//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13645 SUBJECT: GRB 120815A: Swift detection of a burst DATE: 12/08/15 02:24:12 GMT FROM: Scott Barthelmy at NASA/GSFC C. Pagani (U Leicester), S. D. Barthelmy (GSFC), N. Gehrels (NASA/GSFC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. Stamatikos (OSU/NASA/GSFC) report on behalf of the Swift Team: At 02:13:58 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 120815A (trigger=531003). Swift will execute a delayed slew due to Earth-limb observing constraint. The BAT on-board calculated location is RA, Dec 273.955, -52.134, which is RA(J2000) = 18h 15m 49s Dec(J2000) = -52d 08' 02" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single pulse with a duration of about 10 sec. The peak count rate was ~1500 counts/sec (15-350 keV), at ~1 sec after the trigger. Due to an observing constraint, Swift will not slew until T0+40.6 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is C. Pagani (cp232 AT star.le.ac.uk). 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: 13646 SUBJECT: GRB 120815A: TAROT La Silla observatory optical observations DATE: 12/08/15 03:28:29 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR), Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 120815A detected by SWIFT (trigger 531003) with the TAROT robotic telescope (D=25cm) located at the European Southern Observatory, La Silla observatory, Chile. The observations started 34.7s after the GRB trigger (15.4s after the notice). The elevation of the field decreased from 65 degrees above horizon and weather conditions were good. 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 with a limiting magnitude of: t0+34.7s to t0+94.7s : R > 16.3 The second image is 30.0s exposure in tracking mode: t0+108.0s to t0+138.0s : R > 18.4 We co-added a series of exposures from t0+108s to t0+1605s. Due to the annouced slew delay announced by Pagani et al. (GCNC 13645), we analyze the BAT error box. We compared the co-added TAROT images with the NOMAD1 catalog sources. Three non catalogued sources could be an optical counterpart candidate: ID ra(J2000) dec(J2000) Rmag T1 18:15:57.33 -52:07:35.6 18.5 T2 18:15:58.58 -52:07:27.5 19.0 T3 18:15:35.22 -52:05:21.4 18.3 These sources does not appear in the R filtered DSS image. The sources does not show any significant brightness variation durong 20 min. but they are close to the limiting magnitude in the individual images. Few other fainter sources are also present in the TAROT image. More informations can be found at the following URL: http://cador.obs-hp.fr/grb120815a Magnitudes are not corrected for galactic dust extinction. N.B. Galactic coordinates are lon=342.0422 lat=-15.9869 and the galactic extinction in R band is about 0.3 magnitudes estimated from D. Schlegel et al. 1998ApJ...500..525S. This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13647 SUBJECT: GRB 120815A: Swift-XRT observations DATE: 12/08/15 03:47:18 GMT FROM: Phil Evans at U of Leicester J.A. Kennea (PSU), G. Cusumano (INAF-IASF PA), M. Perri (ASDC), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester) and D.N. Burrows (PSU) report on behalf of the Swift-XRT team: The XRT began observing the field of GRB 120815A at 02:58:45.5 UT, 2686.8 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 273.95896, -52.12978 which is equivalent to: RA(J2000) = 18h 15m 50.15s Dec(J2000) = -52d 07' 47.2" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 17 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. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (8.55 x 10^20 cm^-2, Kalberla et al. 2005), with an excess column of 1.6 (+1.61/-1.45) x 10^21 cm^-2 (90% confidence). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13648 SUBJECT: GRB 120815A: GROND afterglow candidate DATE: 12/08/15 03:57:22 GMT FROM: Vladimir Sudilovsky at MPE V. Sudilovsky (MPE Garching), D. A. Kann (TLS Tautenburg) and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 120815A (Swift trigger 531003; Pagani et al., GCN 13645) simultaneously in g'r'i'z'JHKs with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG/ESO telescope at La Silla Observatory (Chile). Observations started 150 seconds after the BAT trigger, and were obtained at airmass 1.1 and a mean seeing of 1".3. Based on exposures of 142 seconds in g'r'i'z' and 240 seconds in JHK centered 348 seconds after the trigger, we detect an uncataloged source in all bands at RA (J2000): 18:15:49.82 DEC (J2000): -52:07:52.1 with an uncertainty of 0.3". This position is close to the Swift XRT position (J. A. Kennea et al., GCN 13647). We measure a preliminary magnitude: i' ~ 17.6 The magnitudes are derived based on GROND zeropoints (g'r'i'z') and 2MASS stars (JHK). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13649 SUBJECT: GRB 120815A: VLT/X-shooter redshift DATE: 12/08/15 05:40:11 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK/NBI), S. Schulze (PUC and MCSS), A. de Ugarte Postigo (IAA/CSIC and DARK/NBI), D. Xu (WIS), V. D'Elia (INAF/Roma and ASI/ASDC), J. P. U. Fynbo (DARK/NBI), N. R. Tanvir (Univ. Leicester), report on behalf of a larger collaboration: We observed the field of GRB 120815A (Pagani et al., GCN 13645) with the VLT/X-shooter spectrograph. We confirm the presence of a bright, uncatalogued object consistent with the GROND position (Sudilovsky et al., GCN 13648). From the acquisition images, we measure R = 18.9 for the afterglow at an epoch of 1.67 hr after the GRB (calibrated to nearby USNO stars). Our spectra cover the wavelength range 3000-25000 AA, and were taken starting on 2012 Aug 15.163 UT (1.69 hr after the GRB), for a total of 40 min exposure. Continuum from the afterglow is detected with high S/N in all of the UVB, VIS, and NIR arms. The spectrum shows a wide trough and a multitude of strong absorption lines, which we interpret as due to a DLA and metal transitions of N V, S II, Si II, O I, C IV, Si IV, Fe II, Al II, Al III, Mn II, Mg II, Mg I, among others, at a common redshift z = 2.358. At the same redshift, we also detect fine-structure lines of Ni II and Fe II, thus confirming conclusively that this is the GRB redshift. We also detect intervening systems at z = 1.539, 1.693, and 2.00. In particular, the system at z = 1.539 displays exceptionally strong Mg II, Mg I, and Fe II absorption. We acknowledge the expert support of the VLT observing staff at Paranal, in particular Maja Vuckovic, Marcelo Lopez, and Thomas Rivinius. We also thank Alex Kann for discussion on the afterglow identification. [GCN OPS NOTE(15aug12): Per author's request, ML and TR were added to the last paragraph.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13650 SUBJECT: GRB 120815A: Enhanced Swift-XRT position DATE: 12/08/15 06:31:40 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 1694 s of XRT Photon Counting mode data and 6 UVOT images for GRB 120815A, 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 = 273.95807, -52.13142 which is equivalent to: RA (J2000): 18h 15m 49.94s Dec (J2000): -52d 07' 53.1" with an uncertainty of 1.6 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: 13652 SUBJECT: GRB 120815A: Swift-BAT refined analysis DATE: 12/08/15 13:14:58 GMT FROM: Scott Barthelmy at NASA/GSFC C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. Pagani (U Leicester), 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 recent telemetry downlinks, we report further analysis of BAT GRB 120815A (trigger #531003) (Pagani, et al., GCN Circ. 13645). The BAT ground-calculated position is RA, Dec = 273.976, -52.125 deg, which is RA(J2000) = 18h 15m 54.4s Dec(J2000) = -52d 07' 29.0" with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment). The partial coding was 28%. The mask-weighted light curve shows a FRED pulse starting at ~T-0.3 sec, peaking at ~T+0.5 sec, and ending at ~T+30 sec. T90 (15-350 keV) is 9.7 +- 2.5 sec (estimated error including systematics). The time-averaged spectrum from T-0.24 to T+11.97 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 2.29 +- 0.23. The fluence in the 15-150 keV band is 4.9 +- 0.7 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from T+0.17 sec in the 15-150 keV band is 2.2 +- 0.3 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/531003/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13653 SUBJECT: GRB 120815A: Swift-XRT refined Analysis DATE: 12/08/15 20:04:33 GMT FROM: Claudio Pagani at U of Leicester C. Pagani (U Leicester) reports on behalf of the Swift-XRT team: We have analysed 8.5 ks of XRT data for GRB 120815A (Pagani et al. GCN Circ. 13645), from 2.7 ks to 39.5 ks after the BAT trigger. The data are entirely in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN. Circ 13650). The light curve can be modelled with a power-law decay with a decay index of alpha=0.89 (+/-0.07). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.85 (+0.12, -0.11). The best-fitting absorption column is 5.5 (+4.2, -3.8) x 10^21 cm^-2, at a redshift of 2.358, in addition to the Galactic value of 8.6 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 4.0 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 8.6 x 10^20 cm^-2 Intrinsic column: 5.5 (+4.2, -3.8) x 10^21 cm^-2 at z=2.358 Photon index: 1.85 (+0.12, -0.11) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00531003. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13666 SUBJECT: GRB 120815A: Swift/UVOT Detection of the Optical Afterglow DATE: 12/08/17 12:25:18 GMT FROM: Stephen Holland at STScI S. T. Holland (STScI) and C. Pagani (U Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT observed the field of GRB 120815A starting 2672 s after the BAT trigger (Pagani et al., 2012, GCNC 13645). Settled observations started at 2690 s. We detect an uncatalogued source inside the UVOT-enhanced XRT error circle (Goad et al., 2012, GCNC 13650) with preliminary coordinates RA (J2000.0) 18:15:49.88 = 273.95783 (deg) Dec (J2000.0) -52:07:52.1 = -52.13114 (deg) and an estimated uncertainty of 0.6 arcsec (radius, 90% confidence, statistical + systematic). The UVOT detection is consistent with the optical afterglow reported by Sudilovsky et al. (2012, GCNC 13648) Source magnitudes and 3-sigma upper limits at this location are given below. The afterglow is 4.27 arcsec northeast of the USNO-B1.0 source 0378-0977505, so the following photometry should be considered preliminary. Filter TSTART TSTOP Exp Time Mag Err Sigma ------------------------------------------------------------ v 2847 3046 100 19.34 0.29 3.9 b 3667 4120 226 20.11 0.24 4.7 u 3462 3661 100 >20.5 uvw1 3257 3457 100 >20.2 uvm2 3052 3252 100 >19.9 uvw2 4330 4530 100 >20.3 white 2690 2840 75 19.94 0.19 5.8 ------------------------------------------------------------ The quoted magnitudes and upper limits have not been corrected for the Galactic extinction along the line of sight to this burst of E_{B-V} = 0.10 mag (Schlafly et al. 2011, ApJS, 737, 103). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 13677 SUBJECT: GRB 120815A: MASTER-ICATE observations DATE: 12/08/18 15:44:50 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs H. Levato and C. Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) C. Mallamaci, C. Lopez and F. Podest Observatorio Astronomico Felix Aguilar (OAFA) E. Gorbovskoy, V. Lipunov, V. Kornilov, D. Denisenko, A. Kuznetsov, D. Kuvshinov, A. Belinski, N. Tyurina, N. Shatskiy, P. Balanutsa, D. Zimnukhov, V.V. Chazov Lomonosov Moscow State University, Sternberg Astronomical Institute A. Tlatov, A.V. Parhomenko, D. Dormidontov, V. Sennik Kislovodsk Solar Station of the Pulkovo Observatory K. Ivanov, S. Yazev, N.M. Budnev, O. Gres, O. Chuvalaev, V.A. Poleshchuk Irkutsk State University V. Yurkov, Yu. Sergienko, D. Varda, E. Sinyakov Blagoveschensk Educational State University, Blagoveschensk V. Krushinski, I. Zalozhnich, A. Popov, A. Bourdanov, A. Punanova Ural Federal University MASTER-ICATE robotic very wide field cameras (FOV=2x384 square degrees, D=72mm, f/1.2, 1 pix = 22 arcsec, http://observ.pereplet.ru) located in Argentina (Observatorio Astronomico Felix Aguilar, http://93.180.27.230:8080/) were pointed to the GRB120815A (C. Pagani, GCN 13645) 37 s after notice time and 60 s after GRB time at 2012-08-15 02:13:58 UT. We haven`t found optical transient within SWIFT error-box our first (5 s exposure) set. The 5-sigma upper limit has been about 12.0 mag The 5-sigma upper limit on coadd first 30 images is about 13.0 mag. Our cameras are continuously imaging the sky with 5 sec exposures. This message can be cited.