December 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 41014] EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
by GCN Circulars 02 Dec '25

02 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42939 SUBJECT: EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785 DATE: 25/12/02 06:18:17 GMT FROM: Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani(a)nbi.ku.dk> Z.P. Zhu (NAOC), D. B. Malesani (DAWN/NBI and Radboud), L. Izzo (INAF/OACN and DARK/NBI), A. de Ugarte Postigo (LAM), D. Xu, X. Liu, S.Q. Jiang, J. An, L.B. He (NAOC), A. Saccardi (CEA/Irfu), R. H. Rasmussen (NOT and Aarhus) report on behalf of a large collaboration: We observed the optical counterpart (Li et al., GCN 42934) of EP251202a (Zhang et al., GCN 42937), which is likely the same event of Fermi GRB 251202A (Fermi GBM team, GCN 42933), using the Nordic Optical Telescope (NOT), equipped with the ALFOSC camera and spectrograph. We obtained 10x120 s and 9x120 s exposures in the r and z bands, respectively, starting on 2025 Dec 2 at 02:51:32 UT. The afterglow is clearly detected in single images, with an AB magnitude of r = 17.27 +/- 0.01 at a mid time of 1.05 hr after the trigger. A sequence of 3 spectra by 1200 s each was then acquired using grism #4, covering the wavelength range 3500-9500 AA. Our first spectrum started on 2025 Dec 2.156 UT (1.93 hr after the EP/WXT trigger). Continuum is detected across the whole wavelength range. A spectral break is detected around 4610 AA, and the onset of the forest is seen blueward of this wavelength. We match existing features to a low-column density Lyman alpha and C IV (unresolved) at z = 2.785, which we believe to be the redshift of the burst. Intervening systems are also seen in Lyman alpha and C IV at z = 2.450 and 2.356. We acknowledge the use of the grbspec.eu tool to analyse this spectrum. View this GCN Circular online at https://gcn.nasa.gov/circulars/42939. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41013] Fermi GRB 251202A: Global MASTER-Net observations report
by GCN Circulars 02 Dec '25

02 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42938 SUBJECT: Fermi GRB 251202A: Global MASTER-Net observations report DATE: 25/12/02 03:30:34 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-SAAO robotic telescope [1] located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 251202A ( Fermi GBM team, GCN 42933) errorbox 570 sec after notice time and 604 sec after trigger time at 2025-12-02 02:00:56 UT, with upper limit up to 18.8 mag. Observations started at twilight. The observations began at zenith distance = 76 deg. The sun altitude is -15.8 deg. The galactic latitude b = 31 deg., longitude l = 177 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3057770 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 634 | 2025-12-02 02:00:56 | MASTER-SAAO | (07h 56m 46.47s , +43d 37m 13.0s) | C | 60 | 17.7 | 694 | 2025-12-02 02:00:56 | MASTER-SAAO | (07h 56m 46.46s , +43d 37m 13.0s) | C | 180 | 18.6 | Coadd 634 | 2025-12-02 02:00:56 | MASTER-SAAO | (07h 59m 07.79s , +43d 21m 09.1s) | C | 60 | 18.0 | 694 | 2025-12-02 02:00:56 | MASTER-SAAO | (07h 59m 07.80s , +43d 21m 09.1s) | C | 180 | 18.8 | Coadd Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/42938. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41012] EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
by GCN Circulars 02 Dec '25

02 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42937 SUBJECT: EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient DATE: 25/12/02 03:28:01 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y. J. Zhang (THU), R. D. Liang (NAOC) Z. M. Wang (BNU), Y. Wu (NJU), H. N. Yang, H. Sun (NAOC) on behalf of the Einstein Probe (EP) team: We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP251202a. The transient triggered EP-WXT (ID: 01709249064) at 2025-12-02T01:49:15 (UTC). The WXT position of the source is R.A. = 122.121 deg, DEC = 40.600 deg (J2000) with an uncertainty of 3 arcmin in radius (90% C.L. statistical and systematic). The trigger time and the position of the transient is consistent with that of GRB 251202A detected by Fermi/GBM (GCN 42933). We performed a follow-up observation with the Follow-up X-ray Telescope (FXT), starting at 2025-12-02T02:09:51 (UTC), about 20 minutes after the trigger. Within the WXT error circle, an uncatalogued X-ray source was detected at R.A. = 122.1190 deg, DEC = 40.6125 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic). The position is 12 arcsec from the optical counterpart reported by Las Cumbres Observatory (Li et al., GCN 42934). Further information will be updated when the telemetry data is received. 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/42937. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41011] GRB 251201B: Swift-XRT refined Analysis
by GCN Circulars 02 Dec '25

02 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42936 SUBJECT: GRB 251201B: Swift-XRT refined Analysis DATE: 25/12/02 03:23:04 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), D.N. Burrows (PSU), S. Lanava (PSU), S. Dichiara (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), C. Salvaggio (INAF-OAB) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 6.3 ks of XRT data for GRB 251201B, from 86 s to 23.3 ks after the trigger. The data comprise 362 s in Windowed Timing (WT) mode (the first 6 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The late-time light curve (from T0+6.3 ks) can be modelled with a power-law decay with a decay index of alpha=1.6 (+/-0.3). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.40 (+/-0.04). The best-fitting absorption column is 2.30 (+/-0.12) x 10^21 cm^-2, in excess of the Galactic value of 1.8 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.93 (+0.16, -0.15) and a best-fitting absorption column of 10.0 (+4.5, -4.0) x 10^20 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.5 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 10.0 (+4.5, -4.0) x 10^20 cm^-2 Galactic foreground: 1.8 x 10^20 cm^-2 Excess significance: 3.4 sigma Photon index: 1.93 (+0.16, -0.15) If the light curve continues to decay with a power-law decay index of 1.6, the count rate at T+24 hours will be 3.5 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-13 (1.5 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/01418729. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42936. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41010] IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 02 Dec '25

02 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42935 SUBJECT: IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube DATE: 25/12/02 02:50:34 GMT FROM: Yuhua Yao at IceCube/UW-Madison <yyao255(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-251130A (https://gcn.nasa.gov/circulars/42909) in a time range of 1000 seconds centered on the alert event time (2025-11-30 17:45:10.690 UTC to 2025-11-30 18:01:50.690 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-251130A. We report a p-value of 1.00 in this time window. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, ranges from 4.2e-01 to 5.5e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-251130A in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 4e+02 GeV and 3e+05 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2025-11-29 17:53:30.690 UTC to 2025-12-01 17:53:30.690 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, ranges from 4.3e-01 to 5.6e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-251130A in a 2 day time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) View this GCN Circular online at https://gcn.nasa.gov/circulars/42935. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41009] The EP-WXT trigger 01709249064: Las Cumbres discovery of the optical counterpart
by GCN Circulars 02 Dec '25

02 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42934 SUBJECT: The EP-WXT trigger 01709249064: Las Cumbres discovery of the optical counterpart DATE: 25/12/02 02:44:37 GMT FROM: Wenxiong Li at NAOC <liwenxiong1992(a)gmail.com> Wenxiong Li, Runduo Liang (NAOC), Iair Arcavi (TAU), Ido Keinan (TAU), David Sand (U of Arizona) We observed the position of The EP-WXT trigger 01709249064 with a Las Cumbres 1m telescope at Teide Observatory, Tenerife, 18 mins after the Einstein Probe WXT trigger. We took 2x300s exposures in the broad optical w band. We find a uncataloged source at RA=122.1143 Dec=40.6123 within the EP/WXT error circle and measure the following preliminary photometry calibrated to the r band: MJD 61011.089 Mag 15.6 We find a faint red likely extended source at this position in Legacy Survey data (https://www.legacysurvey.org/viewer) Additional followup is encouraged. View this GCN Circular online at https://gcn.nasa.gov/circulars/42934. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41008] GRB 251202A: Fermi GBM Final Real-time Localization
by GCN Circulars 02 Dec '25

02 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42933 SUBJECT: GRB 251202A: Fermi GBM Final Real-time Localization DATE: 25/12/02 02:01:27 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 01:50:52 UT on 2 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251202A (trigger 786333057.306028 / 251202077). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 120.3, Dec = 43.5 (J2000 degrees, equivalent to J2000 08h 01m, 43d 30'), with a statistical uncertainty of 2.8 degrees. The angle from the Fermi LAT boresight is 70.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251202077/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251202077/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251202077/… View this GCN Circular online at https://gcn.nasa.gov/circulars/42933. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41007] GRB 251201A: SVOM/GRM observation of a burst
by GCN Circulars 02 Dec '25

02 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42932 SUBJECT: GRB 251201A: SVOM/GRM observation of a burst DATE: 25/12/02 01:33:14 GMT FROM: Yue Wang <m18509381757(a)163.com> SVOM/GRM team: Yue Wang, Chen-Wei Wang, Wen-Jun Tan, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Maria Grazia BERNARDINI (INAF-OAB, LUPM) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by GRB 251201A (SVOM trigger reference: sb25120107) at 2025-12-01T04:37:04.500 (T0), which is also detected by MAXI/GSC (MAXI team, GCN #42913) and GECAM-B. With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a multi-pulses followed by a possible flare with a total T90 of 39.3 +5.1/-1.8 s in the 15-5000 keV band, the T90 of the main emission is 4.1 +0.4/-0.2 s. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251201A.png In addition, the position of this burst, as determined by MAXI/GSC (RA=309.032, DEC=30.413, GCN #42913), is located at about 59 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-3 to T0+40 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.55 +0.15/-0.11 and the cutoff energy, parameterized as Epeak, is 352 +308/-144 keV. The event fluence (10-1000 keV) in this time interval is (5.32 +0.54/-0.58)E-06 erg/cm^2. The 1s peak spectrum, measured from T0-0.3 to T0+0.7 s, if fitted by a power law function with an exponential high-energy cutoff, the power law index is -0.51 +0.11/-0.12 and the cutoff energy, parameterized as Epeak, is 154 +11/-9 keV. The flux (10-1000 keV) in this time interval is (1.71 +0.08/-0.07)E-06 erg/cm^2/s. The localization of GRB 251201A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251201A_amati.png The localization of GRB 251201A in the 'Yonetoku' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251201A_yonetoku.png 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/GRM point of contact for this burst is: Yue Wang (IHEP) (yuewang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/42932. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41006] GRB 251201B: SVOM/VT optical fading
by GCN Circulars 02 Dec '25

02 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42931 SUBJECT: GRB 251201B: SVOM/VT optical fading DATE: 25/12/02 00:45:58 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> H.L. Li, L.P. Xin, Y. L. Qiu, C. Wu, Z. H. Yao, Y. N. Ma, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. R. Xu, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA) report on behalf of the SVOM/VT team. SVOM/VT performed ToO observation to the field of GRB 251201B (Fermi GBM team, GCN 42923; Moss et al., GCN 42924; Osborne et al., GCN 42927; Goyal et al., GCN 42925). The observation stared at 2025-12-01T17:48:58 UTC, I.e., 1.4 minutes post trigger in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. The optical counterpart (Cerón et al., GCN 42929;Buckley et al., GCN 42930) was detected Within the error box of Swift-UVOT (Moss et al., GCN 42924) and Swift-XRT (Osborne et al., GCN 42927). The position is at R.A., Dec. = 6.39414, -44.23374 degrees, equivalent to: R.A. (J2000) = 0:25:34.59 Dec. (J2000) = -44:14:01.46 with an uncertainty of 0.5 arcsec. The measurements in AB magnitude without correction for Galactic extinction are given below: Mid_time Band Exposure Time Magnitude (AB) 1.40 hours VT_B 70 sec 18.56+/-0.03 mag 1.40 hours VT_R 70 sec 18.08+/-0.03 mag 3.04 hours VT_B 70 sec 19.46+/-0.04 mag 3.04 hours VT_R 70 sec 18.97+/-0.04 mag It was fading with a slope of about -1.0 with a single power law. 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. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/42931. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41005] Swift GRB 251201B : MASTER optical counterpart detection
by GCN Circulars 01 Dec '25

01 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42930 SUBJECT: Swift GRB 251201B : MASTER optical counterpart detection DATE: 25/12/01 23:18:16 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> D.Buckley (SAAO), V.M. Lipunov (Lomonosov MSU), A.Kuznetsov, I.Panchenko, G.Antipov, P.Balanutsa, K.Zhirkov, V.Senik, N. Tiurina, Ya.Kechin, A.Chasovnikov, D.Vlasenko, E.Gorbovskoy, Yu.Tselik(Lomonosov MSU, SAI, Moscow), O.A.Gress, N.M.Budnev, O.Ershova (Irkutsk State University), R. Podesta, C.Francile, F. Podesta, E. Gonzalez (OAFA, San Juan Uni.,Argentina); A. Sosnovskij (CrAO RAS), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysic Observatory, Mexico) V.M.Pillet, R.Rebolo Lopez (The Instituto de Astrofisica de Canarias,Spain), MASTER-SAAO robotic telescope of MASTER Global Robotic Net (Lipunov et al. [1-4], http://observ.pereplet.ru ), started Swift GRB 251201B (Moss et al GCN 42924, Osborne et al. GCN 42927) inspect at 2025-12-01 22:00:57 UT (20067s after trigger time), Lipunov et al. GCN 42929 There is optical counterpart MASTER OT J002534.28-441352.2 at Swift UVOT position (Moss et al. GCN 42924) with unfiltered m_OT~20.4m at summary image at 22:00:57 UT (420s exposition, mlim=21m). Real time updated cover map and OT position are available here: https://master.sai.msu.ru/site/master2/observ.php?id=3054567 Observation and reduction will continue. [1] Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L [2] Lipunov et al. 2022, Universe, Vol. 8(5), id.271 [3] Lipunov et a. 2019, ARep, vol.63, 293 [4] Lipunov V., Kornilov V., Gorbovskoy E., Tiurina N., Kuznetsov A. 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics,Lomonosov MSU PRESS, 591pp. http://www.pereplet.ru/lipunov/625.html#625 View this GCN Circular online at https://gcn.nasa.gov/circulars/42930. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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