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[vsnet-grb-info 40836] GRB 251117A: Swift-XRT observations
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42768 SUBJECT: GRB 251117A: Swift-XRT observations DATE: 25/11/19 18:06:28 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , D.N. Burrows (PSU), S. Lanava (PSU) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Fermi/GBM-detected burst GRB 251117A in a series of observations tiled on the sky. The total exposure time is 6.5 ks, distributed over 7 tiles; the maximum exposure at a single sky location in the tiling was 2.0 ks. The data were collected between T0+48.9 ks and T0+81.8 ks, and are entirely in Photon Counting (PC) mode. Thirteen uncatalogued X-ray sources have been detected, however none of them is above the RASS limit or shows definitive signs of fading. Therefore, at the present time we cannot identify which, if any, is the afterglow. Details of these sources are given below: Source 1: RA (J2000.0): 331.2065 = 22h 04m 49.57s Dec (J2000.0): +5.5085 = +05d 30' 30.6" Error: 8.0 arcsec (radius, 90% conf.) Count-rate: (7.5 [+4.2, -3.1])e-3 ct s^-1 Distance: 401 arcsec from Fermi/GBM position. Flux: (2.8 [+1.5, -1.1])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 2: RA (J2000.0): 331.2121 = 22h 04m 50.90s Dec (J2000.0): +5.6862 = +05d 41' 10.4" Error: 18.7 arcsec (radius, 90% conf.) Count-rate: (4.4 [+2.7, -1.9])e-3 ct s^-1 Distance: 523 arcsec from Fermi/GBM position. Source 3: RA (J2000.0): 331.1150 = 22h 04m 27.61s Dec (J2000.0): +5.1842 = +05d 11' 03.0" Error: 8.5 arcsec (radius, 90% conf.) Count-rate: (7.0 [+4.5, -3.2])e-3 ct s^-1 Distance: 1539 arcsec from Fermi/GBM position. Source 6: RA (J2000.0): 331.1130 = 22h 04m 27.12s Dec (J2000.0): +5.7560 = +05d 45' 21.6" Error: 7.8 arcsec (radius, 90% conf.) Count-rate: (8.2 [+4.5, -3.4])e-3 ct s^-1 Distance: 947 arcsec from Fermi/GBM position. Flux: (2.8 [+1.5, -1.2])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 7: RA (J2000.0): 331.5308 = 22h 06m 07.38s Dec (J2000.0): +5.4134 = +05d 24' 48.2" Error: 6.5 arcsec (radius, 90% conf.) Count-rate: (4.9 [+2.6, -1.9])e-3 ct s^-1 Distance: 1000 arcsec from Fermi/GBM position. Source 8: RA (J2000.0): 331.7897 = 22h 07m 09.54s Dec (J2000.0): +5.6746 = +05d 40' 28.6" Error: 7.8 arcsec (radius, 90% conf.) Count-rate: (7.1 [+4.4, -3.1])e-3 ct s^-1 Distance: 1794 arcsec from Fermi/GBM position. Source 9: RA (J2000.0): 330.9021 = 22h 03m 36.49s Dec (J2000.0): +5.4483 = +05d 26' 54.0" Error: 8.3 arcsec (radius, 90% conf.) Count-rate: (7.3 [+4.4, -3.3])e-3 ct s^-1 Distance: 1491 arcsec from Fermi/GBM position. Flux: (3.5 [+2.1, -1.6])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 10: RA (J2000.0): 331.7481 = 22h 06m 59.54s Dec (J2000.0): +5.3975 = +05d 23' 51.1" Error: 8.5 arcsec (radius, 90% conf.) Count-rate: 0.0109 [+0.0053, -0.0040] ct s^-1 Distance: 1721 arcsec from Fermi/GBM position. Source 11: RA (J2000.0): 330.8986 = 22h 03m 35.66s Dec (J2000.0): +5.4101 = +05d 24' 36.5" Error: 8.6 arcsec (radius, 90% conf.) Count-rate: (8.4 [+4.7, -3.5])e-3 ct s^-1 Distance: 1549 arcsec from Fermi/GBM position. Source 12: RA (J2000.0): 330.9379 = 22h 03m 45.11s Dec (J2000.0): +5.3847 = +05d 23' 05.0" Error: 7.1 arcsec (radius, 90% conf.) Count-rate: (9.1 [+4.8, -3.5])e-3 ct s^-1 Distance: 1458 arcsec from Fermi/GBM position. Source 13: RA (J2000.0): 330.8498 = 22h 03m 23.95s Dec (J2000.0): +5.4122 = +05d 24' 44.0" Error: 9.1 arcsec (radius, 90% conf.) Count-rate: (5.8 [+4.2, -2.8])e-3 ct s^-1 Distance: 1710 arcsec from Fermi/GBM position. Source 14: RA (J2000.0): 330.7987 = 22h 03m 11.70s Dec (J2000.0): +5.6452 = +05d 38' 42.7" Error: 9.8 arcsec (radius, 90% conf.) Count-rate: (6.7 [+4.2, -3.0])e-3 ct s^-1 Distance: 1816 arcsec from Fermi/GBM position. Source 15: RA (J2000.0): 330.9250 = 22h 03m 42.01s Dec (J2000.0): +5.4456 = +05d 26' 44.0" Error: 32.4 arcsec (radius, 90% conf.) Count-rate: (5.7 [+4.1, -3.1])e-3 ct s^-1 Distance: 1416 arcsec from Fermi/GBM position. Flux: (1.79 [+1.29, -0.96])e-12 erg cm^-2 s^-1 (observed, 0.3-10 keV) The results of the XRT-team automatic analysis of the tiled XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00141. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42768. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40835] EP251118A / GRB 251118C : MASTER optical counterpart observations
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42767 SUBJECT: EP251118A / GRB 251118C : MASTER optical counterpart observations DATE: 25/11/19 17:40:22 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> Carlos Francile, Ricardo Podesta, Federico Podesta (OAFA), V. Lipunov, A.Kuznetsov, E.Gorbovskoy, G.Antipov, P.Balanutsa, I. Panchenko, N. Tiurina, K.Zhirkov, Ya.Kechin, A.Chasovnikov, V.Topolev, D. Vlasenko, Yu. Tselik, V.Senik (Lomonosov MSU, SAI, Moscow), E. Gonzalez (OAFA, San Juan Uni., Argentina), D. Buckley (SAAO, South Africa), O. Gress, N.Budnev, O.Ershova (Irkutsk State University), A. Sosnovskij (CrAO RAS), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), V.M.Pillet, R.Rebolo Lopez (The Instituto de Astrofisica de Canarias,Spain), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino, J.Martinez,A.R.Corella,L.H.Rodriguez (INAOE, Guillermo Haro Astrophysic Observatory, Mexico) MASTER-OAFA robotic telescope (Global MASTER Net [1-4],http://observ.pereplet.ru) located in Argentina started EP251118A (EP:Jiang et al. GCN 42749, Shi et al. GCN 42754, Konus-Wind: Frederiks et al. GCN 42765 as GRB 251118C) at 2025-11-19 07:57:04 UT (Lipunov et al. GCN 42755) There is optical transient MASTER OT J081239.45+105619.7 with m_OT=19.8 at 2025-11-19 07:57:04UT (calibrated by Gaia G). This optical counterpart of GRB 251118C was discovered by NOT (Malesani et al. GCN 42751) and also observed by VLT (Yadav et al. GCN 42760) and FTW (Busmann et al. GCN 42763) MASTER observations started at 45 degrees altitude (Sun_alt=-17deg) View this GCN Circular online at https://gcn.nasa.gov/circulars/42767. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40834] GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42766 SUBJECT: GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a DATE: 25/11/19 17:18:22 GMT FROM: Chenwei Wang at IHEP <cwwang(a)ihep.ac.cn> SVOM/GRM team: Chen-Wei Wang, Zheng-Hang Yu, Chao Zheng, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Maria-Grazia Bernardini (INAF-OAB) Report on behalf of the SVOM team: SVOM/GRM was triggered on-ground by a soft burst GRB 251118C at 2025-11-18T16:44:48.500 UTC (T0). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a single pulse with a T90 of 29 +22/-12 s in the 15-5000 keV band, which is also detected by Kouns-Wind (D. Frederiks et al., GCN#42765). The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251118C.png We note that the time coincidence between EP251118a (S. Q. Jiang et al., GCN#42749) and GRB 251118C suggest the association of these two events. In addition, the position of this burst, if is associated with EP251118a (RA= 123.160, DEC= 10.952, GCN#42749), is located at about 136 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-6 to T0+17 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.86 +0.17/-0.09 and the cutoff energy, parameterized as Epeak, is 44 +37/-21 keV. The event fluence (10-1000 keV) in this time interval is (7.82 +0.84/-0.83)E-06 erg/cm^2. The time-averaged spectrum is also well fitted by a power law function with a power law index of -2.4 +0.15/-0.16, corresponding to a fluence of (1.00 +0.12/-0.11)E-05 erg/cm^2. The 1s peak spectrum, measured from T0-0.5 to T0+0.5 s, if fitted by a power law function with an exponential high-energy cutoff, the power law index is -1.83 +0.25/-0.12 and the cutoff energy, parameterized as Epeak, is 64 +55/-33 keV. The flux (10-1000 keV) in this time interval is (9.47 +1.30/-1.29)E-06 erg/cm^2/s. Assuming the redshift z= 1.216 (J. An et al., GCN#42756), the localization of GRB 251118C in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251118C_amati.png And the localization in the 'Yonetoku' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251118C_yonetoku.png We caution that this analysis based on the BREAKFAST framework is very preliminary [1]. Refined analysis will be reported later. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM point of contact for this burst is: Chen-Wei Wang (IHEP)(cwwang(a)ihep.ac.cn) [1] Chen-Wei Wang et al. arXiv: 2510.15816 [astro-ph.HE] https://arxiv.org/abs/2510.15816 View this GCN Circular online at https://gcn.nasa.gov/circulars/42766. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40833] Konus-Wind detection of GRB 251118С (EP251118a)
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42765 SUBJECT: Konus-Wind detection of GRB 251118С (EP251118a) DATE: 25/11/19 16:58:51 GMT FROM: Dmitry Frederiks at Ioffe Institute <fred(a)mail.ioffe.ru> D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: A long-duration GRB 251118C was detected by Konus-Wind (KW) in the waiting mode at T0=T0(KW)~16:44:49 UT. A Bayesian block analysis of the KW data in the 20-1500 keV band reveals a ~17 sigma count rate increase in the interval from ~T0-0.5 s to ~T0+23 s. Corrected for the propagation time, the burst started ~140 s after the start time of the fast X-ray transient EP251118a (T0(EP)=16:42:29 UT; Jiang et al., GCN 42749). The burst source is located in the southern ecliptic hemisphere at a low ecliptic latitude, which is consistent with the EP251118a localization. The positional and temporal coincidence of GRB 251118C with the EP251118a supports the conclusion that both events have a common origin. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB251118C/ The time-integrated spectrum of the burst, measured from T0-0.5 s to T0+23 s, can be described by a simple power function with the photon index (2.29 ± 0.11). The total burst fluence is (5.08 ± 0.40)x10^-6 erg/cm^2, and the 2.944 s peak energy flux, measured from T0-1.96 s, is (4.84 ± 0.38)x10^-7 erg/cm^2(both in the 20 - 1500 keV energy range). Assuming the redshift z=1.216 (An et al., GCN 42756) and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the burst isotropic energy release E_iso to (2.06 ± 0.16)x10^52 erg, the isotropic peak luminosity L_iso to (4.34 ± 0.34)x10^51 erg/s. All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/42765. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40832] The EP-WXT trigger 01709248388 is likely a flaring star
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42764 SUBJECT: The EP-WXT trigger 01709248388 is likely a flaring star DATE: 25/11/19 15:27:22 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Q. C. Liu (THU), D. F. Hu, Q. J. Huang, R. Shi (PMO, CAS), F. F. Song (YNAO, CAS), S. Q. Jiang, C. C. Jin (NAO, CAS) report on behalf of the Einstein Probe team: The EP-WXT trigger 01709248388 at 2025-11-19T13:12:46 is likely a stellar flare associated with one of the two stars, RX J0423.5+0955 or RX J0423.5+0955B, that lie within the FXT error circle. The estimated flux of the flare is around 6e-11 erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 9e+31 erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/42764. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40831] The EP-WXT trigger 01709248388 is likely a flaring star
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42764 SUBJECT: The EP-WXT trigger 01709248388 is likely a flaring star DATE: 25/11/19 15:27:22 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Q. C. Liu (THU), D. F. Hu, Q. J. Huang, R. Shi (PMO, CAS), F. F. Song (YNAO, CAS), S. Q. Jiang, C. C. Jin (NAO, CAS) report on behalf of the Einstein Probe team: The EP-WXT trigger 01709248388 at 2025-11-19T13:12:46 is likely a stellar flare associated with one of the two stars, RX J0423.5+0955 or RX J0423.5+0955B, that lie within the FXT error circle. The estimated flux of the flare is around 6e-11 erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 9e+31 erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/42764. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40830] EP251118a: FTW optical and NIR observations
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42763 SUBJECT: EP251118a: FTW optical and NIR observations DATE: 25/11/19 15:14:34 GMT FROM: Malte Busmann at Ludwig-Maximilians-Universität München <m.busmann(a)physik.lmu.de> Malte Busmann (LMU), Xander J. Hall (CMU), Brendan O'Connor (CMU), Daniel Gruen (LMU), and Antonella Palmese (CMU) report: We observed the counterpart of EP251118a (Jiang et al., GCN 42749; Malesani et al., GCN 42751; Shi et al., GCN 42754; An et al., GCN 42756) with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the r, i, and J bands simultaneously for 5 x 180 s starting at 2025-11-19T04:06:56 UT (0.48 days after the trigger). The counterpart is detected in all bands. Using Legacy Survey templates for difference imaging, we measure an r-band magnitude of r = 20.56 +/- 0.04 AB mag. Our measurements are consistent with the reports by Malesani et al. (GCN 42751), Lipunov et al. (GCN 42755), Belkin et al. (GCN 42758), and Yadav et al. (GCN 42760). The magnitude is calibrated against the PS1 catalog and not corrected for Galactic extinction. We thank Michael Schmidt from the Wendelstein Observatory for obtaining these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/42763. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40829] GRB 251117A: Insight-HXMT/HE detection
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42762 SUBJECT: GRB 251117A: Insight-HXMT/HE detection DATE: 25/11/19 15:10:34 GMT FROM: Yue Wang <m18509381757(a)163.com> Yue Wang, Chen-Wei Wang, Chao Zheng, and Shao-Lin Xiong (IHEP) report on behalf of the Insight-HXMT team: At 2025-11-17T12:19:52.500 (T0), Insight-HXMT/HE detected a short-duration GRB 251117A, which is also detected by Fermi/GBM (Fermi GBM Team, GCN #42719), Fermi/LAT (A. Holzmann Airasca et. al., GCN #42729) and SVOM/GRM (Yue Wang et. al., GCN #42731). The Insight-HXMT/HE light curve mainly consists of multiple peaks with a T90 of 2.3 +2.2/-1.1 s. The 1s peak rate, measured from T0-0.05 s, is 1167 cnts/sec. Insight-HXMT/HE detected a total of 1604 counts from this burst. The Insight-HXMT/HE light curve can be found here: https://www.bursthub.cn//admin/static/hxmtgrb251117A.png All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the regular mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org View this GCN Circular online at https://gcn.nasa.gov/circulars/42762. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40828] GRB 251119A: SVOM trigger sb25111901 is not a GRB
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42761 SUBJECT: GRB 251119A: SVOM trigger sb25111901 is not a GRB DATE: 25/11/19 13:26:53 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> C. Wu (NAOC), K.X. Gong (CHO), M. Brunet (IRAP), D. Turpin, S. Schanne, D. Gotz (CEA), U. Jacob (LUPM), report on behalf of the SVOM mission team: At 2025-11-19T08:47:44 SVOM issued an alert with burst-id: sb25111901. The following circular(s) have been published regarding this event: GCN 42757, with the event labelled as GRB 251119A This event is not a GRB of astrophysical origin. After reprocessing the data with the full telemetry, this trigger is no longer considered as an astrophysical source but is due to coding noise from the Crab in the field of view. We apologize for any inconvenience this may have caused. The Burst Advocate (BA) on shift for this alert is Chao Wu: cwu(a)bao.ac.cn. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/42761. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40827] EP251118a: VLT near-infrared observation
by GCN Circulars 19 Nov '25

19 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42760 SUBJECT: EP251118a: VLT near-infrared observation DATE: 25/11/19 13:22:26 GMT FROM: muskan.yadav(a)students.uniroma2.eu Muskan Yadav, Yu-Han Yang, Massine El Kabir, Niccolò Passaleva, Nicolás Monsalves (U Rome) on behalf of the ERC BHianca team: We observed the field of EP251118a (Jiang et al., GCN 42749) with the HAWKI imager on the ESO VLT UT4 (Yepun). Observations began at 15.5 hr after the EP/WXT trigger and were carried out at an average airmass of about 1.2 in the J filter. We detect the optical counterpart (Malesani et al., GCN 42751; Belkin et al., GCN 42758) at a preliminary magnitude J ~20.35 AB mag calibrated using nearby stars in the 2MASS Catalogue (Skrutskie et al. 2006) and not corrected for Galactic extinction. We thank the staff at the VLT, for the rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/42760. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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