//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18389 SUBJECT: Swift Trigger 657564: a probable GRB DATE: 15/10/04 18:19:25 GMT FROM: Scott Barthelmy at NASA/GSFC S. B. Cenko (GSFC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (INAF-OAB/PSU), E. Troja (NASA/GSFC/UMCP) and T. N. Ukwatta (LANL) report on behalf of the Swift Team: At 18:09:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 151004A (trigger=657564). Swift did not slew due to the Earth-limb observing constraint. The BAT on-board calculated location is RA, Dec 213.585, -64.947, which is RA(J2000) = 14h 14m 20s Dec(J2000) = -64d 56' 49" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for image triggers, the real-time light curve does not show anything significant. Due to an observing constraint, Swift will not slew until T0+56.9 minutes. There will be no XRT or UVOT data until this time. Burst Advocate for this burst is S. B. Cenko (brad.cenko 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: 18391 SUBJECT: Swift Trigger 657564: XRT prompt analysis DATE: 15/10/04 20:15:04 GMT FROM: Claudio Pagani at U of Leicester C. Pagani (U. Leicester), P. A. Evans (U. Leicester) and S. B. Cenko (GSFC) report on behalf of the Swift-XRT Team: The XRT began observing the field of the possible GRB 151004A (Swift trigger 657564, Cenko et al., GCN Circ. 18389) at 19:09:14.0 UT, 3609.3 seconds after the BAT trigger. No source was detected in 1.1 ks of promptly downlinked data, which covered 84% of the BAT error circle. We are waiting for the full dataset to detect and localise any possible XRT counterpart. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18392 SUBJECT: Swift Trigger 657564: MASTER-NET early optical observations. DATE: 15/10/05 09:23:49 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, P.Balanutsa, A.Kuznetsov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory K.Ivanov, S.Yazev, N.M.Budnev, O.Gres, O.Chuvalaev, V.A.Poleshchuk Irkutsk State University A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk V.Krushinski, I.Zalozhnih, A. Popov Ural Federal University, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the probable GRB (Swift Trigger 657564) 24 sec after notice time and 108 sec after trigger time at 2015-10-04 18:10:55 UT. On our first (20s exposure) set we not found optical transient within SWIFT error-box (Cenko et. al GCN 18389) brighter then 16.0. Analysis of highly complicated proximity to the Milky Way (Galactic latitude l=-3.5) and strong winds (speed=65 km/h) The 5-sigma upper limit has been about 16.0 mag The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18393 SUBJECT: Trigger 657564 / GRB 151004A: Swift/UVOT Upper Limits DATE: 15/10/05 12:13:24 GMT FROM: Massimiliano de Pasquale at IASF-Palermo M. De Pasquale (UCL-MSSL) and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of the trigger 657564 (possible GRB 151004A) 3613 s after the BAT trigger (Cenko et al., GCN Circ. 18389). No optical afterglow consistent with the BAT position 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) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 3613 3763 147 >20 white 3613 4994 344 >20.3 v 3770 5404 393 >18.7 b 4590 4789 197 >19.2 u 4384 4584 197 >18.9 w1 4179 4379 197 >19.0 m2 3974 5565 350 >19.3 w2 5000 5200 197 >19.1 The magnitudes in the table are not corrected for the heavy Galactic extinction due to the reddening of E(B-V) = 1.03 in the direction of the burst (Schlegel et al. 1998). -- Dr. Massimiliano De Pasquale Research associate - Swift UVOT scientist Mullard Space Science Laboratory, University College London //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18396 SUBJECT: Trigger 657564 / GRB 151004A: Swift BAT and XRT refined analysis DATE: 15/10/05 16:20:49 GMT FROM: Amy Lien at GSFC S. D. Barthelmy (GSFC), S. B. Cenko (GSFC), J. R. Cummings (GSFC/UMBC), P.A. Evans (U. Leicester), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), D. Malesani (DARK/NBI), C. B. Markwardt (GSFC), C. Pagani (U. Leicester), K. L. Page (U. Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), and T. N. Ukwatta (LANL) report on behalf of the Swift team: Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT trigger 657564 (the probable GRB 151004A; Cenko et al., GCN Circ. 18389). The BAT ground-calculated position is RA, Dec = 213.613, -64.956 deg which is RA(J2000) = 14h 14m 27.1s Dec(J2000) = -64d 57' 23.3" with an uncertainty of 2.3 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The BAT mask-weighted light curve shows a weak complex structure that starts at ~T-10 s and ends at ~T+130 s. T90 (15-350 keV) is 128.40 +- 17.77 sec (estimated error including systematics). The BAT time-averaged spectrum from T-13.63 to T+134.42 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.95 +- 0.23. The fluence in the 15-150 keV band is 1.0 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+50.86 sec in the 15-150 keV band is 0.4 +- 0.1 ph/cm2/sec. All the quoted errors are at the 90% confidence level. In the BAT energy band, the spectral properties and T90 are consistent with those of a GRB. However, due to the low Galactic latitude (b = -3.47 deg), we cannot rule out a Galactic origin. The XRT began observing at 19:09:14.0 UT, 3610 seconds after the BAT trigger. In 5.7 ks of Photon Counting (PC) data one faint X-ray source is detected inside the BAT error circle. The astrometrically corrected X-ray position of the source (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) is: RA, Dec = 213.63218, -64.93914 which is equivalent to: RA (J2000): 14h 14m 31.72s Dec (J2000): -64d 56' 20.9" with an uncertainty of 7.0 arcsec (radius, 90% confidence). Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). The X-ray source is faint, at an average count rate of ~0.005 cnts/sec, below the RASS 3-sigma limit at this position in the sky. If the source is indeed the X-ray afterglow of GRB 151004A, it would be one of the faintest ever observed by the XRT at that time after the GRB trigger. At this time, there is only marginal evidence (1.5 sigma) of fading in the X-ray lightcurve and additional observations are required to establish the nature of the source. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/657564/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 18423 SUBJECT: GRB 151004A: Swift-XRT follow-up observations DATE: 15/10/16 13:25:03 GMT FROM: Claudio Pagani at U of Leicester C. Pagani, K. L. Page, P. A. Evans (U. Leicester) and S. B. Cenko (GSFC) report on behalf of the Swift-XRT team: A second epoch of XRT data was collected on the field of the Swift Trigger 657564 / GRB 151004A (Cenko et al., GCN Circ. 18389) on 2015 October 15. The observations consist of 7.7 ks of PC mode data, from T0+885 ks to T0+932 ks. The candidate X-ray source reported in Barthelmy et al., GCN Circ. 18396, originally detected at a count rate of 4.8 (+/- 1.14) x 10^-3 cnts/sec (0.3-10 keV) is not detected in this second epoch of observations, with a 3 sigma upper limit of 1.5 x 10^-3 cnts/sec (0.3-10 keV). The fading confirms that this is the X-ray afterglow of the Swift Trigger 657564 / GRB 151004A. This circular is an official product of the Swift-XRT team.