January 2026 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 41559] EP260119a: SAO RAS optical observations
by GCN Circulars 20 Jan '26

20 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43463 SUBJECT: EP260119a: SAO RAS optical observations DATE: 26/01/20 00:19:23 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. S. Moskvitin and O. I. Spiridonova (SAO RAS) report on behalf of GRB follow-up team. We observed the field of the EP260119a (Jiang et al., GCN 43447; Cheng et al., GCN 43449) with the Zeiss-1000 1m telescope of the SAO RAS equipped with the CCD photometer. We obtained 8 x 300 sec in Ic band on on Jan. 19, 21:33:52--22:18:23 UT (t_mid - T0 = 0.90439 days). The OT (Fortin et al., GCN 43450; GCN 43455; Eyles-Ferris et al., GCN 43452) is clearly detected in our stacked frame with the brightness of I = 20.8 +/- 0.1 (I_lim = 22.0). This preliminary photometry is based on several nearby SDSS stars (I-magnitudes obtained with Lupton 2005 transformation) and is not corrected for the Galactic extinction. Magnitudes is in Vega system. View this GCN Circular online at https://gcn.nasa.gov/circulars/43463. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41558] SVOM GRB260119.92: Global MASTER-Net observations report
by GCN Circulars 19 Jan '26

19 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43462 SUBJECT: SVOM GRB260119.92: Global MASTER-Net observations report DATE: 26/01/19 23:42:41 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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the SVOM GRB260119.92 (trigger No 1768860656,11h 26m 01.66s , +61d 23m 16.8s, R=1) errorbox 391 sec after notice time and 436 sec after trigger time at 2026-01-19 22:18:12 UT, with upper limit up to 19.6 mag. The observations began at zenith distance = 19 deg. The sun altitude is -24.8 deg. The galactic latitude b = 53 deg., longitude l = 139 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3108068 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 467 | 2026-01-19 22:18:12 | MASTER-Tunka | (11h 18m 02.89s , +62d 30m 22.3s) | C | 60 | 19.6 | 467 | 2026-01-19 22:18:12 | MASTER-Tunka | (11h 16m 31.83s , +62d 39m 17.8s) | C | 60 | 19.3 | 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/43462. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41557] SVOM GRB260119.92: Global MASTER-Net observations report
by GCN Circulars 19 Jan '26

19 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43461 SUBJECT: SVOM GRB260119.92: Global MASTER-Net observations report DATE: 26/01/19 23:42:34 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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the SVOM GRB260119.92 (trigger No 1768860172,08h 23m 32.59s , +57d 17m 44.5s, R=1) errorbox 708 sec after notice time and 838 sec after trigger time at 2026-01-19 22:16:50 UT, with upper limit up to 19.4 mag. The observations began at zenith distance = 40 deg. The sun altitude is -25.0 deg. The galactic latitude b = 35 deg., longitude l = 160 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3108061 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 869 | 2026-01-19 22:16:50 | MASTER-Tunka | (08h 21m 45.46s , +57d 40m 30.1s) | C | 60 | 19.4 | 869 | 2026-01-19 22:16:50 | MASTER-Tunka | (08h 20m 28.54s , +57d 48m 24.1s) | C | 60 | 18.9 | 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/43461. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41556] SVOM GRB260119.90: Global MASTER-Net observations report
by GCN Circulars 19 Jan '26

19 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43460 SUBJECT: SVOM GRB260119.90: Global MASTER-Net observations report DATE: 26/01/19 22:14:22 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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the SVOM GRB260119.90 (trigger No 1768858916,00h 49m 46.66s , +45d 01m 16.7s, R=1) errorbox 211 sec after notice time and 323 sec after trigger time at 2026-01-19 21:47:19 UT, with upper limit up to 16.8 mag. The observations began at zenith distance = 84 deg. The sun altitude is -29.7 deg. The galactic latitude b = -18 deg., longitude l = 123 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3108046 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 334 | 2026-01-19 21:47:19 | MASTER-Tunka | (00h 49m 43.25s , +45d 13m 31.9s) | C | 20 | 16.7 | 355 | 2026-01-19 21:47:43 | MASTER-Tunka | (00h 49m 43.34s , +45d 13m 38.0s) | C | 15 | 16.7 | 371 | 2026-01-19 21:48:01 | MASTER-Tunka | (00h 49m 43.26s , +45d 13m 33.8s) | C | 10 | 16.6 | 384 | 2026-01-19 21:48:15 | MASTER-Tunka | (00h 49m 43.25s , +45d 13m 27.7s) | C | 10 | 16.5 | 398 | 2026-01-19 21:48:29 | MASTER-Tunka | (00h 49m 43.20s , +45d 13m 41.8s) | C | 10 | 16.6 | 398 | 2026-01-19 21:48:29 | MASTER-Tunka | (00h 49m 19.71s , +45d 19m 14.6s) | C | 10 | 16.4 | 412 | 2026-01-19 21:48:42 | MASTER-Tunka | (00h 49m 43.11s , +45d 13m 46.0s) | C | 10 | 16.6 | 425 | 2026-01-19 21:48:56 | MASTER-Tunka | (00h 49m 43.18s , +45d 13m 28.1s) | C | 10 | 16.6 | 439 | 2026-01-19 21:49:09 | MASTER-Tunka | (00h 49m 43.10s , +45d 13m 28.8s) | C | 10 | 16.7 | 452 | 2026-01-19 21:49:23 | MASTER-Tunka | (00h 49m 43.14s , +45d 13m 39.3s) | C | 10 | 16.7 | 466 | 2026-01-19 21:49:37 | MASTER-Tunka | (00h 49m 43.13s , +45d 13m 33.2s) | C | 10 | 16.6 | 483 | 2026-01-19 21:49:50 | MASTER-Tunka | (00h 49m 43.02s , +45d 13m 44.9s) | C | 15 | 16.8 | 501 | 2026-01-19 21:50:09 | MASTER-Tunka | (00h 49m 43.11s , +45d 13m 32.9s) | C | 15 | 16.8 | 520 | 2026-01-19 21:50:27 | MASTER-Tunka | (00h 49m 43.08s , +45d 13m 32.3s) | C | 15 | 16.8 | 538 | 2026-01-19 21:50:46 | MASTER-Tunka | (00h 49m 43.08s , +45d 13m 33.7s) | C | 15 | 16.8 | 554 | 2026-01-19 21:51:05 | MASTER-Tunka | (00h 49m 43.03s , +45d 13m 55.1s) | C | 10 | 16.7 | 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/43460. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41555] EP 260116a: COLIBRÍ detection of a fading optical source
by GCN Circulars 19 Jan '26

19 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43459 SUBJECT: EP 260116a: COLIBRÍ detection of a fading optical source DATE: 26/01/19 21:20:37 GMT FROM: Alan Watson at UNAM <alan(a)astro.unam.mx> Nathaniel R. Butler (ASU), Noémie Globus (UNAM), Alan M. Watson (UNAM), Jean-Luc Atteia (IRAP), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Asuka Kuwata (UNAM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), and Antonio de Ugarte Postigo (LAM) report: We observed the field of EP 260116a (Wang et al., GCN Circ. 43424) obtained with the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope on the nights of 2026 January 17, 18, and 19 UTC at median times of 30.8, 52.4, and 78.7 hours after the trigger and obtained 80, 96, and 128 minutes, respectively, of simultaneous exposure in the r and z filters. The data were reduced, coadded, calibrated, and analyzed with the COLIBRÍ ASU pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. We reported preliminary results from the first night in Magnani et al. (GCN Circ. 43436). In contrast to our initial analysis, a refined reprocessing and the subsequent follow up observations have revealed a fading optical source located within the EP/WXT error region (Wang et al., GCN Circ. 43424) at the coordinates RA = 07:35:14.14, Dec = +06:20:14.3 (J2000). At the last epoch, we measure preliminary magnitudes of r = 23.22 +/- 0.06, z = 22.81 +/- 0.14. Including these observations together with the two earlier epochs, we model the temporal evolution of the source flux with a power-law decay. We find Flux_r = t^(−0.33 +/- 0.12) and Flux_z = t^(-0.53 +/- 0.23). The source therefore exhibits a slow but consistent decay, which is statistically significant and supports its interpretation as the fading optical counterpart of EP 260116a. No existing source is visible at this position in the PS1 images. Further observations are planned. We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams. COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico. View this GCN Circular online at https://gcn.nasa.gov/circulars/43459. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41554] GRB 251208D: SVOM/ECLAIRs refined analysis
by GCN Circulars 19 Jan '26

19 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43458 SUBJECT: GRB 251208D: SVOM/ECLAIRs refined analysis DATE: 26/01/19 20:59:19 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> H. Yang, O. Godet (IRAP), F. Daigne (IAP), Z.-Y. Lin, F. Cangemi (APC) Using the event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of the possible faint burst GRB 251208D (SVOM burst-id sb25120806, GCN 43032) detected at T0 = 2025-12-08T16:51:43 UT. The burst that triggered ECLAIRs shows a featureless light curve, and is detected from T0-82 s to T0 in the 8-120 keV energy band. The time-averaged spectrum from T0-82 s to T0 in the 8-120 keV is well fitted by a power-law model with a photon index of 1.8+/-0.4 and a corresponding 4-120 keV fluence of (1.1+/-0.3)e-6 erg/cm^2. 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/43458. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41553] GRB 251208D: SVOM/ECLAIRs refined analysis
by GCN Circulars 19 Jan '26

19 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43457 SUBJECT: GRB 251208D: SVOM/ECLAIRs refined analysis DATE: 26/01/19 20:58:08 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> H. Yang, O. Godet (IRAP), F. Daigne (IAP), Z.-Y. Lin, F. Cangemi (APC) Using the event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of the possible faint burst GRB 251208D (SVOM burst-id sb25120806, GCN 43032) detected at T0 = 2025-12-08T16:51:43 UT. The burst that triggered ECLAIRs shows a featureless light curve, and is detected from T0-82 s to T0 in the 8-120 keV energy band. The time-averaged spectrum from T0-82 s to T0 in the 8-120 keV is well fitted by a power-law model with a photon index of 1.8+/-0.4 and a corresponding 4-120 keV fluence of (1.1+/-0.3)e-6 erg/cm^2. 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/43457. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41552] GRB 251208D: SVOM/ECLAIRs refined analysis
by GCN Circulars 19 Jan '26

19 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43457 SUBJECT: GRB 251208D: SVOM/ECLAIRs refined analysis DATE: 26/01/19 20:58:08 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> H. Yang, O. Godet (IRAP), F. Daigne (IAP), Z.-Y. Lin, F. Cangemi (APC) Using the event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of the possible faint burst GRB 251208D (SVOM burst-id sb25120806, GCN 43032) detected at T0 = 2025-12-08T16:51:43 UT. The burst that triggered ECLAIRs shows a featureless light curve, and is detected from T0-82 s to T0 in the 8-120 keV energy band. The time-averaged spectrum from T0-82 s to T0 in the 8-120 keV is well fitted by a power-law model with a photon index of 1.8+/-0.4 and a corresponding 4-120 keV fluence of (1.1+/-0.3)e-6 erg/cm^2. 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/43457. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41551] GRB 260117A: Swift-XRT afterglow detection
by GCN Circulars 19 Jan '26

19 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43456 SUBJECT: GRB 260117A: Swift-XRT afterglow detection DATE: 26/01/19 20:06:20 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> C. Salvaggio (INAF-OAB), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), D.N. Burrows (PSU), S. Lanava (PSU), S. Dichiara (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has conducted further observations of the field of the SVOM/ECLAIRs-detected burst GRB 260117A. The observations now extend from T0+12.5 ks to T0+153.1 ks and have a total exposure time of 5.7 ks. Of the sources previously reported, "Source 1" is fading with >3-sigma significance, and is therefore likely the GRB afterglow. Using 1064 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 = 188.13864, +43.91274 which is equivalent to: RA (J2000): 12h 32m 33.27s Dec(J2000): +43d 54' 45.9" with an uncertainty of 4.9 arcsec (radius, 90% confidence). This position is 2.5 arcmin from the SVOM/ECLAIRs position, and 0.2 arcsec from the SVOM/VT optical candidate reported in GCN Circ. 43411. The source is fading with alpha >0.2. The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/00021898. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021898. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/43456. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41550] EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
by GCN Circulars 19 Jan '26

19 Jan '26

TITLE: GCN CIRCULAR NUMBER: 43455 SUBJECT: EP260119a: COLIBRÍ photometric redshift z ≈ 5.6 DATE: 26/01/19 18:02:49 GMT FROM: Alan Watson at UNAM <alan(a)astro.unam.mx> Francis Fortin (IRAP), Leonardo García García (UNAM), Camila Angulo (UNAM), Nikos Mandarakas (LAM), Alan M. Watson (UNAM), Jean-Grégoire Ducoin (CPPM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Asuka Kuwata (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), and Antonio de Ugarte Postigo (LAM) report: We imaged the field of EP260119a (Jiang et al., GCN Circ. 43447; Cheng et al., GCN CIrc. 43449) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-01-19 09:00 to 13:37 UTC (from 8.7 to 13.4 hours after the trigger) and obtained 105, 53, 97, and 32 minutes of exposure in the r, i, z, and y filters. The data were reduced and coadded with the COLIBRÍ ASU pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. Our longer time interval and multi-filter photometry allows us to estimate the decay index and the photometric redshift of the optical counterpart reported by ourselves in Fortin et al. (GCN Circ. 43450) and confirmed by Eyles-Ferris et al. (GCN Circ 43452). In the z band, we see a shallow decay with a temporal index of -0.44 +/- 0.19. The counterpart is detected in all four bands. After correcting for the Galactic foreground extinction corresponding to a reddening of E(B-V) = 0.011 mag (Schlafly & Finkbeiner 2011) and fitting a power-law model to the rizy-bands using a no dust extinction curve, we derive a photometric redshift of z = 5.62 with formal errors of +0.02-0.03 (1-sigma c.l.). We caution that our magnitudes are not strictly simultaneous, but nevertheless the break from z to i to r is much stronger than can be accounted for by this effect. We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams. COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico. View this GCN Circular online at https://gcn.nasa.gov/circulars/43455. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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