//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29988 SUBJECT: GRB 210511B: Fermi GBM Final Real-time Localization DATE: 21/05/11 11:36:59 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 11:26:39 UT on 11 May 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210511B (trigger 642425204.260366 / 210511477). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 316.2, Dec = 61.7 (J2000 degrees, equivalent to J2000 21h 04m, 61d 42'), with a statistical uncertainty of 1.0 degrees. The angle from the Fermi LAT boresight is 49.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210511477/quicklook/glg_skymap_all_bn210511477.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/bn210511477/quicklook/glg_healpix_all_bn210511477.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210511477/quicklook/glg_lc_medres34_bn210511477.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29989 SUBJECT: GRB 210511B: BALROG localization (Fermi Trigger 642425204 / GRB 210511477) DATE: 21/05/11 11:47:05 GMT FROM: Jochen Greiner at MPE,Garching F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 642425204 at 11:26:39 on 11 May 2021 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position (1 sigma statistical errors) is: RA(2000.0) = 314.1+/-1.4 deg Decl.(2000.0) = 56.3+/-0.6 deg We estimate an additional systematic error of 1 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB210511477/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB210511477/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB210511477/json //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29990 SUBJECT: GRB 210511B: GECAM detection DATE: 21/05/11 14:50:20 GMT FROM: Ce Cai at IHEP C. Cai, S. L. Xie, Y. Huang, S. L. Xiong, S. Xiao, Y. Zhao, J. C. Liu, C. Y. Li, Y. Q. Zhang, W. C. Xue, C. Zheng, Z. W. Guo, X. Y. Zhao, Z. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, J. J. He, B. Li, C. Li, J. H. Li, Q. X. Li, X. B. Li, X. Q. Li, Y. G. Li, X. H. Liang, J. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, F. J. Lu, Q. Luo, X. Ma, G. Ou, W. X. Peng, R. Qiao, D. L. Shi, J. Y. Shi, L. M. Song, X. Y. Song, G. X. Sun, X. L. Sun, Y. L. Tuo, C. W. Wang, J. Z. Wang, P. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, M. Yao, Q. B. Yi, B. X. Zhang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang, K. Zhang, P. Zhang, S. N. Zhang, Z. Zhang, S. Y. Zhao, S. J. Zheng, X. Zhou (IHEP), report on behalf of GECAM team: During the commissioning phase, GECAM-B was triggered by a long GRB 210511B at 2021-05-11T11:26:40.600 UTC (denoted as T0), which was also observed by Fermi/GBM (GCN #29988). GECAM alert data was promptly downlinked to the ground through the short message service of BeiDou Navigation Satellite System (BDS). The time latency of the first BeiDou message relative to the trigger time is about 1 minute. According to the BDS alert data, this burst mainly consists of a single pulse with a duration of about 10s. An automatic on-ground localization was calculated using the light curves and spectrum. Although the in-flight calibration of energy response and localization has not been finalized yet, GECAM-B localized this burst to the following position (J2000): ra: 317.99 deg dec: 59.53 deg err: 3.19 deg (statistical only) The current systematic error of location is estimated to be several degrees which could be minimized by the ongoing calibration. This position is consistent with the Fermi GBM team localization (GCN 29988) within the error. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_all_combine_74431600.png As the detailed science data are downloaded, all analyses would be improved. Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29991 SUBJECT: GRB 210511B: AGILE detection DATE: 21/05/11 17:11:19 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), V. Fioretti (INAF/OAS-Bologna), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, G. Piano (INAF/IAPS), F. Lucarelli, C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), A. Bulgarelli, A. Di Piano, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite detected the long GRB 210511B at T0 = 2021-05-11 11:26:37 s (UTC), reported by Fermi/GBM (GCN #29988) and GECAM (GCN #29990). The burst is visible in the AGILE scientific ratemeters of the SuperAGILE (SA; 20-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV) detectors. The event lasted ~12 s and released a total number of 2120 counts in the SA detector (above a background rate of 64 Hz), 15630 counts in the MCAL detector (above a background rate of 1260 Hz), and 48375 counts in the AC detector (above a background rate of 3865 Hz). The AGILE ratemeter light curves can be found at http://www.agilescienceapp.it/notices/GRB210511_AGILE_RM.png . Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29992 SUBJECT: Fermi GRB 210511B: Global MASTER-Net observations report DATE: 21/05/11 18:31:20 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 210511B ( Fermi GBM team, GCN 29988) errorbox 24287 sec after notice time and 24402 sec after trigger time at 2021-05-11 18:13:21 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 68 deg. The sun altitude is -17.1 deg. The galactic latitude b = 10 deg., longitude l = 99 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1611119 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 24492 | 2021-05-11 18:13:21 | MASTER-Kislovodsk | (21h 04m 20.43s , +61d 44m 35.3s) | C | 180 | 17.6 | 24493 | 2021-05-11 18:13:21 | MASTER-Kislovodsk | (21h 04m 10.88s , +61d 20m 40.1s) | C | 180 | 18.0 | 24693 | 2021-05-11 18:16:41 | MASTER-Kislovodsk | (21h 04m 27.56s , +61d 43m 35.1s) | C | 180 | 17.5 | 24693 | 2021-05-11 18:16:41 | MASTER-Kislovodsk | (21h 04m 18.29s , +61d 19m 37.6s) | C | 180 | 18.0 | 24893 | 2021-05-11 18:20:02 | MASTER-Kislovodsk | (20h 54m 20.98s , +62d 42m 45.4s) | C | 180 | 17.4 | 24893 | 2021-05-11 18:20:02 | MASTER-Kislovodsk | (20h 54m 12.62s , +62d 18m 48.3s) | C | 180 | 17.9 | 25093 | 2021-05-11 18:23:22 | MASTER-Kislovodsk | (20h 54m 27.35s , +62d 43m 01.4s) | C | 180 | 17.4 | 25093 | 2021-05-11 18:23:22 | MASTER-Kislovodsk | (20h 54m 19.40s , +62d 19m 03.9s) | C | 180 | 17.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29996 SUBJECT: GRB 210511B: Fermi GBM observation DATE: 21/05/11 21:37:39 GMT FROM: Elisabetta Bissaldi at INFN,Bari E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 11:26:39.26 UT on 11 May 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210511B (trigger 642425204 / 210511477), which was also detected by GECAM (Cai et al., GCN 29990) and by AGILE (Ursi et al., GCN 29991). The Fermi GBM Final Real-time Localization was reported in GCN 29988. The angle from the Fermi LAT boresight at the GBM trigger time is 49 degrees. The GBM light curve consists of a bright emission episode with a duration (T90) of about 6 s (50-300 keV). The time-averaged spectrum from T0 to T0+8 s is best fit by a Band function with Epeak = 128 +/- 5 keV, alpha = -0.72 +/- 0.04, and beta = -2.47 +/- 0.10. The event fluence (10-1000 keV) in this time interval is (1.04 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+4.2 s in the 10-1000 keV band is 23.3 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29998 SUBJECT: GRB 210511B: DDOTI Upper Limits on the Afterglow DATE: 21/05/12 00:14:52 GMT FROM: Kin O. C. L. Mendoza at Instituto de Astronoma, UNAM Océlotl Lopez (UNAM), Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Simone Dichiara (GSFC/UMD), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Diego Gonzalez (UNAM), Margarita Pereyra (UNAM), Srihari Ravi (ASU), and Eleonora Troja (GSFC/UMD) report: We observed the field of the Fermi - GBM event GRB 210511B (Fermi Collaboration, GCN Circ. 29988) with the DDOTI wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Martir ( http://ddoti.astroscu.unam.mx) from 2021-05-11 11:49:26 to 12:01:38 UTC (0.38 to 0.58 hours after the trigger) and obtained 6 minutes of exposure in the w filter. The images were obtained after the astronomical twilight. We observed a region covering approximately 14 degrees in RA and 10 degrees in declination, with a 2 x 1 grid, including the entire initial uncertainty region distributed in the GCN Notice (Fermi Collaboration, GCN Circ. 29988) Comparing to the Pan-STARRS DR1 catalog, we detect no uncatalogued point sources to a 10-sigma limiting magnitude of w = 18.39. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Martir. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30002 SUBJECT: IPN triangulation of GRB 210511B DATE: 21/05/12 18:15:02 GMT FROM: Dmitry Svinkin at Ioffe Institute K. Hurley, on behalf of the IPN, I. G. Mitrofanov, D. V. Golovin, A. S. Kozyrev, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, D. Svinkin, S. Golenetskii, D. Frederiks, A. Ridnaia, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 210511B (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 29988; Bissaldi and Meegan, GCN Circ. 29996; BALROG localization: Kunzweiler et al., GCN Circ. 29989; GECAM detection: Cai et al., GCN Circ. 29990; AGILE detection: Ursi et al., GCN Circ. 29991) was detected by Fermi (GBM trigger 642425204), Konus-Wind, Mars-Odyssey (HEND), INTEGRAL (SPI-ACS), AGILE and GECAM-B at about 41199 s UT (11:26:39). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 312.914 (20h 51m 39s) +58.375 (+58d 22' 31") Corners: 306.385 (20h 25m 33s) +59.894 (+59d 53' 39") 306.250 (20h 25m 00s) +60.029 (+60d 01' 45") 318.903 (21h 15m 37s) +56.519 (+56d 31' 10") 318.984 (21h 15m 56s) +56.371 (+56d 22' 16") --------------------------------------------- The error box area is 2687 sq. arcmin, and its maximum dimension is 7.6 deg (the minimum one is 6.0 arcmin). The Sun distance was 75 deg. This box may be improved. This error box is consistent with, but reduces the areas of, the Fermi (RoboBA and BALROG), and GECAM localizations. A triangulation map is posted at http://www.ioffe.ru/LEA/GRBs/GRB210511_T41201/IPN The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30007 SUBJECT: Konus-Wind detection of GRB 210511B DATE: 21/05/13 20:48:20 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, S. Golenetskii, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, report: The long-duration GRB 210511B (Fermi GBM detection: Fermi GBM team, GCN 29988; Bissaldi and Meegan, GCN 29996; BALROG localization: Kunzweiler et al., GCN 29989; GECAM detection: Cai et al., GCN 29990; AGILE detection: Ursi et al., GCN 29991; IPN triangulation: Hurley et al., GCN 30002) triggered Konus-Wind at T0=41201.35 s UT (11:26:41.350). The burst light curve shows a multi-peaked structure which starts at ~T0-1.7 s and has a total duration of ~6 s. The emission is seen up to ~4 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB210511_T41201/ As observed by Konus-Wind, the burst had a fluence of 1.10(-0.15,+0.18)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+0.512 s, of 4.76(-1.24,+1.34)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 4 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.98(-0.15,+0.18), the high energy photon index beta = -2.48(-0.43,+0.23), the peak energy Ep = 154(-22,+25) keV (chi2 = 86/71 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.