//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23915 SUBJECT: GRB 190220B: a long GRB detected by IBAS DATE: 19/02/20 22:01:11 GMT FROM: Diego Gotz at CEA D.Gotz (CEA, Saclay), S.Mereghetti (INAF, IASF-Milano), C.Ferrigno, E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC, Versoix) and J.Borkowski (CAMK, Torun) report: a gamma ray burst lasting about 200 s with a multi-peaked structure has been detected by IBAS in the IBIS/ISGRI data at 20:12:43 UT of February 20, 2019. The refined coordinates (J2000) are: R.A.= 242.4512 deg DEC.= -21.1314 deg with an uncertainty of 2.0 arcmin (90% c.l.). The burst had a peak flux of 0.2 counts/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 3.6e-6 erg/cmsq. A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23916 SUBJECT: GRB 190220B: BOOTES-4 optical observation DATE: 19/02/20 23:05:52 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia Y.-D. Hu, X.-Y.Li, E. Fernandez-Garcia, A. Ayala, A. J. Castro-Tirado (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga),  S. Guziy (Univ. of Nikolaev) and D. Xiong, Y. Fan, X. Zhao, J. Bai, C. Wang, Y. Xin (Yunnan Nacional Astronomical Observatory) on behalf of a larger collaboration, report: "Following the detection of GRB 190220B by INTEGRAL (Gotz et al. GCNC 23915), the 0.6m BOOTES-4/MET robotic telescope at Lijiang Astronomical Observatory (China) responded to the the burst gathering images starting at 20:17:12 UT (89 s after trigger, 84 s after notice). No optical afterglow candidate is found down to 18 mag (g'-band) in the co-added (5x10s) image within the reported INTEGRAL 2 arcmin radius error box. Observations are ongoing." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23919 SUBJECT: GRB 190220B: Kitab Observatory optical upper limit DATE: 19/02/21 14:58:34 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Novichonok (KIAM), A. Pozanenko (IKI), E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov (KIAM) report on behalf of larger GRB follow-up collaboration: We observed the field of INTEGRAL GRB 190220B (Gotz et al., GCN 23915) with RC-36 0.36-m telescope of Kitab Observatory starting on Feb. 20 (UT) 23:20:25 in Clear filter. We do not find any optical afterglow candidate in the INTEGRAL GRB 190220B localization error circle (Gotz, et al., GCN 23915) with is in agreement with earlier non detection by BOOTES-4 (Hu et al., GCN 23916). Preliminary photometry of the field is following. Date UT start t-T0 Filter Exp. OT Err. UL(3sigma) (mid, days) (s) 2019-02-20 23:20:25 0.14972 CR 48*60 19.0 n/d n/d The photometry is based on the nearby USNO-B1 (R2) stars. . //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23921 SUBJECT: GRB 190220B: Fermi GBM observation DATE: 19/02/21 19:49:45 GMT FROM: Cori Fletcher at USRA/NASA C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 20:15:31.49 UT on 20 February 2019, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 190220B (trigger 572386536 / 190220844). which was also detected by INTEGRAL (Gotz et al. 2019, GCN 23915). The GBM on-ground location is consistent with the INTEGRAL position. The angle from the Fermi LAT boresight at the GBM trigger time is 23 degrees. The GBM light curve consists of multiple peaks with a duration (T90) of about 109 s (50-300 keV). The time-averaged spectrum from T0-51.201 s to T0+59.393 s is well fit by a power law function with an exponential high-energy cutoff. The power law index is -1.4 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 83 +/- 8 keV The event fluence (10-1000 keV) in this time interval is (7.2 +/- 0.6)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+38.72 s in the 10-1000 keV band is 2.5 +/- 0.2 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 73 +/- 13 keV, alpha = -1.3 +/- 0.2 and beta = -2.5 +/- 0.4. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog."