC), M.E. Gropp (PSU), J. A. Kennea (PSU), H. A. Krimm (CRESST/GSFC/USRA) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 20:02:18 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150103A (trigger=623368). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 131.639, -48.890 which is RA(J2000) = 08h 46m 33s Dec(J2000) = -48d 53' 24" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak about 40 seconds long. The peak count rate was ~875 counts/sec (15-350 keV), at ~5 sec after the trigger. The XRT began observing the field at 20:04:29.5 UT, 130.5 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 131.66761, -48.88595 which is equivalent to: RA(J2000) = 08h 46m 40.23s Dec(J2000) = -48d 53' 09.4" with an uncertainty of 3.8 arcseconds (radius, 90% containment). This location is 69 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 consistent with the Galactic value of 8.96 x 10^21 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 135 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 large, but uncertain extinction expected. Burst Advocate for this burst is L. M. Z. Hagen (lea.zernow.hagen AT gmail.com). 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: 17270 SUBJECT: GRB 150103A: Prompt enhanced Swift-XRT position DATE: 15/01/03 20:37:39 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Using promptly downlinked XRT event data for GRB 150103A, we find an enhanced XRT position of the afterglow: RA, Dec: 131.6663, -48.8863 which is equivalent to: RA (J2000) = 08 46 39.92 Dec (J2000) = -48 53 10.6 with an uncertainty of 2.0 arcseconds (radius, 90% confidence). Analysis of the promptly available data is online at http://www.swift.ac.uk/sper/623368. Position enhancement is 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: 17272 SUBJECT: GRB 150103A: Enhanced Swift-XRT position DATE: 15/01/03 22:59:18 GMT FROM: Phil Evans at U of Leicester J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift-XRT team. Using 1050 s of XRT Photon Counting mode data and 1 UVOT images for GRB 150103A, 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 = 131.66600, -48.88593 which is equivalent to: RA (J2000): 08h 46m 39.84s Dec (J2000): -48d 53' 09.4" with an uncertainty of 1.8 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: 17273 SUBJECT: GRB 150103A: Zadko observatory - Gingin optical observations DATE: 15/01/04 00:47:23 GMT FROM: Alain Klotz at IRAP-CNRS-OMP A. Klotz, D. Turpin (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR), D. Coward (UWA), M. Boer, B. Gendre, K. Siellez, H. Dereli, O. Bardho (UNS-CNRS-OCA), A. Williams (PO-UWA), R. Martin (PO-UWA) report: We imaged the field of GRB 150103A detected by SWIFT (trigger 623368) with the Zadko robotic telescope (D=100cm) located at the observatory - Gingin, Australia. The observations started 121.6s after the GRB trigger (44.7s after the notice). The elevation of the field decreased from 62 degrees above horizon and weather conditions were good but during the dawn. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT in the XRT error box provided by Osborne et al. (GCNC 17272) with a limiting magnitude of: t0+121.6s to t0+181.6s : Rlim = 16.7 The second image is 30.0s exposure in tracking mode: t0+200.0s to t0+230.0s : Rlim = 18.9 The following images give the same limits: t0+239s to t0+347s : Rlim = 18.9 Images taken later are saturated due to the dawn. Magnitudes were estimated with the nearby NOMAD1 stars and are not corrected for galactic dust extinction. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17274 SUBJECT: GRB 150103A: Swift-BAT refined analysis DATE: 15/01/04 01:59:55 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift J. R. Cummings, S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150103A (trigger #623368) (Hagen, et al., GCN Circ. 17269). The BAT ground-calculated position is RA, Dec = 131.674, -48.896 deg which is RA(J2000) = 08h 46m 41.9s Dec(J2000) = -48d 53' 45.2" with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 67%. The mask-weighted light curve shows a single broad peak. T90 (15-350 keV) is 49.1 +- 9.8 sec (estimated error including systematics). The time-averaged spectrum from T+6.06 to T+64.68 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index -0.03 +- 1.01, and Epeak of 54.2 +- 12.8 keV (chi squared 54.70 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 8.2 +- 1.3 x 10^-07 erg/cm2 and the 1-sec peak flux measured from T+26.32 sec in the 15-150 keV band is 0.5 +- 0.2 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.61 +- 0.18 (chi squared 66.38 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/623368/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17275 SUBJECT: GRB 150103A: Swift/UVOT Upper Limits DATE: 15/01/04 04:04:17 GMT FROM: Lea Hagen at PSU L. M. Z. Hagen (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150103A 135 s after the BAT trigger (Hagen et al., GCN Circ. 17269). No optical afterglow consistent with the XRT position (Osborne et al. GCN Circ. 17272) 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) exposures and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white (fc) 135 284 147 >20.49 white 573 7047 618 >21.08 v 624 6018 293 >19.31 b 549 6841 471 >20.41 u (fc) 293 543 245 >19.66 u 698 6635 451 >19.95 uvw1 673 6429 471 >19.73 uvm2 648 6224 471 >19.54 uvw2 599 7179 417 >19.67 The magnitudes in the table are not corrected for the Galactic extinction due to the large, but uncertain, reddening of E(B-V) = 1.46 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17277 SUBJECT: GRB 150103A: Swift-XRT refined Analysis DATE: 15/01/04 10:17:24 GMT FROM: Phil Evans at U of Leicester M.C. Stroh (PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), B.P. Gompertz (U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), M. de Pasquale (INAF-IASFPA) and L.M.Z. Hagen report on behalf of the Swift-XRT team: We have analysed 7.8 ks of XRT data for GRB 150103A (Hagen et al. GCN Circ. 17269), from 116 s to 22.0 ks after the BAT trigger. The data comprise 231 s in Windowed Timing (WT) mode (the first 7 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 Osborne et al. (GCN Circ. 17270). The light curve can be modelled with an initial power-law decay with an index of alpha=0.65 (+0.27, -1.19), followed by a break at T+416 s to an alpha of 2.56 (+0.47, -0.27). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.15 (+0.16, -0.15). The best-fitting absorption column is 1.53 (+0.30, -0.27) x 10^22 cm^-2, in excess of the Galactic value of 9.0 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.8 (+0.4, -0.3) and a best-fitting absorption column of 1.9 (+0.6, -0.5) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 6.5 x 10^-11 (1.2 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.9 (+0.6, -0.5) x 10^22 cm^-2 Galactic foreground: 9.0 x 10^21 cm^-2 Excess significance: 3.3 sigma Photon index: 1.8 (+0.4, -0.3) If the light curve continues to decay with a power-law decay index of 2.56, the count rate at T+24 hours will be 3.0 x 10^-6 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.9 x 10^-16 (3.6 x 10^-16) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00623368. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17279 SUBJECT: GRB 150103A: MASTER optical observations DATE: 15/01/04 13:53:58 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D.Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory E. Gorbovskoy,V. Lipunov, N.Tyurina, P.Balanutsa, D.Denisenko, M.Pruzhinskaya, A.Kuznetsov, V.Kornilov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute O.Gres, K.Ivanov, S.Yazev, N.M.Budnev, V.A.Poleshchuk Irkutsk State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Kourovka H. Levato and C. Saffe Instituto de Ciencias Astronomicas de la Tierra y del Espacio (ICATE), San Juan, Argentina C. Mallamacci, C. Lopez and F. Podest Observatorio Astronomico Felix Aguilar (OAFA), San Juan National University, Argentina MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in South Africa (Sutherland) was pointed to the GRB150103A 33 sec after notice time and 115 sec after trigger time at 2015-01-03 20:04:14 UT. On our first (20s exposure) set we haven`t found optical transient within SWIFT error-box (Hagen et al., GCN Circ 17269; Evans, GCN Circ 17270; Cummings et al., GCN Circ 17274; Stroh et al., GCN Circ 17277). The 5-sigma upper limit has been about 17.0mag This limit slightly yearly than Zadko (Klotz et al., GCN CIRC 17273) and Swift UVOT (Hagen, GCN CIRC 17275), but not contradict to them. This message may be cited.