//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11790 SUBJECT: GRB 110315A: Swift detection of a burst DATE: 11/03/16 00:09:22 GMT FROM: Scott Barthelmy at NASA/GSFC A. Melandri (INAF-OAB), S. D. Barthelmy (GSFC), P. D'Avanzo (INAF-OAB), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), C. Gronwall (PSU), S. T. Holland (CRESST/USRA/GSFC), E. A. Hoversten (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), V. Mangano (INAF-IASFPA), R. Margutti (INAF-OAB), C. B. Markwardt (NASA/GSFC), F. E. Marshall (NASA/GSFC), C. J. Saxton (UCL-MSSL), B. Sbarufatti (INAF-OAB/IASFPA) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 23:57:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110315A (trigger=449399). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 279.191, +17.532 which is RA(J2000) = 18h 36m 46s Dec(J2000) = +17d 31' 56" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows 3 or 4 peaks with a total duration of about 20 sec. The peak count rate was ~1200 counts/sec (15-350 keV), at ~2 sec after the trigger. The XRT began observing the field at 23:58:49.1 UT, 104.6 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 279.1928, +17.5388 which is equivalent to: RA(J2000) = 18h 36m 46.27s Dec(J2000) = +17d 32' 19.6" with an uncertainty of 5.8 arcseconds (radius, 90% containment). This location is 25 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 150 seconds with the White filter starting 112 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 coverage of the XRT error circle by the 8'x8' region for the list of sources generated on-board is uncertain because the large number of sources filled the available telemetry. No correction has been made for the expected extinction corresponding to E(B-V) of 0.25. Burst Advocate for this burst is A. Melandri (andrea.melandri AT brera.inaf.it). 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: 11791 SUBJECT: GRB 110315A: MASTER early optical observations DATE: 11/03/16 09:37:25 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov, D.Zimnukhov, M. Kornilov, A.V.Krylov, V.Shumkov, S.Shurpakov Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, I.Kudelina Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnich, A. Popov Ural State University, Kourovka K.Ivanov, O.Chuvalaev, V.Poleschuk, E.Konstantinov, V.Lenok, O.Gres, S.Yazev, N.M.Budnev, Irkutsk State University MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in Kislovodsk was pointed to the GRB110315A (Melandri et al., GCN 11790) 44 sec s after notice time and 89 sec after GRB time at 2011-03-15 23:58:33.212 UT. On our first (20s exposure) set we haven`t found optical transient within SWIFT BAT error-box (ra=18 36 45 dec=+17 31 48 ). The 3-sigma upper limit has been about 17.3 mag The upper limit for 25 coadded images is 20.0 started 23:58:33.212 UT (mean time after trigger is 3240 sec ). The Galactic absroption in this direction is about 1 mag (Kalbela et al., 2005, A&A,440,775). The message may be cited. mailto: lipunov@sai.msu.ru //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11792 SUBJECT: GRB 110315A: Enhanced Swift-XRT position DATE: 11/03/16 12:21:48 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 8887 s of XRT Photon Counting mode data and 15 UVOT images for GRB 110315A, 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 = 279.19531, +17.53899 which is equivalent to: RA (J2000): 18h 36m 46.87s Dec (J2000): +17d 32' 20.4" with an uncertainty of 1.4 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: 11793 SUBJECT: GRB 110315A: Swift-BAT refined analysis DATE: 11/03/16 13:47:11 GMT FROM: Scott Barthelmy at NASA/GSFC H. A. Krimm (GSFC/USRA), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), C. B. Markwardt (GSFC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (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 110315A (trigger #449399) (Melandri, et al., GCN Circ. 11790). The BAT ground-calculated position is RA, Dec = 279.205, 17.537 deg which is RA(J2000) = 18h 36m 49.2s Dec(J2000) = +17d 32' 13.9" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 57%. The mask-weighted light curve shows a multi-peak structure starting at ~T-70 sec, with several peaks of approximate equal brightness at T-21, T-3, T+3, and T+17 sec, and then returning to background at ~T+90 sec. There is weak emission (~2 sigma) in the BAT 15-25 keV band starting at ~T+440 out to ~T+580 sec. This is likley associated with the flare in the XRT lightcurve at ~T+500 sec. T90 (15-350 keV) is 77 +- 12 sec (estimated error including systematics). The time-averaged spectrum from T-66.8 to T+38.8 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.77 +- 0.08. The fluence in the 15-150 keV band is 4.1 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+3.13 sec in the 15-150 keV band is 1.7 +- 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/449399/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11794 SUBJECT: GRB 110315A: Swift-XRT refined Analysis DATE: 11/03/16 15:26:41 GMT FROM: Andrea Melandri at INAF-OAB A. Melandri, B. Sbarufatti, R. Margutti and P. D'Avanzo (INAF-OAB) report on behalf of the Swift-XRT team: We have analysed 14 ks of XRT data for GRB 110315A (Melandri et al. GCN Circ. 11790), from 94 s to 34.8 ks after the BAT trigger. The data comprise 97 s in Windowed Timing (WT) mode (the first 8 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 11792). The light curve can be modelled with an initial power-law decay with an index of alpha=2.48 (+0.64, -0.53), followed by a break at T+150 s to an alpha of 1.03 (+0.03, -0.03). Flaring activity is detected around T+500 s. A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.14 (+0.26, -0.24). The best-fitting absorption column is 2.5 (+0.8, -0.7) x 10^21 cm^-2, in excess of the Galactic value of 1.8 x 10^21 cm^-2 (Kalberla et al. 2005). The PC mode spectrum has a photon index of 2.19 (+0.15, -0.12) and a best-fitting absorption column of 2.7 (+/-0.4) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.9 x 10^-11 (6.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.7 (+/-0.4) x 10^21 cm^-2 Galactic foreground: 1.8 x 10^21 cm^-2 Excess significance: 10.0 sigma Photon index: 2.19 (+0.15, -0.12) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00449399. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11795 SUBJECT: GRB 110315A: Swift/UVOT Upper Limits DATE: 11/03/16 15:54:41 GMT FROM: Erik Hoversten at Swift/Penn State E. A. Hoversten (PSU) and A. Melandri (INAF-OAB) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 110315A 113 s after the BAT trigger (Melandri et al., GCN Circ. 11790). No optical afterglow consistent with the enhanced XRT position (Beardmore et al., GCN Circ. 11792) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 113 263 147 >20.5 u_FC 325 559 230 >19.7 white 113 12119 1275 >21.8 The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.25 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11796 SUBJECT: GRB 110315A: RTT150 optical observations DATE: 11/03/16 21:19:32 GMT FROM: Rodion Burenin at IKI, Moscow I. Bikmaev, R. Zhuchkov, N. Sakhibullin (Kazan University), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), Z. Eker, I. Khamitov (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.) report: The field of GRB 110315A (Melandri et al., GCN 11790) was observed with Russian-Turkish 1.5-m telescope (RTT150, Bakirlitepe, TUBITAK National Observatory, Turkey) in March 16, 2011, during UT 01:05 - 03:15, i.e. starting approximately 1 hour after the burst. A serie of 21 exposures by 300 sec each in Rc filter was obtained. We found no optical source within the 1.4'' enhanced XRT error circle (Beardmore et al., GCN 11792) in our combined image at a limiting magnitude of Rc =~ 23.6 mag.