//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25082 SUBJECT: GRB 190718A: Swift detection of a burst DATE: 19/07/18 04:51:09 GMT FROM: David Palmer at LANL V. D'Elia (SSDC), E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA), N. J. Klingler (PSU), D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 04:41:15 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 190718A (trigger=915091). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 336.531, -41.221 which is RA(J2000) = 22h 26m 07s Dec(J2000) = -41d 13' 13" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a complex structure with a duration of about 20 sec. The peak count rate was ~1700 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 04:42:21.5 UT, 66.4 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 336.57614, -41.20264 which is equivalent to: RA(J2000) = 22h 26m 18.27s Dec(J2000) = -41d 12' 09.5" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 138 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 (1.24 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.3 (+2.81/-2.43) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 69 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 none of the XRT error circle. 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 expected extinction corresponding to E(B-V) of 0.01. Burst Advocate for this burst is V. D'Elia (delia AT ssdc.asi.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/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25083 SUBJECT: Swift GRB190718.2 Global MASTER-Net observations report DATE: 19/07/18 05:28:22 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias) D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB190718.2 (trigger No 915091, 22h 26m 07.44s , -41d 13m 15.60s, R=0.05) errorbox 18 sec after notice time and 44 sec after trigger time at 2019-07-18 04:41:59 UT, with upper limit up to 17.0 mag. Observations started at twilight. The observations began at zenit distance = 40 deg. The sun altitude is -11.6 deg. MASTER-OAFA robotic telescope located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB190718.2 errorbox 32 sec after notice time and 57 sec after trigger time at 2019-07-18 04:42:12 UT, with upper limit up to 17.1 mag. The observations began at zenit distance = 33 deg. The sun altitude is -80.1 deg. MASTER-IAC robotic telescope located in Spain (IAC Teide Observatory) was pointed to the Swift GRB190718.2 errorbox 55 sec after notice time and 80 sec after trigger time at 2019-07-18 04:42:35 UT, with upper limit up to 16.8 mag. The observations began at zenit distance = 71 deg. The sun altitude is -18.8 deg. The galactic latitude b = -60 deg., longitude l = 98 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1077929 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 49 | MASTER-SAAO | P\ | 10 | 15.7 | 64 | MASTER-SAAO | P\ | 40 | 16.5 | Coadd 63 | MASTER-OAFA | C | 10 | 15.4 | 88 | MASTER-OAFA | C | 60 | 16.4 | Coadd 75 | MASTER-SAAO | P\ | 10 | 15.7 | 86 | MASTER-IAC | P| | 10 | 16.2 | 105 | MASTER-SAAO | P\ | 20 | 16.1 | 120 | MASTER-OAFA | C | 20 | 15.7 | 139 | MASTER-IAC | P| | 20 | 16.8 | 147 | MASTER-SAAO | P\ | 30 | 16.3 | 192 | MASTER-SAAO | P\ | 120 | 16.9 | Coadd 186 | MASTER-OAFA | C | 30 | 15.8 | 196 | MASTER-SAAO | P\ | 40 | 16.3 | 268 | MASTER-SAAO | P\ | 50 | 16.3 | 271 | MASTER-OAFA | C | 50 | 16.1 | 339 | MASTER-SAAO | P\ | 60 | 16.3 | 429 | MASTER-SAAO | P\ | 240 | 17.0 | Coadd 374 | MASTER-OAFA | C | 70 | 16.2 | 430 | MASTER-SAAO | P\ | 80 | 16.3 | 497 | MASTER-OAFA | C | 90 | 16.3 | 536 | MASTER-SAAO | P\ | 100 | 16.3 | 643 | MASTER-OAFA | C | 120 | 16.5 | 808 | MASTER-OAFA | C | 450 | 17.1 | Coadd 664 | MASTER-SAAO | P\ | 120 | 16.2 | 815 | MASTER-SAAO | P\ | 150 | 15.9 | 821 | MASTER-OAFA | C | 150 | 16.5 | 1027 | MASTER-OAFA | C | 180 | 16.6 | 1247 | MASTER-OAFA | C | 180 | 16.5 | 1468 | MASTER-OAFA | C | 180 | 16.5 | 1691 | MASTER-OAFA | C | 180 | 16.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25084 SUBJECT: GRB 190718A: Enhanced Swift-XRT position DATE: 19/07/18 11:41:22 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 1160 s of XRT Photon Counting mode data and 2 UVOT images for GRB 190718A, 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 = 336.57610, -41.20446 which is equivalent to: RA (J2000): 22h 26m 18.26s Dec (J2000): -41d 12' 16.1" with an uncertainty of 1.7 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: 25085 SUBJECT: GRB 190718A: FRAM-Auger optical limit DATE: 19/07/18 12:52:21 GMT FROM: Martin Jelinek at Astro.Inst-AVCR,Ondrejov Martin Jelinek, Jan Strobl (ASU CAS Ondrejov, CZ), Martin Masek, Petr Janecek, Sergey Karpov, Jakub Jurysek, Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza (Institute of Physics, Prague, CZ) report: The 30cm robotic telescope FRAM-Auger in Malargue (Argentina) reacted robotically to the Swift/BAT alert of GRB190718A (D'Elia et al., GCNC 25082), starting with a series of 20s unfiltered images at 04:45:11 UT, i.e. 236s post trigger. We do not detect any new source at or around the reported X-ray errorbox reported by Evans et al. (GCN 25084) at single frames or a combined 20 x 20s image taken between 236s and 1123s after the initial trigger. The combined exposure has a limiting magnitude r'(AB) = 18.0, as calibrated against the APASS Catalogue. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25089 SUBJECT: GRB 190718A: Swift/UVOT Upper Limits DATE: 19/07/18 16:18:19 GMT FROM: Samantha Oates at MSSL S. R. Oates (U.Warwick) and V. D'Elia (SSDC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 190718A 70 s after the BAT trigger (D'Elia et al., GCN Circ. 25082). No optical afterglow consistent with the XRT position (Evans et al., GCN Circ. 25084) 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 70 219 147 >20.9 u_FC 282 532 246 >20.0 white 70 1184 353 >21.0 v 612 1061 78 >18.3 b 538 1159 58 >19.1 u 282 4874 307 >20.0 w1 661 4847 235 >19.6 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25093 SUBJECT: GRB 190718A: Swift-XRT refined Analysis DATE: 19/07/18 18:29:45 GMT FROM: Phil Evans at U of Leicester B. Sbarufatti (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , D.N. Burrows (PSU), J. D. Gropp (PSU) and V. D'Elia report on behalf of the Swift-XRT team: We have analysed 6.4 ks of XRT data for GRB 190718A (D'Elia et al. GCN Circ. 25082), from 70 s to 41.2 ks after the BAT trigger. The data comprise 349 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 25084). The late-time light curve (from T0+4.6 ks) can be modelled with a power-law decay with a decay index of alpha=1.03 (+0.18, -0.17). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.64 (+0.15, -0.14). The best-fitting absorption column is 7.0 (+4.2, -3.8) x 10^20 cm^-2, in excess of the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.0 x 10^-11 (4.4 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 7.0 (+4.2, -3.8) x 10^20 cm^-2 Galactic foreground: 1.2 x 10^20 cm^-2 Excess significance: 2.5 sigma Photon index: 1.64 (+0.15, -0.14) If the light curve continues to decay with a power-law decay index of 1.03, the count rate at T+24 hours will be 0.011 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.5 x 10^-13 (5.0 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00915091. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25097 SUBJECT: GRB 190718A: Swift-BAT refined analysis DATE: 19/07/19 01:24:16 GMT FROM: Amy Lien at GSFC D. M. Palmer (LANL), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), V. D'Elia (SSDC), H. A. Krimm (NSF), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), T. Sakamoto (AGU), M. Stamatikos (OSU), 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 190718A (trigger #915091) (D'Elia et al., GCN Circ. 25082). The BAT ground-calculated position is RA, Dec = 336.605, -41.184 deg which is RA(J2000) = 22h 26m 25.2s Dec(J2000) = -41d 11' 02.7" with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment). The partial coding was 100%. The mask-weighted light curve shows a main multi-peaked structure that starts at ~ T0 and ends at ~T+17 s. In addition, there is a weak pulse at ~T+700 s, which is at the same time as the large flare seen by the XRT. T90 (15-350 keV) is 720.0 +- 35.8 sec (estimated error including systematics). The time-averaged spectrum from T+0.1 to T+17.1 sec (i.e., the duration of the main emission) is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.38 +- 0.26. The fluence in the 15-150 keV band is 3.6 +- 0.6 x 10^-7 erg/cm2. The spectral analysis for the total burst duration from ~T0 to ~T+720 s does not produce reasonable fits due to the large quiescent period from ~T+17 s to ~T+700 s. The 1-sec peak photon flux measured from T+0.08 sec in the 15-150 keV band is 1.0 +- 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/915091/BA/