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[vsnet-grb-info 43180] EP260616a/GRB260616B: COLIBRÍ optical upper limit
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44965 SUBJECT: EP260616a/GRB260616B: COLIBRÍ optical upper limit DATE: 26/06/17 14:44:26 GMT FROM: nikos.mandarakas(a)lam.fr Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), and Alan M. Watson (UNAM) report: We imaged the field of the EP 260616a (Li et al., GCN Circ. 44956), which is consistent in time and location with GRB 260616B (Malacaria et al., GCN Circ. 44953), using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-06-17 05:56:39 to 07:16:28 UTC (from 22.86 to 24.20 hours after the trigger) and obtained 48 minutes of simultaneous exposure in the r and z filters. The data were reduced, coadded and analysed with the ASU COLIBRÍ 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. In the stacked image, we do not detect any new source at the WXT source position (Li et al., GCN Circ. 44956) down to the following 5-sigma limit: r > 22.76 mag z > 22.20 mag We thank the staff of the Observatorio Astronómico Nacional at Sierra de San Pedro Mártir, as well as the technical and engineering teams at CEA, CPPM, IRAP, LAM, OHP, OSU Pytheas, and UNAM. 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/44965. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43179] GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44963 SUBJECT: GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening DATE: 26/06/17 09:33:10 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS), V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931), and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in Rc band on June 14, 15 and 16. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al., GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958; Dimple et al., GCN 44959) is detected in our stacked images with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3 2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8 2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve. View this GCN Circular online at https://gcn.nasa.gov/circulars/44963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43178] GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44963 SUBJECT: GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening DATE: 26/06/17 09:33:10 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS), V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931), and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in Rc band on June 14, 15 and 16. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al., GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958; Dimple et al., GCN 44959) is detected in our stacked images with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3 2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8 2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve. View this GCN Circular online at https://gcn.nasa.gov/circulars/44963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43177] GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44963 SUBJECT: GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening DATE: 26/06/17 09:33:10 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS), V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931), and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in Rc band on June 14, 15 and 16. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al., GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958; Dimple et al., GCN 44959) is detected in our stacked images with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3 2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8 2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve. View this GCN Circular online at https://gcn.nasa.gov/circulars/44963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43176] GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44963 SUBJECT: GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening DATE: 26/06/17 09:33:10 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS), V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931), and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in Rc band on June 14, 15 and 16. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al., GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958; Dimple et al., GCN 44959) is detected in our stacked images with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3 2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8 2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve. View this GCN Circular online at https://gcn.nasa.gov/circulars/44963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43175] GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44963 SUBJECT: GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening DATE: 26/06/17 09:33:10 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS), V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931), and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in Rc band on June 14, 15 and 16. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al., GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958; Dimple et al., GCN 44959) is detected in our stacked images with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3 2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8 2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve. View this GCN Circular online at https://gcn.nasa.gov/circulars/44963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43174] GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44963 SUBJECT: GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening DATE: 26/06/17 09:33:10 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS), V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931), and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in Rc band on June 14, 15 and 16. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al., GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958; Dimple et al., GCN 44959) is detected in our stacked images with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3 2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8 2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve. View this GCN Circular online at https://gcn.nasa.gov/circulars/44963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43173] GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44963 SUBJECT: GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening DATE: 26/06/17 09:33:10 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS), V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931), and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in Rc band on June 14, 15 and 16. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al., GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958; Dimple et al., GCN 44959) is detected in our stacked images with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3 2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8 2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve. View this GCN Circular online at https://gcn.nasa.gov/circulars/44963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43172] GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44963 SUBJECT: GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening DATE: 26/06/17 09:33:10 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS), V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931), and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in Rc band on June 14, 15 and 16. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al., GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958; Dimple et al., GCN 44959) is detected in our stacked images with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3 2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8 2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve. View this GCN Circular online at https://gcn.nasa.gov/circulars/44963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43171] GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
by GCN Circulars 17 Jun '26

17 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44963 SUBJECT: GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening DATE: 26/06/17 09:33:10 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Maslennikova (SAO RAS), V. Goranskij (SAI MSU, SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901; Godwin and Meegan; GCN 44931), and also detected by SVOM (Yu et al., GCN 44944), with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in Rc band on June 14, 15 and 16. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929; Akl et al., GCN 44930; Bochenek and Perley, GCN 44932; Pankov et al., GCN 44946; Gillanders et al., GCN 44955; Angulo et al., GCN 44958; Dimple et al., GCN 44959) is detected in our stacked images with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-14 23:15:23 4.56847 15*180 Rc 21.14 0.12 22.3 2026-06-15 23:42:44 5.57617 8*180 Rc 20.98 0.17 21.8 2026-06-16 20:30:40 6.44388 3*600 Rc 21.06 0.18 21.9 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. Although we cannot directly confirm that the afterglow brightness has increased, we can observe a plateau in the afterglow light curve. View this GCN Circular online at https://gcn.nasa.gov/circulars/44963. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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