//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9018 SUBJECT: GRB 090320A: Fermi GBM detection DATE: 09/03/23 14:53:00 GMT FROM: Arne Rau at MPE Arne Rau (MPE) reports on behalf of the Fermi GBM Team: "At 10:01:46 UT on 20 March 2009, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 090320A (trigger 259236108 / 090320.418). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 242.4, Dec = -51.9 (J2000 degrees, equivalent to J2000 16h 10m, +/-51d 54'), with a statistical uncertainty of 10.8 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The GBM light curve shows a single peak with a duration (T90) of about 10 s (8-1000 keV). The reliability for T90 is low due to strong background fluctuations. The angle from the Fermi LAT boresight is 60 degrees. Since the source is weak, the time-averaged spectrum is poorly constrained." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9020 SUBJECT: GRB 090320B: Fermi GBM detection. DATE: 09/03/23 15:39:21 GMT FROM: Narayana Bhat at U Alabama/Huntsville/GBM P. N. Bhat (UAH) report on behalf of the Fermi GBM Team: At 19:13:46.10 UT on 20 March 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090320B (trigger 259269228 / 090320801). The on-ground calculated location, using the GBM trigger data, is RA = 183.8, DEC = 57.6 (J2000 degrees, equivalent to 12 h 15.3 m, 57 d 33 '), with an uncertainty of 9.6 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 101 degrees. The GBM light curve shows one main pulse with several weaker trailing pulses with a duration (T90) of about 52 s (8-1000 keV). The time-averaged spectrum from T0-7.4 s to T0+52 s is adequately fit by a power law function with an exponential high energy cutoff. The power law index is -1.1 +/- 0.3 and the cutoff energy, parameterized as Epeak, is 72 +/- 14 keV (chi squared 255 for 237 d.o.f.). The event fluence (8-1000 keV) in this time interval is (1.1 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0 s in the 8-1000 keV band is 0.12 +/- 0.04 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: 9022 SUBJECT: GRB 090320C: Fermi GBM Detection DATE: 09/03/23 21:38:57 GMT FROM: Vandiver Chaplin at UAH/Fermi-GBM V.Chaplin (UAH) reports on behalf of the Fermi GBM Team: "At 01:05:10.53 UT on 20 March 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090320C (trigger 259203912 / 090320045). The on-ground calculated location, using the GBM trigger data, is RA = 108.2, DEC = -43.3 (J2000 degrees, equivalent to 7h 13m, -43d 18'), with an uncertainty of 15.0 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 40 degrees. The GBM light curve has a duration (T90) of about 4 s (8-1000 keV), with a peak at about T0-2 seconds. Since the source is weak, the time-averaged spectrum is poorly constrained." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9038 SUBJECT: GRB 090320B: MASTER-Net prompt optical observations DATE: 09/03/25 16:39:43 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov Sternberg Astronomical Institute, Moscow State University A. Tlatov, A.V. Parhomenko, Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinski, I.Zalognikh, T.Kopytova Ural State University, Kourovka S.Yazev, K.Ivanov Irkutsk State University There are 6 MASTER Very Wide Field cameras located at Kislovodsk and Irkutsk with common FOW = 6000 square degrees (http://observ.pereplet.ru/). One of the four MASTER Very Wide Field Cameras located at Kislovodsk (D=50 mm, 4x1000 square degrees, 11 Mpx) has observed ~80% 1-sigma Fermi error box (P. N. Bhat, GCN 9020) with 1s exposure during all night: befoure, during and after GRB Time without time gap between images. Our unfiltered images are calibrated relative to Tycho stars (V). The magnitude limit of the each emage is ~9.0 m at the edge of FOW (some ising was attend at this night). We do not detect OT inside 80% part of the error box. T-T_trigger m_lim (S/N=3) Exposure Coadd -10s... 0... 60 s 9.0 1 s no -1min...0...+1 min 10.5 10 s 10 -1min...0...+1 min 11.0 60 s 60 We conclude (in the case that GRB inside our FOW ): 1). the optical fluence during the short 58 s GRBurst is limited by ~<= 1.5 x 10E-8 erg/cm_2 excluding possible host galaxy absorbtion. The event fluence (8-1000 keV) in this time interval is (1.1 +/- 0.3)E-06 erg/cm^2 (P. N. Bhat, GCN 9020). So: 2). Optical-Fluence/Gamma-Fluence(8-1000 keV) ~ < 1/70 The same ratio for long GRB080319B is Optical-Fluence/Gamma-Fluence(8 - 1000 keV) ~ 1/140 (Naked Eye GRB, Racusin, Karpov et al., Nature, vol.455, 183, 2008). The film of our observations (from -10 s before to 60 s after GRB time) is available at http://observ.pereplet.ru/images/GRB090320B/GRB090320b_10sec_bin.gif Black circle is the 1-sigma (9.5 degrees, P. N. Bhat, GCN 9020) error box. The film of added images (60s effective exposition) our observations (from -60s before to 60 s after GRB time)is available at http://observ.pereplet.ru/images/GRB090320B/GRB090320B_60sec.gif The reduction is continued. The message may be cited. mailto: lipunov@sai.msu.ru T-T_trigger m_lim (S/N=3) Exposure Coadd -255s... 0... 255 s 11.8 5s yes -2min...0...+2 min 12.7 2x30s 12 -2min...0...+2 min 13.0 2x60s 24 The optical fluence during the 40s-GRBurst is limited by <= 1.6x10_-8 erg/cm_2 including 2.8 magnitude absorbtion (Ukwatta et al., Circ 8462). The BAT-fluence is aboute 2.3x10_-6 erg/cm_2 (15-150 keV) (Fenimore et al., GCN 8468). So: Optical Fluence/Gamma-Fluence(15-150keV) ~ < 1/140 Same ratio for GRB080319B is ~ 1/25 (Naked Eye GRB) in 15-150 keV (Racusin, Karpov et al., Nature, vol.455, 183, 2008). Scientific Master Team Report are available at http://observ.pereplet.ru/images/GRB081102/grb_film.html Note: the GRB was at the edge of the FOW in both cameras. The message may be cited. mailto: lipunov@sai.msu.ru