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

[vsnet-grb-info 41068] GRB 251203A: AstroSat CZTI detection
by GCN Circulars 04 Dec '25

04 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42991 SUBJECT: GRB 251203A: AstroSat CZTI detection DATE: 25/12/04 18:21:20 GMT FROM: Anuraag Arya at IIT Bombay <aryaanuraag910(a)gmail.com> Harsha K. H. (IUCAA), S. Salunke (IUCAA), M. Tembhurnikar (IUCAA), A. Arya (IITB), A. Goyal (IITB), U. Pathak (IITB), G. Waratkar (Caltech/IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long GRB 251203A which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 42968), and Konus-IPN (via IPN Notices). The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2025-12-03 08:19:00.50 UTC. The measured peak count rate associated with the burst is 148 (+38, -16) counts/s above the background in the combined data of three quadrants (out of four), with a total of 775 (+165, -169) counts. The local mean background count rate was 225 (+3, -3) counts/s. Using cumulative rates, we measure a T90 of 15 (+2, -3) s. The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2025-12-03 08:18:47.01 UTC. The measured peak count rate associated with the burst is 150 (+70, -22) counts/s above the background in the combined data of all quadrants, with a total of 989 (+427, -457) counts. The local mean background count rate was 1321 (+7, -8) counts/s. We measure a T90 of 15 (+1, -7) s from the cumulative Veto light curve. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb View this GCN Circular online at https://gcn.nasa.gov/circulars/42991. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41067] EP251130a: JinShan near-infrared observations
by GCN Circulars 04 Dec '25

04 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42990 SUBJECT: EP251130a: JinShan near-infrared observations DATE: 25/12/04 16:38:15 GMT FROM: syfu(a)nao.cas.cn S.Y. Fu (HUST), L.B. He (NAOC), A.D. Zhu, L. Lei, H.Z. Wu, W.H. Lei (HUST), J. An, S.Q. Jiang, X. Liu, Z.P. Zhu, D. Xu (NAOC), J.Z. Liu (XAO) We continued monitoring the optical counterpart of EP251130a (Wu et al., GCN 42903) using the 100C telescope, equipped with the INS-BIue SWIR camera, of the JinShan project, located at Altay, Xinjiang, China. Observation started at 2025-12-01 16:29:07 UT, i.e., 1.22 days post-burst, and a series of J-band frames were obtained. The previously reported optical counterpart (Dornic et al., GCN 42904; He et al. GCN 42914; Gupta et al. GCN 42916; Zheng et al. GCN 42917; Dalen et al. GCN 42918; Moskvitin & Spiridonova, GCN 42919; Aryan et al. GCN 42921; Volnova et al. GCN 42922; Ma et al. GCN 42940; Corcoran et al. GCN 42951; Rodríguez et al. GCN 42963; Abidkhanov et al. GCN 42969) was detected in our stacked J-band frame with magnitude J = 19.19 +/- 0.12 (Vega) at a mid-time 1.32 days post-burst. The magnitude was calibrated with the nearby 2MASS catalog and without the Galactic extinction correction. We acknowledge the excellent support from T.Q. Chen and J.F. Zhang for enabling these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/42990. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41066] Fermi Gamma-ray Burst Monitor trigger 786496343/251203967 is not a GRB
by GCN Circulars 04 Dec '25

04 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42989 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 786496343/251203967 is not a GRB DATE: 25/12/04 16:12:47 GMT FROM: Suman Bala at USRA <sumanbala2210(a)gmail.com> S. Bala (USRA) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 786496343/251203967 at 23:12:18.62 UT on 03 December 2025, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to background fluctuation (accidental)." View this GCN Circular online at https://gcn.nasa.gov/circulars/42989. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41065] GRB 251203C: LCO optical afterglow confirmation
by GCN Circulars 04 Dec '25

04 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42988 SUBJECT: GRB 251203C: LCO optical afterglow confirmation DATE: 25/12/04 14:54:55 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> D. Turpin, A. Saccardi (CEA/Irfu), D. B. Malesani (DAWN/NBI and Radboud), J. T. Palmerio (CEA/Irfu), L. P. Xin, C. Wu (NAOC), B. Cordier (CEA/Irfu), M. Brunet, N. A. Webb (IRAP), report on behalf of the SVOM mission team: Following the report of an optical counterpart by SVOM/VT (Li et al., GCN 42987) of the SVOM GRB 251203C (Brunet et al., GCN 42976), we inspected again our stacked image from LCO (Turpin et al., GCN 42980). The VT candidate afterglow is detected in our r-band image. At a mean epoch of 37 min after trigger, we measure an SDSS r-band magnitude of r = 19.91 +/- 0.14 (AB, which is significantly brighter than the SVOM/VT magnitudes (despite the filter system difference) measured at a later epoch (> 3.3 hr after trigger). This further confirms that this source is the optical afterglow of GRB 251203C. The z-band upper limit reported by Turpin et al. (GCN 42980) is still confirmed. This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/42988. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41064] GRB 251203C: SVOM/VT optical counterpart
by GCN Circulars 04 Dec '25

04 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42987 SUBJECT: GRB 251203C: SVOM/VT optical counterpart DATE: 25/12/04 14:05:47 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> H.L. Li (NAOC), D. Turpin (CEA), Y.N. Ma, L.P. Xin, Y. L. Qiu, C. Wu, Z.H. Yao, 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), M. Brunet, N. A. Webb (IRAP) report on behalf of the SVOM/VT team. SVOM/VT performed ToO observation to the field of GRB 251203C triggered by SVOM (Brunet et al., GCN 42976). The observation started at 2025-12-03T21:46:05 UTC, i.e., 3.2 hours post trigger in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. An uncatalogued source was detected within the ECLAIRs's error box (Brunet et al., GCN 42976), compared to the Legacy survey catalog. The position is at R.A., Dec. = 51.701538, -7.382688 degrees, equivalent to: R.A. (J2000) = 03:26:48.36 Dec. (J2000) = -07:22:57.67 with an uncertainty of 0.5 arcsec. The measurements in AB magnitudes are given below: Mid_time Band Exposure Time Magnitude (AB) 3.3 hour VT_B 970 sec 22.1+/-0.1 mag 3.3 hour VT_R 970 sec 21.7+/-0.1 mag 9.7 hour VT_B 4430 sec 23.0+/-0.3 mag 9.7 hour VT_R 4430 sec 22.4+/-0.2 mag Our photometry was not corrected for Galactic extinction. As this source has significantly faded during our observations, we suggest it is the optical afterglow of GRB 251203C. 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/42987. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41063] GRB 251203C: EP-FXT follow-up observation
by GCN Circulars 04 Dec '25

04 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42986 SUBJECT: GRB 251203C: EP-FXT follow-up observation DATE: 25/12/04 14:02:16 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> H.Z. Wu (HUST), Y. Wu (NJU), H. Y. Ren, Tian-Yu Liu, G. J. Yang, W. D. Zhang (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of the SVOM/ECLAIRs-detected burst GRB 251203C (SVOM/sb25120305, Brunet et al., GCN #42976) at 2025-12-03 20:12:47 (UTC), about 52 minutes after the SVOM/ECLAIRs trigger, with an exposure time of 4569 s. Four uncataloged sources are detected within the ECLAIRs error circle. Preliminary analysis on these sources is automatically conducted, and the details are listed as follows. EPF_J032718.1-071802 RA (J2000): 51.8268 Dec (J2000): -7.3024 Flux: 9.24 x 10^-14 erg/s/cm2 (observed, 0.5-10 keV) Flux_err: 2.78 x 10^-14 erg/s/cm2 (1 sigma) EPF_J032703.9-072334 RA (J2000): 51.7662 Dec (J2000): -7.3929 Flux: 1.07 x 10^-13 erg/s/cm2 (observed, 0.5-10 keV) Flux_err: 3.23 x 10^-14 erg/s/cm2 (1 sigma) EPF_J032718.1-071802 RA (J2000): 51.8255 Dec (J2000): -7.3005 Flux: 5.85 x 10^-14 erg/s/cm2 (observed, 0.5-10 keV) Flux_err: 2.12 x 10^-14 erg/s/cm2 (1 sigma) EPF_J032658.4-072128 RA (J2000): 51.7434 Dec (J2000): -7.3577 Flux: 1.12 x 10^-13 erg/s/cm2 (observed, 0.5-10 keV) Flux_err: 2.77x 10^-14 erg/s/cm2 (1 sigma) 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/42986. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41062] GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
by GCN Circulars 04 Dec '25

04 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42985 SUBJECT: GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis DATE: 25/12/04 09:35:09 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> H. Yang, M. Brunet, O. Godet, J.-L. Atteia (IRAP), W. J. Xie (NAOC), W. J. Tan (IHEP), D. F. Kong (GXU) Using the event-by-event data downloaded through the X-band ground stations, we report further analysis of ECLAIRs observations of GRB 251129A/EP251129a (SVOM burst-id sb25112901, GCN 42877) detected at T0 = 2025-11-29T02:32:05 UT, which was also detected by EP/WXT (GCN 42884). The burst that triggered ECLAIRs shows a featureless light curve, and is detected from T0-41 s to T0+3200 s in the 4-120 keV energy band, indicating that it may be an ultra-long GRB or a very bright afterglow or a combination of both. The peculiar multi-wavelength temporal behavior of this event makes it a burst of great interest. ECLAIRs observations of GRB 251129A/EP251129a were interrupted by a slew and by a pass through the SAA, which divides the data into three time intervals for the time-averaged spectra analysis. The time-averaged spectrum from T0-41 s to T0+77 s (before the slew) in the 4-120 keV is well fitted by a power-law model with a photon index of 1.7+/-0.1 and a corresponding 4-120 keV flux of (1.5+/-0.2)e-8 erg/cm^2/s. The spectrum from T0+190 s to T0+585 s (after the slew and before the SAA transit) in the 4-120 keV is well fitted by a power-law model with a photon index of 2.1+/-0.1, with a 4-120 keV flux of (3.9+0.5-0.4)e-9 erg/cm^2/s. The spectrum from T0+1600 s to T0+3200 s (after the SAA transit) in the 4-120 keV is well fitted by a power-law model with a photon index of 2.0+/-0.1, with a 4-120 keV flux of (1.5+0.1-0.3)e-9 erg/cm^2/s. Overall, the ECLAIRs spectral analysis shows that GRB 251129A/EP251129a is decreasing in fluxes, and shows no significant spectral evolution from T0+190 s to T0+3200 s. The photon index measured from T0+190 s to T0+3200 s is consistent with that measured from EP/FXT at T0+2643 s (GCN 42902). The long-lasting emission seen by ECLAIRs matches the X-ray emission of the uncatalogued source seen by SVOM/MXT (GCN 42877). All the quoted errors are at the 68% confidence level. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. The SVOM/ECLAIRs point of contact for this burst is: Hui Yang (IRAP) (hui.yang(a)irap.omp.eu) View this GCN Circular online at https://gcn.nasa.gov/circulars/42985. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41061] GRB 251129B: GECAM-B observation of a burst
by GCN Circulars 04 Dec '25

04 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42984 SUBJECT: GRB 251129B: GECAM-B observation of a burst DATE: 25/12/04 08:30:50 GMT FROM: xueyuan zao <zaoxueyuan(a)gmail.com> Xue-Yuan Zao, Yue Wang, Zheng-Hang Yu, Chen-Wei Wang, Chao Zheng, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-B was triggered in-flight and on-ground by a short/hard burst GRB 251129B at 2025-11-29T09:51:34.250 UTC (denoted as T0). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of a single pulse main emission with a duration (T90) of 0.25 +0.10/-0.15 s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecambgrb251129B.png Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS). View this GCN Circular online at https://gcn.nasa.gov/circulars/42984. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41060] GRB 251203B: Swift-XRT observations
by GCN Circulars 03 Dec '25

03 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42983 SUBJECT: GRB 251203B: Swift-XRT observations DATE: 25/12/03 22:35:55 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> S. Lanava (PSU), 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 sb25120304, collecting 972 s of Photon Counting (PC) mode data between T0+4.6 ks and T0+5.7 ks after the trigger. A candidate counterpart has been found. The details of this source are: Source 1 (SWIFT J011326.9+000111): ================================== RA (J2000.0): 18.3625 = 01 13 27.00 Dec (J2000.0): +0.0198 = +00 01 11.3 Error: 3.5 (arcsec, radius, 90% confidence). Detect flag: GOOD Distance: 5.9 arcmin from the SVOM/ECLAIRs position. Mean rate: 1.785 +/- 0.088 ct s^-1 Mean flux: (5.76 +/- 0.28)e-11 erg cm^-2 s^-1 Peak rate: 2.72 +/- 0.62 ct s^-1 Peak flux: (8.8 +/- 2.0)e-11 erg cm^-2 s^-1 ECF: 3.23e-11 erg cm^-2 ct^-1 assuming NH=1.00e+21 cm^-2, gamma=2.03 determined from a spectral fit. This matches a catalogued X-ray source 4XMM J011326.8+000107 in the XMM-NEWTON/XMMSSC catalogue. Details: Separation: 3.3" from the XRT source Cat Rate: 2.7e-01 +/- 1.0e-02 ct s^-1 Cat Flux: 2.4e-12 +/- 8.9e-14 erg cm^-2 s^-1 (0.3-10 keV) so the source is 4.3-sigma above the catalogued flux. The source may be fading, at the 0.3-sigma level. A SIMBAD object `Gaia DR3 2534635509050352256' is 4.2" away. There is 1 2MASS object within the source's 3-sigma error radius. As pointed out by Malesani et al. (GCNs 42979), Brunet et al. (GCN 42981) and Perez-Garcia at al. (GCN 42982) this suggest that the transient is due to flaring activity from this star. We have detected a total of 4 sources. These have been automatically classified as follows: * 0 likely counterparts * 1 candidate counterpart * 3 uncatalogued X-ray sources * 0 known X-ray sources Uncatalogued X-ray sources -------------------------- Source 2 (SWIFT J011329.9-000900): ================================== RA (J2000.0): 18.3746 = 01 13 29.90 Dec (J2000.0): -0.1502 = -00 09 00.7 Error: 7.9 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 10.3 arcmin from the SVOM/ECLAIRs position. Mean rate: (6.9 [+4.4, -3.1])e-3 ct s^-1 Mean flux: (3.0 [+1.9, -1.3])e-13 erg cm^-2 s^-1 Peak rate: (6.9 [+4.4, -3.1])e-3 ct s^-1 Peak flux: (3.0 [+1.9, -1.3])e-13 erg cm^-2 s^-1 XMM UL: 1.8e-14 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. Source 3 (SWIFT J011422.6+000036): ================================== RA (J2000.0): 18.5945 = 01 14 22.68 Dec (J2000.0): +0.0102 = +00 00 36.7 Error: 8.3 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 8.1 arcmin from the SVOM/ECLAIRs position. Mean rate: (6.2 [+4.0, -2.8])e-3 ct s^-1 Mean flux: (2.6 [+1.7, -1.2])e-13 erg cm^-2 s^-1 Peak rate: (6.2 [+4.0, -2.8])e-3 ct s^-1 Peak flux: (2.6 [+1.7, -1.2])e-13 erg cm^-2 s^-1 XMM UL: 1.1e-14 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. Source 4 (SWIFT J011327.9-000300): ================================== RA (J2000.0): 18.3663 = 01 13 27.91 Dec (J2000.0): -0.0501 = -00 03 00.4 Error: 9.4 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 6.4 arcmin from the SVOM/ECLAIRs position. Mean rate: (-1.0 +/- -1.0)e0 ct s^-1 Mean flux: (-4.3 +/- -4.3)e-11 erg cm^-2 s^-1 Peak rate: (4.0 [+3.3, -2.3])e-3 ct s^-1 Peak flux: (1.7 [+1.4, -1.0])e-13 erg cm^-2 s^-1 XMM UL: 3.6e-14 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. 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_FIELD00054. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42983. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41059] GRB 251203B: confirmation of a stellar flare by BOOTES-2
by GCN Circulars 03 Dec '25

03 Dec '25

TITLE: GCN CIRCULAR NUMBER: 42982 SUBJECT: GRB 251203B: confirmation of a stellar flare by BOOTES-2 DATE: 25/12/03 21:59:40 GMT FROM: I. Perez-Garcia at Institute of Astrophysics of Andalusia <ipg(a)iaa.es> I. Perez-Garcia, M.D. Caballero-Garcia, E. J. Fernandez-Garcia, R. Sanchez-Ramirez, S.-Y. Wu, S. Guziy, and A. J. Castro-Tirado (IAA-CSIC, Granada), Y.-D. Hu (GXU), C. Perez del Pulgar and A. Reina (Univ. of Malaga), M. Gritsevich (Univ. of Helsinki), R. Fernandez-Munoz (IHSM/UMA-CSIC), D. R. Xiong (Yunnan Observatories of CAS), and M. Jelinek (ASU-CAS, Ondrejov Obs.), on behalf of a larger collaboration, report: Following the detection of trigger sb25120304 by SVOM (Brunet et al. GCN 42973), the 0.6m robotic telescope BOOTES-2/TELMA at IHSM La Mayora/UMA-CSIC (Malaga, Spain) responded to the alert on Dec 3, 18:16 UT (i.e. 7 min after detection). A serie of 3 sec images in clear fiter were taken. As reported by Palmerio et al. (GCN 42978) and Malesani et al. (GCN 42979) we measure the star Gaia DR3 2534635509050352256 to fade by ~1.8 mag over a ~20 min interval, consistent with a stellar flare and confirming its non-GRB origin, as stated in Brunet et al. (GCN 42981). We thank the staff at IHSM La Mayora/UMA-CSIC for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/42982. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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