//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23551 SUBJECT: GRB 181222B : Fermi GBM detection DATE: 18/12/23 05:35:51 GMT FROM: Peter Veres at UAH P Veres (UAH) reports on behalf of the Fermi GBM Team: "At 20:11:37.438 UT on 22 December 2018, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 181222B (trigger 567202302 / 181222841). The on-ground calculated location, using the GBM trigger data, is RA = 311.2, DEC = 22.9 (J2000 degrees, equivalent to 22 h 45 m, 22 d 52 '), with an uncertainty of 1.6 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which we have characterized as a core-plus-tail model, with 90% of GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ). The angle from the Fermi LAT boresight at the GBM trigger time is 65 degrees. The GBM light curve shows a very intense peak with a duration (T90) of about 0.5 s (50-300 keV). The time-averaged spectrum from T0 to T0+1.1 s is best fit by a Band function with Epeak = 380 +/- 8 keV, alpha = -0.74 +/- 0.01, and beta = -2.98 +/- 0.11 The event fluence (10-1000 keV) in this time interval is (3.44 +/- 0.03)E-5 erg/cm^2. The 64 ms peak photon flux measured starting from T0+0.14 s in the 10-1000 keV band is 800 +/- 6 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23552 SUBJECT: GRB 181222B: Global MASTER Net observations of the short bright Fermi GRB error box. DATE: 18/12/23 10:53:54 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 Lomonosov Moscow State University, SAI, Physics Department D. Buckley, South African Astronomical Observatory R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory O. Gres, N.M. Budnev, O.Ershova, Yu.Ishmuhametov Applied Physics Institute, Irkutsk State University V. Yurkov, A. Gabovich, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk R. Podesta, Carlos Lopez, F. Podesta, C.Francile Observatorio Astronomico Felix Aguilar (OAFA) H. Levato Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) MASTER-IAC robotic telescope (4 square degreess,Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to the GRB181222B 107 sec after trigger time at 2018-12-22 20:13 24 UT in two polarizations. On our first ( 20s exposure ) set we not found optical transient within FERMI error-box (ra=311.146 dec=22.8597 r=1.6) The real time cover map is available https://master.sai.msu.ru/site/master2/event.php??not=2018-12-22%2020:20:57&sat=FERMI&gcrd=(311.146d,22.8597d)&eb=1.6&trig=2018-12-22%2020:11:37&n=GRB181222.84 ==================================================================== The galactic latitude b = -13 deg., longitude l = 67 deg. The observations made on zenit distance = 62 deg.The moon (100 % bright part) is 25 deg. above the horizon. The distance between moon and object is 122 The sun altitude is -27.2 deg. The object can be observed till sunrise at 2018-12-23 07:52:51 MASTER-Amur robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Blagoveshchensk State Pedagogical University) was starting survey on the FERMI GRB181222B error-box (20 44 35 dec=+22 51 36, r=1.6) 45931 sec after notice time and 46503 sec after trigger time at 2018-12-23 09:06:40 UT. The 5-sigma upper limit on our first (60s exposure) set is about 16.5 mag The full information about this GRB181222B available here https://176.123.192.71//master2/grb.php?not=2018-12-22+20%3A21%3A08.37&sat=FERMI&gcrd=%28311.146d%2C22.86d%29&eb=1.6&trig=2018-12-22+20%3A11%3A37&n=GRB181222.84 The message may be cited. ==================================================================== The galactic latitude b = -13 deg., longitude l = 67 deg. The observations made on zenit distance = 44 deg. The moon (99 % bright part) is 8 deg. above the horizon. The distance between moon and object is 127. Observations started at twilight. The sun altitude is -14.6 deg. The object can be observed till 2018-12-23 14:13:01. The observations and reduction continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23556 SUBJECT: IPN Triangulation of extremely bright short GRB 181222B DATE: 18/12/25 10:29:28 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team, report: The short-duration, extremely bright GRB 181222B (Veres, GCN 23551) was detected by Fermi (GBM trigger 567202302) and Konus-Wind at about 72697 s UT (20:11:37). We have triangulated it to a Konus-GBM annulus centered at RA(2000)=294.324 deg (19h 37m 18s) Dec(2000)=-23.694 deg (-23d 41' 39"), whose radius is 51.089 +/- 0.097 deg (3 sigma). The annulus reduces the area of the 3 sigma Fermi-GBM final position by about a factor of 130. This annulus may be improved. A triangulation map is posted at ttp://www.ioffe.ru/LEA/GRBs/GRB181222_T72694/IPN The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23557 SUBJECT: Konus-Wind observation of GRB 181222B DATE: 18/12/25 10:36:09 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report: The short-duration, extremely bright GRB 181222B (Fermi-GBM detection: Veres, GCN Circ. 23551; IPN triangulation: Svinkin et al., GCN Circ. 23556) triggered Konus-Wind at T0=72694.563 s UT (20:11:34.563). The burst light curve shows a single pulse which starts at about T0 and has a total duration of ~2.1 s. The emission is seen up to ~15 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB181222_T72694/ As observed by Konus-Wind, the burst had a fluence of 3.70(-0.17,+0.18)x10^-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.166 s, of 2.72(-0.25,+0.26)x10^-4 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.512 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.52(-0.08,+0.08), the high energy photon index beta = -2.95(-0.30,+0.20), the peak energy Ep = 365(-26,+27) keV (chi2 = 53/56 dof). Among ~300 bursts from the Konus catalog of short GRBs (Svinkin et al., ApJS 224, 10, 2016), GRB 181222B is within top 2% in the terms of 16-ms peak energy flux and within top 2% in the terms of the total energy fluence, both in the 20 keV - 10 MeV range. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23558 SUBJECT: GRB 181222B: Global MASTER Net observations of short bright Fermi GRB DATE: 18/12/25 11:34:42 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, D.Kobtsev Lomonosov Moscow State University, SAI R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias D. Buckley, South African Astronomical Observatory A. Tlatov, V.Senik, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, Irkutsk State University V. Yurkov, A. Gabovich, Yu. Sergienko, Blagoveschensk Educational State University, Blagoveschensk R. Podesta, C.Lopez, F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) H. Levato Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) The Global MASTER network continues to inspect error box of the short bright gamma-ray burst GRB 181222B (Veres, GCN #23551; Lipunov et al., GCN #23552) MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) started inspect survey of Fermi GRB18122B IPN error-box (Svinkin et al., GCN #23556) 36801 sec after notice time and 36801 sec after trigger time at 2018-12-24 19:07:42 UT. There are 479 galaxies in IPN localization. MASTER auto-detection system found optical transient: MASTER OT J204928.79+245744.0 detection. MASTER-IAC auto-detection system discovered OT source at (RA, Dec)=20h 49m 28.79s +24d 57m 44.0s on 2018-12-24.81773 UT. The OT unfiltered magnitude is 16.9m (limit 18.6m). The OT is seen in 2 images. There is no minor planet at this place. We have reference image without OT on 2018-08-02.04970 UT with 18.7m unfiltered magnitude limit . There is red start in PanSTARR (rmag=21.7) and SDSS.9 (r=21.9) Spectral observations are required. Observations started at twilight.The sun altitude was -11.5 deg. The observations made on zenit distance = 29 deg. The moon (94 % bright part) below the horizon The altitude of the Moon is -14 deg. The object can be observed till 2018-12-25 00:54:38. The galactic latitude b = -60 deg., longitude l = 98 deg. MASTER-Amur robotic telescope located in Russia (Blagoveshchensk State Pedagogical University) was pointed to the FERMI GRB181222B 46503 sec after trigger time at 2018-12-23 09:06:40 UT, with upper limit up to 17.8 mag. Observations started at twilight. The observations began at zenit distance = 44 deg. The sun altitude is -14.2 deg. MASTER-Tunka robotic telescope located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the FERMI GRB181222B 52255 sec after trigger time at 2018-12-23 10:42:32 UT, with upper limit up to 18.6 mag. Observations started at twilight. The observations began at zenit distance = 44 deg. The sun altitude is -14.5 deg. The cover map is available at https://master.sai.msu.ru/site/master2/observ.php?id=890715 The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23568 SUBJECT: GRB 181222B: Swift ToO observations DATE: 18/12/27 16:22:51 GMT FROM: Phil Evans at U of Leicester P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the Fermi+MASTER GRB 181222B. Automated analysis of the XRT data will be presented online at http://www.swift.ac.uk/ToO_GRBs/00020850 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Fermi+MASTER event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23582 SUBJECT: GRB 181222B: Swift follow-up observations of MASTER optical transient J204928.79+245744.0 DATE: 18/12/28 17:36:50 GMT FROM: Antonino D'Ai at IASF-PA A. Tohuvavohu (PSU), A. D'Ai (INAF-IASFPA), M. Siegel (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB), and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT and Swift-UVOT teams: Swift has performed follow-up observations of the MASTER optical transient J204928.79+245744.0 (V. Lipunov et al. GCN Circ. 23588), within the IPN localization region of Fermi/GBM and Konus detected GRB 181222B (P. Veres GCN Circ. 23551, D. Svinkin et al. GCN Circ. 23556). Swift/XRT collected 3.9 ks of Photon Counting (PC) mode data between T0+414.9 ks and T0+427.0 ks. No X-ray source was detected at the MASTER position with an upper limit of 2.4 e-3 ct s^-1. Two uncatalogued X-ray sources have been detected in the field during this observation. Both sources are below the RASS limit and show no definitive signs of fading. Given the large localization region of this burst and the amount of time elapsed between the GRB and these observations, we believe it unlikely that these X-ray sources are related to the GRB. Details of the sources are given below: Source 1: RA (J2000.0): 312.2708 = 20:49:52.88 Dec (J2000.0): +25.0419= +25:02:30.9 Error: 2.5 arcsec (radius, 90% conf.) Count-rate (9.9 [+2.0, -1.9])e-3 ct s^-1 Distance: 7.2 arcminutes from MASTER position. Flux: (2.3 [+0.5, -0.4])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 2: RA (J2000.0): 312.3700 = 20:49:28.81 Dec (J2000.0): +24.9769 = +24:58:37.0 Error: 7.7 arcsec (radius, 90% conf.) Count-rate: (3.03 [+1.21, -0.97])e-3 ct s^-1 Distance: 53 arcsec from MASTER position. Flux: (1.22 [+0.49, -0.39])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV). Swift/UVOT began observing the field in the White filter 414 ks after the GRB trigger. We do not find any optical source at the MASTER position, with an upper limit of 21.48 +/- 0.22 magnitude (AB) in a 3094 second exposure. This magnitude is not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.24 in the direction of the burst (Schlegel et al. 1998). The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at http://www.swift.ac.uk/ToO_GRBs/00020850/. This circular is an official product of the Swift team.