//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26586 SUBJECT: Swift trigger 946234/GRB 191226.02 : MASTER obervation DATE: 19/12/26 00:53:13 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, A.Chasovnikov, K.Zhirkov, A.Pozdnyakov, F.Balakin, T.Pogrosheva,D.Kuvshinov(Lomonosov MoscowState University, SAI, Physics Department), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley(South African Astronomical Observatory), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico FelixAguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), 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, D.Kobtsev (Blagoveschensk Educational State University) MASTER-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the GRB191226.02 15 sec after notice time and 105 sec after trigger time at 2019-12-26 00:32:51 UT. On our first (20s exposure) set we haven`t found optical transient within Swift error-box (ra=17.1375 dec=-57.0847 r=0.05). The 5-sigma upper limit has been about 16.0mag Error-box Altitude: 62.54 Sun: Altitude: -9.52 Observation and reduction will be continued The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26587 SUBJECT: Swift Trigger 946234 is probably not a GRB DATE: 19/12/26 01:09:25 GMT FROM: Amy Lien at GSFC M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB) and K. K. Simpson (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 00:31:05 UT, the Swift Burst Alert Telescope (BAT) triggered during the count rate increase during the approach to the SAA, and found a low-significance peak in the resulting image (trigger=946234). Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 17.141, -57.085 which is RA(J2000) = 01h 08m 34s Dec(J2000) = -57d 05' 04" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows the increasing count rate near the SAA, but does not show any significant burst structure. The XRT began observing the field at 00:33:13.7 UT, 128.4 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. This event was triggered by the BAT rate increase due to the approach to the SAA, with no peak visible at the time of the trigger, and the resulting BAT image peak has only marginal significance (6.55 sigma). In the absence of a confirmation by XRT (which had only limited exposure before it stopped taking data due to the SAA) we believe that this is probably a statistical fluctuation in the BAT image, and probably not a GRB. However, further observation and analysis of the full dataset, will be required to definitively determine the reality of this event. Burst Advocate for this burst is M. G. Bernardini (grazia.bernardini 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/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26588 SUBJECT: Swift GRB191226.02: Global MASTER-Net observations report DATE: 19/12/26 01:18:32 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, D. Cheryasov (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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB191226.02 (trigger No 946234,01h 08m 33.89s , -57d 05m 05.3s, R=0.05) errorbox 7 sec after notice time and 105 sec after trigger time at 2019-12-26 00:32:51 UT, with upper limit up to 19.9 mag. Observations started at twilight. The observations began at zenith distance = 28 deg. The sun altitude is -10.5 deg. The galactic latitude b = -60 deg., longitude l = 298 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1240059 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 116 | MASTER-OAFA | C | 20 | 16.5 | 151 | MASTER-OAFA | C | 90 | 17.4 | Coadd 381 | MASTER-OAFA | C | 550 | 18.9 | Coadd 172 | MASTER-OAFA | C | 30 | 16.8 | 238 | MASTER-OAFA | C | 40 | 17.0 | 315 | MASTER-OAFA | C | 50 | 17.2 | 395 | MASTER-OAFA | C | 210 | 18.2 | Coadd 406 | MASTER-OAFA | C | 70 | 17.6 | 517 | MASTER-OAFA | C | 90 | 18.0 | 648 | MASTER-OAFA | C | 110 | 18.2 | 808 | MASTER-OAFA | C | 430 | 19.3 | Coadd 805 | MASTER-OAFA | C | 140 | 18.5 | 997 | MASTER-OAFA | C | 180 | 18.9 | 1209 | MASTER-OAFA | C | 180 | 19.0 | 1389 | MASTER-OAFA | C | 540 | 19.9 | Coadd 1420 | MASTER-OAFA | C | 180 | 19.3 | 1631 | MASTER-OAFA | C | 180 | 19.5 | 1843 | MASTER-OAFA | C | 180 | 19.5 | 2054 | MASTER-OAFA | C | 180 | 19.6 | 2265 | MASTER-OAFA | C | 180 | 19.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26590 SUBJECT: Swift GRB191226.25: Global MASTER-Net observations report DATE: 19/12/26 06:54:11 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, D. Cheryasov (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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB191226.25 (trigger No 946256,09h 03m 26.76s , -40d 17m 50.3s, R=0.05) errorbox 18 sec after notice time and 100 sec after trigger time at 2019-12-26 05:54:44 UT, with upper limit up to 19.3 mag. The observations began at zenith distance = 19 deg. The sun altitude is -32.4 deg. The galactic latitude b = 4 deg., longitude l = 263 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1240203 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 111 | MASTER-OAFA | C | 20 | 18.1 | 167 | MASTER-OAFA | C | 30 | 18.4 | 235 | MASTER-OAFA | C | 40 | 18.5 | 311 | MASTER-OAFA | C | 50 | 18.7 | 403 | MASTER-OAFA | C | 70 | 18.8 | 514 | MASTER-OAFA | C | 90 | 19.0 | 645 | MASTER-OAFA | C | 110 | 19.1 | 802 | MASTER-OAFA | C | 140 | 19.2 | 993 | MASTER-OAFA | C | 180 | 19.3 | 1204 | MASTER-OAFA | C | 180 | 19.3 | 1416 | MASTER-OAFA | C | 180 | 19.3 | 1627 | MASTER-OAFA | C | 180 | 19.3 | 1838 | MASTER-OAFA | C | 180 | 19.3 | 2049 | MASTER-OAFA | C | 180 | 19.2 | 2260 | MASTER-OAFA | C | 180 | 19.3 | 2471 | MASTER-OAFA | C | 180 | 19.3 | 2682 | MASTER-OAFA | C | 180 | 19.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.