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

[vsnet-grb-info 40174] GRB 251005A: Swift detection of a burst
by GCN Circulars 05 Oct '25

05 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42113 SUBJECT: GRB 251005A: Swift detection of a burst DATE: 25/10/05 16:23:27 GMT FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk> K. L. Page (U Leicester), S. Dichiara (PSU), R. Gupta (NASA GSFC), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL) and M. J. Moss (GSFC) report on behalf of the Neil Gehrels Swift Observatory Team: At 16:06:53 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 251005A (trigger=1401726). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 75.673, +16.882 which is RA(J2000) = 05h 02m 42s Dec(J2000) = +16d 52' 54" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a double-peaked structure with a duration of about 2 sec. The peak count rate was ~4,500 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 16:08:52.2 UT, 118.3 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source with an enhanced position: RA, Dec 75.68331, 16.88007 which is equivalent to: RA(J2000) = 05h 02m 44.00s Dec(J2000) = +16d 52' 48.3" with an uncertainty of 2.1 arcseconds (radius, 90% containment). This location is 36 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (3.19 x 10^21 cm^-2, Willingale et al. 2013), with an excess column of 5 (+3.76/-3.16) x 10^21 cm^-2 (90% confidence). UVOT took a finding chart exposure of 150 seconds with the White filter starting 122 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.461. Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) View this GCN Circular online at https://gcn.nasa.gov/circulars/42113. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40173] EP251003a: Einstein Probe detection of an X-ray transient
by GCN Circulars 05 Oct '25

05 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42107 SUBJECT: EP251003a: Einstein Probe detection of an X-ray transient DATE: 25/10/05 03:22:32 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Q. C. Liu (THU), Y. Q. Zhao (USTC), C. Zhou (HUST), H. W. Pan (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP251003a. The WXT position of the source is R.A. = 56.934 deg, DEC = -10.929 deg (J2000) with an uncertainty of 2.549 arcmin in radius (90% C.L. statistical and systematic). The transient was first detected by WXT in an observation that started at 2025-10-03T18:11:50 (UTC). The 0.5-4 keV spectrum can be fitted with an absorbed powerlaw model with hydrogen column density of 0.4(+3.2, -0.4)x10^21 cm^-2 and a photon index of 0.9(+1.1, -0.5). The average unabsorbed 0.5-4 keV flux is 3.8(+1.4, -1.1) x 10^-11 erg/s/cm^2. A follow-up observation with the Follow-up X-ray Telescope (FXT) was performed. An uncatalogued X-ray source was detected at R.A. = 56.9218 deg, DEC = -10.9321 deg (J2000) with an uncertainty of 10 arcsec in radius (90% C.L. statistical and systematic). The 0.5-10 keV spectrum can be fitted with an absorbed powerlaw model with hydrogen column density of 0.0 (+1.7, -0.0)x10^21 cm^-2 and a photon index of 1.7(+0.6, -0.2). The average unabsorbed 0.5-10 keV flux is 8.3(+1.6, -1.9) x 10^-13 erg/s/cm^2. All the uncertainties of the parameters are 90% C.L. statistical. Further follow-up observations are encouraged. 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/42107. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40172] GRB 251005B: Fermi GBM Final Real-time Localization
by GCN Circulars 05 Oct '25

05 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42112 SUBJECT: GRB 251005B: Fermi GBM Final Real-time Localization DATE: 25/10/05 14:37:49 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 14:27:19 UT on 5 Oct 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251005B (trigger 781367244.128264 / 251005602). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 298.6, Dec = -8.9 (J2000 degrees, equivalent to J2000 19h 54m, -8d 54'), with a statistical uncertainty of 6.5 degrees. The angle from the Fermi LAT boresight is 104.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251005602/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251005602/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251005602/… View this GCN Circular online at https://gcn.nasa.gov/circulars/42112. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40171] GRB 251002A: NIR observations with WINTER
by GCN Circulars 05 Oct '25

05 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42105 SUBJECT: GRB 251002A: NIR observations with WINTER DATE: 25/10/04 04:03:05 GMT FROM: Geoffrey Mo at Caltech / Carnegie Observatories <gmo(a)mit.edu> Geoffrey Mo (Caltech/Carnegie), Tomas Ahumada (Caltech), Viraj Karambelkar (Columbia/CCA), Benjamin Schneider (LAM), Robert Stein (UMD), Danielle Frostig (CfA), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report: We observed the field of GRB 251002A (Saccardi et al., GCN 42060; Sun et al., GCN 42075; Kenya et al., GCN 42084; Smith et al., GCN 42093) 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 2025-10-03T03:49:03 UTC in the J band (~7.6 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 do not detect a source at the optical counterpart location (Palmerio et al., GCN 42061; Turpin et al., GCN 42062; Jelinek et al., GCN 42063; Juliá-Maroto et al., GCN 42064; Moskvitin et al., GCN 42065; Perez-Garcia et al., GCN 42066; Senik et al., GCN 42067; Saccardi et al., GCN 42076; Mandarakas et al., GCN 42077; Cao et al., GCN 42078; Schneider et al., GCN 42080; Pankov et al., GCN 42081; Leonini et al., GCN 42082; Odeh et al., GCN 42087; Wortley et al., GCN 42091; Shilling et al., GCN 42099; Calapai et al., GCN 42101). We obtain the following 5-sigma upper limit: J ~ 19.2 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/42105. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40170] GRB 251003A: Swift/UVOT Upper Limits
by GCN Circulars 03 Oct '25

03 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42100 SUBJECT: GRB 251003A: Swift/UVOT Upper Limits DATE: 25/10/03 18:33:33 GMT FROM: s.shilling(a)lancaster.ac.uk S. P. R. Shilling (Lancaster U.), M. De Pasquale (Univ. Messina) and A. P. Beardmore (U. Leicester) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251003A 79 s after the BAT trigger (Beardmore et al., GCN Circ. 42070). No optical afterglow consistent with the enhanced XRT position (Evans et al., GCN Circ. 42088) or those reported by other instruments (Aceituno et al., GCN Circ. 42072; Moreno Méndez et al., GCN Circ. 42073; Strausbaugh et al., GCN Circ. 42074; Worssam et al., GCN Circ. 42094), is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 79 229 147 >20.70 u 291 474 180 >19.78 v 33828 34558 711 >20.01 b 43530 43837 298 >20.30 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.408 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/42100. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40169] GRB 251002A: Swift/UVOT detection
by GCN Circulars 03 Oct '25

03 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42099 SUBJECT: GRB 251002A: Swift/UVOT detection DATE: 25/10/03 18:26:26 GMT FROM: s.shilling(a)lancaster.ac.uk S.P.R. Shilling (Lancaster U.) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251002A in the U band for a total of 1.5 ks, starting 3.6 ks after the SVOM/ECLAIRs trigger (Saccardi et al., GCN Circ. 42060). A source is detected in the U band at a position that is consistent with other detections by other instruments in the optical (Palmerio et al., GCN 42061; Turpin et al., GCN 42062; Jelinek et al., GCN 42063; Julia-Maroto et al., GCN 42064; Moskvitin et al., GCN 42065; Perez-Garcia et al., GCN 42606; Senik et al., GCN 42067; Saccardi et al., GCN 42076; Mandarakas et al., GCN 42077; Cao et al., GCN 42078; Schneider et al., GCN 42080; Pankov et al., GCN 42081; Leonini et al., GCN 42082; Odeh et al., GCN 42087; Wortley et al., GCN 42091). Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the stacked U band images are: Filter T_start(s) T_stop(s) Exp(s) Mag U 3628 9263 1476 19.02 +/- 0.08 The magnitude reported here is not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/42099. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40168] GRB 251001A: AstroSat CZTI detection
by GCN Circulars 03 Oct '25

03 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42098 SUBJECT: GRB 251001A: AstroSat CZTI detection DATE: 25/10/03 18:19:12 GMT FROM: Anuraag Arya at IIT Bombay <aryaanuraag910(a)gmail.com> Harsha K. H. (IUCAA), M. Tembhurnikar (IUCAA), S. Salunke (IUCAA), A. Arya (IITB), A. Goyal (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 GRB 251001A which was also detected by Fermi/GBM (GCN Circ. 41993), Insight-HXMT (Wang et al., 42057). We detect only the second pulse as seen in the GBM lightcurve because the source is likely at a sky position where our effective area is low. The source was detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2025-10-01 02:40:59.96 UTC. The measured peak count rate associated with the burst is 372 (+65, -75) counts/s above the background in the combined data of all four quadrants, with a total of 333 (+172, -206) counts. The local mean background count rate was 1380 (+11, -11) counts/s. Due to the intrinsic 1 s binning of veto data, we cannot reliably estimate a T90 from it. 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/42098. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40167] GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay
by GCN Circulars 03 Oct '25

03 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42097 SUBJECT: GRB 251001B: COLIBRÍ further observations and evidence of a multi-wavelength shallow decay DATE: 25/10/03 17:59:09 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra(a)roma2.infn.it> Rosa L. Becerra (U Roma), Benjamin Schneider (LAM), Camila Angulo (UNAM), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc Atteia (IRAP), Dalya Akl (NYUAD), Sarah Antier (OCA), Nathaniel R. Butler (ASU) , Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), and Antonio de Ugarte Postigo (LAM): We reobserved the field of the GRB 251001B (Fermi GBM team, GCN Circ. 42038; Beardmore et al. GCN Circ. 42039) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2025-10-03 12:00 to 12:19 UTC (from 45.7 to 46.0 hours after the trigger) and obtained 16 minutes of simultaneous exposure in the r and z filters. The data were reduced and coadded with custom software and analysed with STDWeb/STDPipe (Karpov 2025). 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 detected the optical counterpart previously reported by Gompertz et al. (GCN Circ. 42040), An et al. (GCN Circ. 42041), Strausbaugh & Cucchiara (GCN Circ. 42043), O'Neill et al. (GCN Circ. 42046), de Ugarte Postigo et al. (GCN Circ. 42050), Ma et al. (GCN Circ. 42051), Sanchez-Ramirez et al. (GCN Circ. 42053), Schneider et al. (GCN Circ. 42054), and Breeveld et al. (GCN Circ. 42055) at preliminary magnitudes of: r = 22.28 +/- 0.14. z = 22.08 +/- 0.41 (with a 3-sigma detection limit of z = 21.85). By comparing the optical data reported by the aforementioned facilities and COLIBRÍ, we estimate a spectral index of approximately -0.5. This shallow decay is consistent with the temporal evolution observed in the X-ray band after 10ks from the trigger (https://www.swift.ac.uk/xrt_curves/01400467/) 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/42097. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40166] GRB 251003A: Swift-XRT refined Analysis
by GCN Circulars 03 Oct '25

03 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42096 SUBJECT: GRB 251003A: Swift-XRT refined Analysis DATE: 25/10/03 16:16:36 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-OAR), S. Lanava (PSU), S. Dichiara (PSU) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 6.8 ks of XRT data for GRB 251003A, from 59 s to 34.6 ks after the trigger. The data comprise 126 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The late-time light curve (from T0+4.6 ks) can be modelled with a power-law decay with a decay index of alpha=0.6 (+0.4, -0.3). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.67 (+0.11, -0.10). The best-fitting absorption column is 1.4 (+3.0, -1.4) x 10^22 cm^-2, at a redshift of 4.412, in addition to the Galactic value of 4.4 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.8 x 10^-11 (7.5 x 10^-11) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Galactic foreground: 4.4 x 10^21 cm^-2 Intrinsic column: 1.4 (+3.0, -1.4) x 10^22 cm^-2 at z=4.412 Photon index: 2.67 (+0.11, -0.10) If the light curve continues to decay with a power-law decay index of 0.6, the count rate at T+24 hours will be 8.2 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.3 x 10^-13 (6.1 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01400964. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42096. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40165] GRB 251003A: COLIBRÍ photometric redshift
by GCN Circulars 03 Oct '25

03 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42095 SUBJECT: GRB 251003A: COLIBRÍ photometric redshift DATE: 25/10/03 15:49:16 GMT FROM: Benjamin Schneider at MIT <bschn(a)mit.edu> Benjamin Schneider (LAM), Ny Avo Rakotondrainibe (LAM), Enrique Moreno Méndez (UNAM), Antonio de Ugarte Postigo (LAM), Camila Angulo (UNAM), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc Atteia (IRAP), Dalya Akl (NYUAD), Sarah Antier (OCA), Rosa L. Becerra (U Roma), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Margarita Pereyra (UNAM) and Fredd Sánchez Álvarez (UNAM): COLIBRÍ performed additional observations of the Fermi and Swift GRB 251003A (Fermi GBM team, GCN Circ. 42069; Beardmore et al., GCN Circ. 42070) starting from 2025-10-03 04:04:59 (2.1 hr after the trigger) and obtained images in the g, i, y filters. The photometry of the afterglow (Aceituno et al. GCN Circ. 42072; Moreno Méndez et al. GCN Circ. 42073; Strausbaugh et al. GCN Circ. 42074; Freeberg et al. GCN Circ. 42085; Worssam et al., GCN Circ. 42094) was performed using STDWeb/STDPipe (Karpov 2025), was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. After combining data obtained from Moreno Méndez et al., GCN Circ. 42073 and correcting for the Galactic foreground extinction corresponding to a reddening of E(B-V) = 0.36 mag (Schlafly & Finkbeiner 2011), we fit a power-law model to the grizy-bands using the SMC extinction curve and we derive a photometric redshift of z = 4.38+0.07-0.04 (1-sigma c.l., statistical errors only). Our result is consistent with the GTC/OSIRIS+ redshift of z = 4.41 (Sanchez-Ramirez et al., GCN Circular 42086). 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/42095. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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