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[vsnet-grb-info 41125] GRB 251208B: GROWTH-India Telescope optical upper limits
by GCN Circulars 09 Dec '25

09 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43045 SUBJECT: GRB 251208B: GROWTH-India Telescope optical upper limits DATE: 25/12/09 09:02:28 GMT FROM: V. Swain at IIT Bombay <vishwajeet.s(a)iitb.ac.in> A. Kumar, T. Mohan, V.Swain, S. Patil, A.P. Saikia, V. Bhalerao (IITB), G.C. Anupama, S. Barway (IIA) and K. Angail (IAO) report on behalf of the GIT team: We observed the field of Fermi GBM transient (Fermi GBM Team, GCN 43028), with 0.7m GROWTH-India Telescope (GIT). We started the observation at 2025-12-08T23:43:57 UT, i.e., about 13.4 hours after the Fermi GBM Trigger. Exposures were obtained in r' and i' filters. We did not detect any transient in our images within the Fermi-LAT on-ground localization region (Bissaldi et al., GCN 43034). Additionally, we checked the source 1 and 5 of Swift-XRT ToO observations (Evans at al., GCN 43035), and did not detect any optical counterpart at their respective position and uncertainty. The photometric upper limits are as follows: | MJD (mid) | Filter | tmid-t0 (hrs) | Exposure Time (sec) | Upper limit (AB) | | ------------ | ------ | ------------- | ------------------- | ---------------- | | 61018.007928 | r' | 13.90 | 3 x 360 | 20.6 | | 61018.020746 | i' | 14.21 | 2 x 360 | 17.4 | The measurement is calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction. The GROWTH India Telescope (GIT; Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports the operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/. View this GCN Circular online at https://gcn.nasa.gov/circulars/43045. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41124] GRB 251205A: J-band detection with WINTER
by GCN Circulars 09 Dec '25

09 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43044 SUBJECT: GRB 251205A: J-band detection with WINTER DATE: 25/12/09 02:23:58 GMT FROM: Geoffrey Mo at Caltech / Carnegie Observatories <gmo(a)mit.edu> Geoffrey Mo (Caltech/Carnegie), Tomas Ahumada (NOIRLab), Benjamin Schneider (LAM), Viraj Karambelkar (Columbia), Robert Stein (UMD), Danielle Frostig (CfA), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report: We observed the field of GRB 251205A (Lanava et al., GCN 43005; Beardmore et al., GCN 43007; Dichiara et al., GCN 43017; Krimm et al., GCN 43018) in the near-infrared J band with the Palomar 1-m telescope, equipped with the 1.2-square degree WINTER camera (Lourie et al. 2020, Frostig et al. 2024). Observations began at 2025-12-06T10:27:54 UTC in the J band (~10.8 hours after the GRB trigger), consisting of 15 x 120 s exposures.The images were processed using the WINTER data reduction pipeline implemented with mirar (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565). We detect a source at the optical counterpart location (Lipunov et al., GCN 43004; Lanava et al., GCN 43005; Lipunov et al., GCN 43006; de Ugarte Postigo et al., GCN 43008; Malesani et al., GCN 43009; O’Neill et al., GCN 43010; Mandarakas et al., GCN 43011; Pankov et al., GCN 43012; Bochenek et al., GCN 43015; Klinger et al., GCN 43016; Patil et al., GCN 43019; Pérez-Fournon et al., GCN 43020; Bochenek et al., GCN 43024; Busmann et al., GCN 43026; Hagio et al., GCN 43029; Bochenek et al., GCN 43038), with magnitude J = 17.9 ± 0.1 mag (AB). WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research. View this GCN Circular online at https://gcn.nasa.gov/circulars/43044. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41123] GRB 251208D: Swift-XRT observations
by GCN Circulars 09 Dec '25

09 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43043 SUBJECT: GRB 251208D: Swift-XRT observations DATE: 25/12/09 02:01:30 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P.A. Evans (U. Leicester), J.A. Kennea (PSU), E. Ambrosi (INAF-IASFPA) , A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), R. Brivio (INAF-OAB), D.N. Burrows (PSU), S. Campana (INAF-OAB), M. Capalbi (INAF-OAR), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), M. Ferro (INAF-OAB), A. Melandri (INAF-OAR), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Perri (SSDC & INAF-OAR), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.A. Williams (PSU) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the SVOM/ECLAIRs-detected source sb25120806 (GCN 43032), collecting 2.4 ks of Photon Counting (PC) mode data between T0+5.2 ks and T0+11 ks after the trigger. We have detected 2 sources. These have been automatically classified as follows: * 0 likely counterparts * 0 candidate counterparts * 1 uncatalogued X-ray source * 1 known X-ray source Uncatalogued X-ray sources -------------------------- Source 2 (SWIFT J223038.6-003107): ================================== RA (J2000.0): 337.6610 = 22 30 38.64 Dec (J2000.0): -0.5186 = -00 31 07.0 Error: 5.8 (arcsec, radius, 90% confidence). Detect flag: GOOD Distance: 10.7 arcmin from the SVOM/ECLAIRs position. Mean rate: (4.6 [+2.2, -1.7])e-3 ct s^-1 Mean flux: (4.6 [+2.2, -1.7])e-13 erg cm^-2 s^-1 Peak rate: (4.6 [+2.2, -1.7])e-3 ct s^-1 Peak flux: (4.6 [+2.2, -1.7])e-13 erg cm^-2 s^-1 ECF: 1.02e-10 erg cm^-2 ct^-1 assuming NH=3.34e+21 cm^-2, gamma=0.47 determined from a spectral fit. RASS UL: 1.6e-01 ct s^-1 (converted to XRT; 0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. A SIMBAD object `SDSS J223038.66-003108.3' is 1.2" away. Known X-ray sources ------------------- Source 1 (SWIFT J222951.0-001338): ================================== RA (J2000.0): 337.4626 = 22 29 51.02 Dec (J2000.0): -0.2273 = -00 13 38.3 Error: 5.2 (arcsec, radius, 90% confidence). Detect flag: GOOD Distance: 10.8 arcmin from the SVOM/ECLAIRs position. Mean rate: (5.6 [+2.4, -1.9])e-3 ct s^-1 Mean flux: (2.41 [+1.05, -0.81])e-13 erg cm^-2 s^-1 Peak rate: (5.6 [+2.4, -1.9])e-3 ct s^-1 Peak flux: (2.41 [+1.05, -0.81])e-13 erg cm^-2 s^-1 This matches a catalogued X-ray source 4XMM J222950.9-001339 in the XMM-NEWTON/XMMSSC catalogue. Details: Separation: 2.0" from the XRT source Cat Rate: 5.9e-02 +/- 8.2e-03 ct s^-1 Cat Flux: 6.0e-13 +/- 8.3e-14 erg cm^-2 s^-1 (0.3-10 keV) so the source is not above the catalogued flux. There is no evidence for fading. A SIMBAD object `TYC 5226-156-1' is 1" away. There is 1 2MASS object within the source's 3-sigma error radius. All fluxes are 0.3-10 keV, observed. For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2 and photon index (Gamma)=1.7 unless otherwise stated. The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/SVOM/SVOM_FIELD00056. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/43043. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41122] GRB 251208A: SVOM/GRM observation of a short burst
by GCN Circulars 09 Dec '25

09 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43042 SUBJECT: GRB 251208A: SVOM/GRM observation of a short burst DATE: 25/12/09 01:54:54 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: Frédéric Daigne (IAP) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by GRB 251208A (SVOM trigger reference: sb25120804) at 2025-12-08T09:25:58.000 (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #43027). 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 2.2 +0.9/-0.5 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251208A.png In addition, the position of this burst, as determined by Fermi/GBM (RA = 32.8, Dec = -66.7, position uncertainty = 3.9, GCN #43027), is located at about 61 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-1 to T0+2 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.20 +0.19/-0.18 and the cutoff energy, parameterized as Epeak, is 135 +51/-27 keV. The event fluence (10-1000 keV) in this time interval is (1.29 +0.19/-0.14)E-06 erg/cm^2. The 1s peak spectrum, measured from T0-0.6 to T0+0.4 s, if fitted by a power law function with an exponential high-energy cutoff, the power law index is -0.98 +0.17/-0.18 and the cutoff energy, parameterized as Epeak, is 139 +33/-21 keV. The flux (10-1000 keV) in this time interval is (7.79 +0.91/-0.72)E-07 erg/cm^2/s. The localization of GRB 251208A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251208A_amati.png The localization of GRB 251201A in the 'Yonetoku' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251208A_yonetoku.png In the absence of a measured redshift, the duration, soft spectrum, and position in the Amati diagram do not allow us to determine whether this burst is type I or type II. 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/43042. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41121] GRB 251208C: SVOM/GRM observation of a short burst
by GCN Circulars 09 Dec '25

09 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43041 SUBJECT: GRB 251208C: SVOM/GRM observation of a short burst DATE: 25/12/09 01:00:49 GMT FROM: Chenwei Wang at IHEP <cwwang(a)ihep.ac.cn> SVOM/GRM team: Chen-Wei Wang, Yue Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Frédéric Daigne (IAP) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by GRB 251208C (SVOM trigger reference: sb25120805) at 2025-12-08T12:52:32.600 (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #43030). 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 0.36 +0.06/-0.08 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251208C.png In addition, the position of this burst, as determined by Fermi/GBM (RA = 312.8 deg, Dec = -30.7 deg, Error=4.8 deg, GCN #43030), is located at about 84 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-0.12 to T0+0.04 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -0.54 +0.22/-0.19 and the cutoff energy, parameterized as Epeak, is 617 +241/-151 keV. The event fluence (10-1000 keV) in this time interval is (1.18 +0.09/-0.12)E-06 erg/cm^2. The localization of GRB 251208C in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251208C_amati.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: Chen-Wei Wang (IHEP) (cwwang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/43041. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41120] GRB 251129A: e-MERLIN C-band observations
by GCN Circulars 09 Dec '25

09 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43040 SUBJECT: GRB 251129A: e-MERLIN C-band observations DATE: 25/12/09 00:50:36 GMT FROM: Tao An at SHAO, CAS <antao(a)shao.ac.cn> Tao An (SHAO), Ailing Wang (IHEP), Emmanuel Bempong-Manful (UoM), Zigao Dai (USTC), and collaborators report on e-MERLIN observations of GRB 251129A. We observed GRB 251129A (GCN 42877, 42879, 42880, 42882, 42884, 42887, 42888, 42891, 42897, 42900, 42902, 42959, 42972, 42985) with the e-MERLIN array in the C band between 2025 December 3, 17:40 UT and December 5, 04:19 UT (project RR20009). Four antennas, Pickmere (Pi), Darnhall (Da), Knockin (Kn), and Cambridge (Cm), participated in the observation. Observing setup: - Frequency coverage: 4.82–5.33 GHz (C band), total bandwidth 512 MHz - Antennas: Pi, Da, Kn, Cm - Polarizations: Right and left circular - Spectral setup: 4 × 128 MHz spectral windows, 128 × 1 MHz channels per window (post-averaging) - Observation span: 2025-12-03 17:40 UT to 2025-12-05 04:19 UT The data were processed using the standard e-MERLIN pipeline followed by calibration and imaging in CASA. No significant radio emission was detected at the position of GRB 251129A. We place a 3σ upper limit of 0.066 mJy beam⁻¹ on the flux density. We encourage coordinated and continued radio follow-up to further constrain the flux density and probe potential variability at C band and complementary frequencies. We thank the e-MERLIN TAG and operations teams for their support. View this GCN Circular online at https://gcn.nasa.gov/circulars/43040. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41119] LAT GRB251208.43: Global MASTER-Net observations report
by GCN Circulars 09 Dec '25

09 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43039 SUBJECT: LAT GRB251208.43: Global MASTER-Net observations report DATE: 25/12/09 00:11:28 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the LAT GRB251208.43 (trigger No 786881842,15h 13m 55.20s , +29d 04m 12.0s, R=0.07) errorbox 23885 sec after notice time and 49564 sec after trigger time at 2025-12-09 00:03:21 UT, with upper limit up to 12.9 mag. The observations began at zenith distance = 82 deg. The sun altitude is -47.7 deg. The galactic latitude b = 58 deg., longitude l = 45 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3064689 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 49654 | 2025-12-09 00:03:21 | MASTER-Kislovodsk | (15h 12m 35.31s , +29d 07m 16.4s) | C | 180 | 12.9 | 49654 | 2025-12-09 00:03:21 | MASTER-Kislovodsk | (15h 12m 31.18s , +28d 44m 43.8s) | C | 180 | 12.6 | 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/43039. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41118] GRB 251205A: Liverpool Telescope further optical follow-up observations
by GCN Circulars 08 Dec '25

08 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43038 SUBJECT: GRB 251205A: Liverpool Telescope further optical follow-up observations DATE: 25/12/08 21:58:15 GMT FROM: A. Bochenek at Liverpool John Moores University <a.m.bochenek(a)2023.ljmu.ac.uk> A. Bochenek, D. A. Perley (LJMU), report: We observed the field of GRB 251205A (Lanava et al., GCN 43005) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 4x100s exposures in the SDSS i and r filters starting at 2025-12-08 05:21:03 UT, approximately 2.24 days after trigger. We report detections in the stacked images of both filters, at the position first reported by Lanava et al., GCN 43005: MJD (mid) T_mid-T_0 Filter Mag. (AB) 61017.22543 53.8 h i 21.02 ± 0.19 61017.23156 53.9 h r 21.14 ± 0.26 The photometry was obtained using nearby PanSTARRS secondary standards and was not corrected for extinction. The photometry is consistent with late-time optical measurements by Mandarakas et al., GCN 43011; Pérez-Fournon et al., GCN 43020; Bochenek & Perley, GCN 43024; and Hagio et al., GCN 43029. View this GCN Circular online at https://gcn.nasa.gov/circulars/43038. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41117] GRB 251208D: LCO optical upper limits
by GCN Circulars 08 Dec '25

08 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43037 SUBJECT: GRB 251208D: LCO optical upper limits DATE: 25/12/08 20:27:36 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> D. Turpin, A. Saccardi (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud), Z.-Y. Lin, F. Cangemi (APC), report on behalf of the SVOM mission team: We observed the field of the SVOM GRB 251208D (Lin et al., GCN 43032) with the LCO 1m telescope at South African Astronomical Observatory equipped with the Sinistro instrument. Our observation started on 2025-12-08 at 19:02:27 UT (about 2.18 hr after the trigger) and we obtained 3x200 s exposures in the SDSS r and 3x200 s exposures in the Pan-STARRS z filters. In the stacked image, we do not detect any new source within the ECLAIRs error circle. We measure the following upper limits calibrated against the PanSTARRS DR1 catalog, and not corrected for Galactic extinction: r > 21.6 AB (mid-time 2.27 hr after the trigger); z > 19.7 AB (mid-time 2.65 hr after the trigger). This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/43037. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41116] SVOM GRB251208.70: Global MASTER-Net observations report
by GCN Circulars 08 Dec '25

08 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43036 SUBJECT: SVOM GRB251208.70: Global MASTER-Net observations report DATE: 25/12/08 19:28:32 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the SVOM GRB251208.70 (trigger No 1765212621,22h 30m 08.33s , -00d 23m 30.5s, R=0.1962) errorbox 6047 sec after notice time and 7322 sec after trigger time at 2025-12-08 18:52:23 UT, with upper limit up to 13.3 mag. The observations began at zenith distance = 73 deg. The sun altitude is -56.3 deg. MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) was pointed to the SVOM GRB251208.70 errorbox 7366 sec after notice time and 8641 sec after trigger time at 2025-12-08 19:14:22 UT, with upper limit up to 19.0 mag. The observations began at zenith distance = 56 deg. The sun altitude is -17.9 deg. The galactic latitude b = -47 deg., longitude l = 66 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3064681 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 7382 | 2025-12-08 18:52:23 | MASTER-Kislovodsk | (22h 29m 37.06s , -00d 21m 55.6s) | C | 120 | 12.6 | 7382 | 2025-12-08 18:52:23 | MASTER-Kislovodsk | (22h 29m 37.94s , -00d 00m 13.8s) | C | 120 | 13.2 | 8671 | 2025-12-08 19:14:22 | MASTER-SAAO | (22h 28m 00.88s , -00d 37m 02.0s) | C | 60 | 18.9 | 8671 | 2025-12-08 19:14:22 | MASTER-SAAO | (22h 26m 18.28s , -00d 21m 13.1s) | C | 60 | 18.5 | 8764 | 2025-12-08 19:15:54 | MASTER-SAAO | (22h 27m 55.90s , -00d 37m 31.3s) | C | 60 | 19.0 | 8764 | 2025-12-08 19:15:54 | MASTER-SAAO | (22h 26m 13.40s , -00d 21m 40.9s) | C | 60 | 18.6 | 8867 | 2025-12-08 19:17:38 | MASTER-SAAO | (22h 26m 12.54s , -00d 20m 34.9s) | C | 60 | 18.5 | 8892 | 2025-12-08 19:18:03 | MASTER-Kislovodsk | (22h 29m 36.09s , -00d 22m 32.0s) | C | 60 | 12.2 | 8892 | 2025-12-08 19:18:03 | MASTER-Kislovodsk | (22h 29m 39.94s , -00d 01m 05.5s) | C | 60 | 13.2 | 8972 | 2025-12-08 19:19:22 | MASTER-Kislovodsk | (22h 29m 33.23s , -00d 02m 12.0s) | C | 60 | 13.3 | 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/43036. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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