//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29792 SUBJECT: GRB 210411B: Fermi GBM Final Real-time Localization DATE: 21/04/11 13:43:07 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 13:32:44 UT on 11 Apr 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210411B (trigger 639840769.632692 / 210411564). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 115.7, Dec = -74.8 (J2000 degrees, equivalent to J2000 07h 42m, -74d 47'), with a statistical uncertainty of 4.5 degrees. The angle from the Fermi LAT boresight is 60.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210411564/quicklook/glg_skymap_all_bn210411564.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210411564/quicklook/glg_healpix_all_bn210411564.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210411564/quicklook/glg_lc_medres34_bn210411564.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29801 SUBJECT: Fermi GRB 210411B: Global MASTER-Net observations report DATE: 21/04/11 21:45:12 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), 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) started inspect of the Fermi GRB 210411B ( Fermi GBM team, GCN 29792) errorbox 23474 sec after notice time and 23504 sec after trigger time at 2021-04-11 20:04:29 UT, with upper limit up to 19.5 mag. The observations began at zenith distance = 48 deg. The sun altitude is -47.0 deg. The galactic latitude b = -23 deg., longitude l = 287 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1589472 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 23535 | 2021-04-11 20:04:29 | MASTER-SAAO | (08h 39m 30.90s , -77d 56m 23.8s) | C | 60 | 19.1 | 23614 | 2021-04-11 20:05:48 | MASTER-SAAO | (09h 17m 38.95s , -77d 58m 02.2s) | C | 60 | 19.1 | 23694 | 2021-04-11 20:07:08 | MASTER-SAAO | (06h 05m 46.43s , -77d 55m 48.7s) | C | 60 | 19.2 | 23774 | 2021-04-11 20:08:28 | MASTER-SAAO | (06h 44m 09.25s , -77d 56m 38.9s) | C | 60 | 19.5 | 23853 | 2021-04-11 20:09:48 | MASTER-SAAO | (06h 49m 34.90s , -69d 55m 53.0s) | C | 60 | 19.3 | 23933 | 2021-04-11 20:11:07 | MASTER-SAAO | (07h 13m 02.86s , -69d 56m 51.4s) | C | 60 | 19.1 | 24013 | 2021-04-11 20:12:27 | MASTER-SAAO | (08h 22m 55.69s , -69d 57m 59.8s) | C | 60 | 19.3 | 24331 | 2021-04-11 20:17:45 | MASTER-SAAO | (08h 49m 46.39s , -79d 56m 17.7s) | C | 60 | 19.3 | 25214 | 2021-04-11 20:32:28 | MASTER-SAAO | (06h 31m 44.71s , -79d 54m 54.6s) | C | 60 | 19.5 | 25772 | 2021-04-11 20:41:47 | MASTER-SAAO | (09h 17m 41.73s , -77d 57m 08.2s) | C | 60 | 18.5 | 25852 | 2021-04-11 20:43:06 | MASTER-SAAO | (06h 44m 10.04s , -77d 54m 52.8s) | C | 60 | 18.7 | 25932 | 2021-04-11 20:44:26 | MASTER-SAAO | (07h 12m 53.13s , -69d 55m 51.2s) | C | 60 | 17.8 | 26331 | 2021-04-11 20:51:05 | MASTER-SAAO | (06h 31m 40.60s , -79d 54m 22.4s) | C | 60 | 16.8 | 28128 | 2021-04-11 21:20:02 | MASTER-SAAO | (06h 40m 14.19s , -74d 54m 56.2s) | C | 180 | 18.5 | 28328 | 2021-04-11 21:23:22 | MASTER-SAAO | (06h 40m 12.18s , -74d 53m 09.6s) | C | 180 | 17.6 | 28528 | 2021-04-11 21:26:42 | MASTER-SAAO | (07h 20m 04.43s , -74d 54m 54.3s) | C | 180 | 17.7 | 28727 | 2021-04-11 21:30:01 | MASTER-SAAO | (07h 20m 07.24s , -74d 52m 59.5s) | C | 180 | 18.2 | 28927 | 2021-04-11 21:33:21 | MASTER-SAAO | (08h 07m 54.55s , -74d 54m 18.5s) | C | 180 | 17.7 | 29127 | 2021-04-11 21:36:41 | MASTER-SAAO | (08h 07m 54.94s , -74d 53m 12.7s) | C | 180 | 17.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29818 SUBJECT: GRB 210411B: AstroSat CZTI detection DATE: 21/04/15 14:46:58 GMT FROM: Gaurav Waratkar at IIT Bombay P. Sawant (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), S. Gupta (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al, 2020, arxiv:2011.07067) showed detection of a long GRB 210411B, which was also detected by Fermi-GBM (GCN #29792). The source was clearly detected in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2021-04-11 13:32:55.50 UT. Quadrant D was noisy, and we exclude it from further analysis. The measured peak count rate associated with the burst is 117 (+47, -13) cts/s above the background in the combined data of four quadrants, with a total of 1409 (+320, -296) cts. The local mean background count rate was 492 (+2, -2) cts/s. Using cumulative rates, we measure a T90 of 27 (+4, -5) s. CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.