//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30323 SUBJECT: GRB 210626A: Fermi GBM Final Real-time Localization DATE: 21/06/26 08:26:33 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 08:16:15 UT on 26 Jun 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210626A (trigger 646388180.992174 / 210626345). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 216.0, Dec = -4.2 (J2000 degrees, equivalent to J2000 14h 24m, -4d 12'), with a statistical uncertainty of 3.9 degrees. The angle from the Fermi LAT boresight is 76.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210626345/quicklook/glg_skymap_all_bn210626345.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/bn210626345/quicklook/glg_healpix_all_bn210626345.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210626345/quicklook/glg_lc_medres34_bn210626345.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30325 SUBJECT: GRB 210626A: Swift/BAT-GUANO detection and arcminute localization DATE: 21/06/26 15:32:38 GMT FROM: Aaron Tohuvavohu at U Toronto Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Jamie A. Kennea (PSU), Gayathri Raman (PSU) report: Swift/BAT did not trigger on GRB 210626A (T0: 2021-06-26 08:16:15.9 UTC, Fermi/GBM GCN 30323). The Fermi/GBM notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The burst is detected in BAT with a duration greater than 20 seconds. The burst occurred during a Swift slew. Using the normal BAT imaging technique, we find the location for the GRB with an SNR of 7.6. The BAT position is RA, Dec = 221.6199, -1.1512 deg which is RA(J2000) = 14h 46m 28.78s Dec(J2000) = -1d 09′ 4.3″ with an estimated uncertainty of 5 arcmin. This position is consistent with the Ferm/GBM localization (GCN 30323). XRT and UVOT follow-up has been requested. Results of follow-up observations will be reported in future circulars. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30326 SUBJECT: GRB 210626A: Swift ToO observations DATE: 21/06/26 16:30:23 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 Swift/BAT-GUANO GRB 210626A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021453 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 Swift/BAT-GUANO 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: 30327 SUBJECT: Fermi GRB 210626A: Global MASTER-Net observations report DATE: 21/06/26 21:16:42 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-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 of the Fermi GRB 210626A ( Fermi GBM team, GCN 30323) errorbox 45371 sec after notice time and 45494 sec after trigger time at 2021-06-26 20:54:30 UT, with upper limit up to 18.5 mag. Observations started at twilight. The observations began at zenith distance = 33 deg. The sun altitude is -10.6 deg. The galactic latitude b = 51 deg., longitude l = 343 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1645256 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 45524 | 2021-06-26 20:54:30 | MASTER-IAC | (14h 31m 35.31s , -04d 23m 21.9s) | C | 60 | 17.3 | 45524 | 2021-06-26 20:54:30 | MASTER-IAC | (14h 23m 30.29s , -04d 17m 54.2s) | C | 60 | 16.8 | 45604 | 2021-06-26 20:55:49 | MASTER-IAC | (14h 29m 54.51s , -02d 30m 25.6s) | C | 60 | 17.3 | 45604 | 2021-06-26 20:55:49 | MASTER-IAC | (14h 21m 50.29s , -02d 24m 57.4s) | C | 60 | 17.1 | 45684 | 2021-06-26 20:57:09 | MASTER-IAC | (14h 19m 03.53s , -06d 19m 19.7s) | C | 60 | 17.5 | 45684 | 2021-06-26 20:57:09 | MASTER-IAC | (14h 10m 57.01s , -06d 13m 53.3s) | C | 60 | 17.3 | 45763 | 2021-06-26 20:58:29 | MASTER-IAC | (14h 16m 27.27s , -04d 25m 15.0s) | C | 60 | 17.6 | 45763 | 2021-06-26 20:58:29 | MASTER-IAC | (14h 08m 22.21s , -04d 19m 48.0s) | C | 60 | 17.5 | 45843 | 2021-06-26 20:59:49 | MASTER-IAC | (14h 34m 23.49s , -06d 17m 53.6s) | C | 60 | 17.7 | 45843 | 2021-06-26 20:59:49 | MASTER-IAC | (14h 26m 16.98s , -06d 12m 26.1s) | C | 60 | 17.5 | 45924 | 2021-06-26 21:01:09 | MASTER-IAC | (14h 29m 01.44s , -00d 37m 28.8s) | C | 60 | 18.1 | 45924 | 2021-06-26 21:01:09 | MASTER-IAC | (14h 20m 57.52s , -00d 32m 00.3s) | C | 60 | 17.9 | 46004 | 2021-06-26 21:02:30 | MASTER-IAC | (14h 14m 40.67s , -02d 29m 37.6s) | C | 60 | 18.1 | 46004 | 2021-06-26 21:02:30 | MASTER-IAC | (14h 06m 36.35s , -02d 24m 10.3s) | C | 60 | 17.5 | 46084 | 2021-06-26 21:03:50 | MASTER-IAC | (14h 22m 43.90s , -08d 12m 29.4s) | C | 60 | 17.9 | 46084 | 2021-06-26 21:03:50 | MASTER-IAC | (14h 14m 35.23s , -08d 07m 03.1s) | C | 60 | 17.7 | 46164 | 2021-06-26 21:05:10 | MASTER-IAC | (14h 13m 45.82s , -00d 35m 27.8s) | C | 60 | 18.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30329 SUBJECT: GRB 210626A: Swift-XRT afterglow detection DATE: 21/06/27 00:08:12 GMT FROM: Aaron Tohuvavohu at U Toronto M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Swift/BAT-GUANO-detected burst GRB 210626A (Aaron Tohuvavohu et al. GCN Circ. 30325), collecting 1.4 ks of Photon Counting (PC) mode data between T0+29.7 ks and T0+31.1 ks. An uncatalogued X-ray source is detected and is above the 2SXPS 3-sigma upper limit at this position, and is therefore likely the GRB afterglow. Using 1180 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 221.52429, -1.15625 which is equivalent to: RA (J2000): 14h 46m 05.83s Dec(J2000): -01d 09' 22.5" with an uncertainty of 5.7 arcsec (radius, 90% confidence). This position is 5.7 arcmin from the Swift/BAT-GUANO position. We cannot determine at the present time whether the source is fading. The results of the XRT-team automatic analysis of the likely afterglow are at https://www.swift.ac.uk/ToO_GRBs/00021453/Source1.php. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021453. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30336 SUBJECT: GRB 210626A: GIT optical upper limit DATE: 21/06/28 08:53:15 GMT FROM: Harsh Kumar at Indian Inst of Tech,Bombay H. Kumar(IITB), J. Stanzin (IAO), V. Bhalerao(IITB), G. C. Anupama(IIA), S. Barway(IIA) report on behalf of the GIT team: We observed GRB 210626A detected by Fermi GBM (GCN #30323) with 0.7 m GROWTH-India Telescope (GIT). The GRB was also detected by Swift/BAT-GUANO (GCN #30325) and later on, Swift-XRT detected X-ray afterglow candidate (GCN #30329). We obtained exposures in the r' filter. We did not detect any new source in our stacked image within the 5.7 arcsec circle, around RA: 14:46:05.83, Dec: -01:09:22.5 (GCN #30329). Further, we did not find any new source within the 5 arcmin region identified by BAT localisation (GCN #30325). The obtained upper limit follow as: ------------------------------------------------------------------------- JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) | ------------------------------------------------------------------------- 2459392.2353 | 9.37 | 2 x 300 (stacked) | r' | > 20.5 | ------------------------------------------------------------------------- The magnitudes are calibrated against PanSTARRS (Flewelling et al., 2018) and not corrected for Galactic extinction. The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30337 SUBJECT: GRB 210626A: Ondrejov D50 optical limit DATE: 21/06/28 09:59:16 GMT FROM: Martin Jelinek at Astro.Inst-AVCR,Ondrejov Martin Jelinek, Jan Strobl, Rene Hudec and Cyril Polasek (ASU CAS Ondrejov, CZ), report: We observed the Swift-improved localization (Tohuvavohu et al. GCN 30325, Perri et al. GCN 30329) of the GBM-detected GRB 210626A (Fermi GBM Team, GCN 30323) with the 50 cm robotic telescope (D50) of Ondrejov observatory in Czech Republic. We obtained a set of 120 s Sloan-i' exposures starting at 21:10 UT, i.e. 0.5386 d after the initial trigger. The magnitude limit of our 34 x 120 s image with a mean time T-T0 0.5626 d post burst is i' > 21.2 (AB). The XRT (Perri et al. GCN 30329) error box does not appear completely clean in the image, there is a noise fluctuation or possibly a candidate at the level of i' = 21.3 +/- 0.4. While we mention this, we also note that this is in a light halo of a nearby bright star, so artefacts of this kind may not be excluded. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30339 SUBJECT: GRB 210626A: CAHA 2.2m telescope optical limit DATE: 21/06/28 10:43:38 GMT FROM: Youdong HU at IAA-CSIC Y.-D. Hu, T.-R. Sun, E. Fernandez-Garcia, A. J. Castro-Tirado, M. D. Caballero-Garcia, M. A. Castro Tirado (IAA-CSIC), A. Fernandez and I. Hermelo (CAHA) on behalf of a larger collaboration, report: Following the detection of GRB 210626A by both Swift (Tohuvavohu et al. GCNC 30325) and Fermi (Fermi/GBM team GCNC 30323), we triggered the 2.2m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almeria, Spain), gathering images starting on June 27, 20:37 UT (i.e. 1.5 day post trigger). On the co-added image (i-band, 3x180s), no optical transient down to 22.4 mag is detected at the X-ray afterglow candidate position reported by Swift/XRT (Evans et al. GCNC 30326, Perri et al. GCNC 30329). We thank the staff at Calar Alto observatory for their excellent support. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30340 SUBJECT: GRB 210626A: Fermi GBM observation DATE: 21/06/28 15:25:08 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 08:16:15.99 UT on 26 June 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210626A (trigger 646388180 / 210626345), which was also detected by the Swift/BAT-GUANO (Tohuvavohu et al. 2021, GCN 30325). The Fermi GBM Final Real-time Localization is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 73 degrees. The GBM light curve shows a singel pulse with a duration (T90) of about 34 s (50-300 keV). The time-averaged spectrum from T0-5.632 s to T0+29.184 s is best fit by a Band function with Epeak= 86 +/- 18 keV, alpha = -1.21 +/- 0.16 and beta = -2.25 +/- 0.24 The event fluence (10-1000 keV) in this time interval is (5.1 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+5.696 s in the 10-1000 keV band is 3.40 +/- 0.24 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: 30341 SUBJECT: GRB 210626A: Swift/XRT afterglow confirmation DATE: 21/06/28 19:07:34 GMT FROM: Antonino D'Ai at IASF-PA Antonino D'Aì (INAF-IASFPA) & Aaron Tohuvavohu (Uni. Toronto) report on behalf of the Swift-XRT team: Swift-XRT has performed further follow-up observations of the Fermi/GBM (von Kienlin GCN 30340) and Swift/BAT-GUANO detected burst GRB 210626A (Tohuvavohu et al., GCN Circ. 30325), collecting 7.9 ks of Photon Counting (PC) mode data between T0+29.7 ks and T0+143 ks. The X-ray source detected in the first 1.4 ks of data as possible GRB afterglow candidate (Perri et al. GCN 30329) has faded more than 3 sigma in the latest observation, and it is thus confirmed as the X-ray afterglow of the burst. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/xrt_curves/00021453/. This circular is an official product of the Swift-XRT team.