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

[vsnet-grb-info 43539] GRB 260808B: SVOM/VT optical candidate from VHF data
by GCN Circulars 08 Aug '26

08 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45317 SUBJECT: GRB 260808B: SVOM/VT optical candidate from VHF data DATE: 26/08/08 16:03:31 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> D. Turpin (CEA/Irfu), C. Wu (NAOC), A. Saccardi (CEA/Irfu), L. P. Xin (NAOC), M. Dinatolo (U. Milano), report on behalf of the SVOM/VT team: After the trigger by SVOM/ECLAIRs at 2026-08-08T14:20:58 UTC (T0), SVOM performed an automatic slew on the burst location (sb26080812, Bouchet et al., GCN 45316). SVOM/VT began observing the field in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. From a preliminary analysis of the source list and 1-bit subimage downloaded via VHF network, at least one credible candidate is identified, the details of which are presented below. VT_ID 40: The position of this candidate is R.A., Dec. 345.23359 8.47848 degrees, corresponding to: R.A. (J2000) = 23:00:56.06 Dec. (J2000) = +08:28:42.5 with an uncertainty of 0.5 arcsec. This candidate was detected in both VT_R and VT_B in the first sequence of images and no longer detected in the following ones. No minor planet objects were found at the position of the candidate and within a 1 arcmin radius. No catalogue source was found in the Legacy DR10 catalog. The candidate's magnitudes are: | date-obs (UTC) | mid-time（sec） | exposure | VT_B mag(AB) | VT_R mag(AB) | | -------------------- | ----------- | --------- | ------------- | ------------- | | 2026-08-08T14:25:16.000 | 408 | 6x50s | 21.72 ± 0.10 | 21.02 ± 0.08 | Magnitudes were not corrected for Galactic reddening. 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. SVOM/VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. The Burst Advocate (BA) on shift for this alert is Michela Maria Dinatolo: michela.dinatolo(a)unimi.it. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/45317. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43538] GRB 260808B: SVOM/VT optical afterglow confirmation
by GCN Circulars 08 Aug '26

08 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45320 SUBJECT: GRB 260808B: SVOM/VT optical afterglow confirmation DATE: 26/08/08 18:38:06 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> H. L. Li, C. Wu, L. P. Xin, Y. L. Qiu, Y. N. Ma, Z. H. Yao, J. R. Xu, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. S. Deng, J. Y. Wei (NAOC), J. T. Palmerio (CEA/Irfu), M. Dinatolo (U. Milano) report on behalf of the SVOM/VT team. SVOM/VT performed observations with automatic slew for GRB 260808B triggered by SVOM/ECLAIRs (sb26080812, Bouchet et al., GCN 45316) and detected by SVOM/MXT (Bouchet et al., GCN 45316). The observation started at 2026-08-08T14:24:26 UTC, i.e., 208 seconds post trigger in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously. The optical candidate (Damien et al., GCN 45318) was detected in both channels. The position is at R.A., Dec. = 345.233538, 8.478528 degrees, equivalent to: R.A. (J2000) = 23:00:56.05 Dec. (J2000) = +8:28:42.70 with an uncertainty of 0.5 arcsec. The following measurements are in the AB magnitude and are not corrected for Galactic extinction: Mid time | Band | Exposure Time | Brightness 233 s VT_B 50 s 20.9 +/- 0.2 mag 233 s VT_R 50 s 20.3 +/- 0.1 mag 1.51 h VT_B 16*50 s 22.8 +/- 0.2 mag 1.51 h VT_R 16*50 s 22.0 +/- 0.2 mag The source faded rapidly with a temporal decay slope of -1.9 in both channels during our early observations taken within 400 seconds post trigger. 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/45320. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43537] GRB 260808C: Fermi GBM Final Real-time Localization
by GCN Circulars 08 Aug '26

08 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45319 SUBJECT: GRB 260808C: Fermi GBM Final Real-time Localization DATE: 26/08/08 16:34:47 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 SHORT GRB At 16:24:14 UT on 8 Aug 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260808C (trigger 807899059.114984 / 260808683). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 214.2, Dec = 34.1 (J2000 degrees, equivalent to J2000 14h 16m, 34d 06'), with a statistical uncertainty of 13.2 degrees. The angle from the Fermi LAT boresight is 36.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260808683/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260808683/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260808683/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45319. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43536] GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 )
by GCN Circulars 08 Aug '26

08 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45318 SUBJECT: GRB 260808B: SVOM/VT optical candidate from VHF data ( localization correction for GCN 45317 ) DATE: 26/08/08 16:29:07 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> D. Turpin (CEA/Irfu), C. Wu (NAOC), A. Saccardi (CEA/Irfu), L. P. Xin (NAOC), M. Dinatolo (U. Milano), report on behalf of the SVOM/VT team: After the trigger by SVOM/ECLAIRs at 2026-08-08T14:20:58 UTC (T0), SVOM performed an automatic slew on the burst location (sb26080812, Bouchet et al., GCN 45316). SVOM/VT began observing the field in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. From a preliminary analysis of the source list and 1-bit subimage downloaded via VHF network, at least one credible candidate is identified, the details of which are presented below. VT_ID 40: The position of this candidate is R.A., Dec. 345.23359 8.47848 degrees, corresponding to: R.A. (J2000) = 23:00:56.06 Dec. (J2000) = +08:28:42.5 with an uncertainty of 0.5 arcsec. This candidate was detected in both VT_R and VT_B in the first sequence of images and no longer detected in the following ones. No minor planet objects were found at the position of the candidate and within a 1 arcmin radius. No catalogue source was found in the Legacy DR10 catalog. The candidate's magnitudes are: | date-obs (UTC) | mid-time（sec） | exposure | VT_B mag(AB) | VT_R mag(AB) | | -------------------- | ----------- | --------- | ------------- | ------------- | | 2026-08-08T14:25:16.000 | 408 | 6x50s | 21.72 ± 0.10 | 21.02 ± 0.08 | Magnitudes were not corrected for Galactic reddening. 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. SVOM/VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. The Burst Advocate (BA) on shift for this alert is Michela Maria Dinatolo: michela.dinatolo(a)unimi.it. Please contact the BA by email if you require additional information View this GCN Circular online at https://gcn.nasa.gov/circulars/45318. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43535] GRB 260808B: SVOM/VT optical candidate from VHF data
by GCN Circulars 08 Aug '26

08 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45317 SUBJECT: GRB 260808B: SVOM/VT optical candidate from VHF data DATE: 26/08/08 16:03:31 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> D. Turpin (CEA/Irfu), C. Wu (NAOC), A. Saccardi (CEA/Irfu), L. P. Xin (NAOC), M. Dinatolo (U. Milano), report on behalf of the SVOM/VT team: After the trigger by SVOM/ECLAIRs at 2026-08-08T14:20:58 UTC (T0), SVOM performed an automatic slew on the burst location (sb26080812, Bouchet et al., GCN 45316). SVOM/VT began observing the field in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. From a preliminary analysis of the source list and 1-bit subimage downloaded via VHF network, at least one credible candidate is identified, the details of which are presented below. VT_ID 40: The position of this candidate is R.A., Dec. 349.76751, 13.62404 degrees, corresponding to: R.A. (J2000) = 23:19:04.2 Dec. (J2000) = +13:37:26.5 with an uncertainty of 0.5 arcsec. This candidate was detected in both VT_R and VT_B in the first sequence of images and no longer detected in the following ones. No minor planet objects were found at the position of the candidate and within a 1 arcmin radius. No catalogue source was found in the Legacy DR10 catalog. The candidate's magnitudes are: | date-obs (UTC) | mid-time（sec） | exposure | VT_B mag(AB) | VT_R mag(AB) | | -------------------- | ----------- | --------- | ------------- | ------------- | | 2026-08-08T14:25:16.000 | 408 | 6x50s | 21.72 ± 0.10 | 21.02 ± 0.08 | Magnitudes were not corrected for Galactic reddening. 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. SVOM/VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. The Burst Advocate (BA) on shift for this alert is Michela Maria Dinatolo: michela.dinatolo(a)unimi.it. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/45317. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43534] GRB 260808B: SVOM detection of a faint burst
by GCN Circulars 08 Aug '26

08 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45316 SUBJECT: GRB 260808B: SVOM detection of a faint burst DATE: 26/08/08 15:12:17 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Laurent Bouchet (IRAP), Sebastien Guillot (IRAP), Michela Dinatolo (U. Milano), Diego Götz (CEA) report on behalf of the SVOM mission team: At 2026-08-08T14:20:58 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260808# (SVOM burst-id sb26080812). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was only detected by the Image Trigger (IMT), which produced a sequence of 5 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 7.52 in the [5-20] keV energy band over a time window of 40.96 seconds starting at 2026-08-08T14:20:18. The localization of the best alert is R.A., Dec. 345.2202, 8.4310 degrees (J2000) with a 90% confidence level (C.L.) radius of 10.44 arcmin (including systematic error of 2 arcmin added in quadrature). SVOM slewed to the burst. SVOM/MXT began observing the field at 2026-08-08T14:23:30 UTC, 152 seconds after T0. Using onboard processed data we found an uncatalogued X-ray source located at R.A., Dec. 345.239, 8.467 degrees: R.A. (J2000) = 23h00m57.38s Dec. (J2000) = 8d28m00.34s with a 90% C.L. radius of 48 arcseconds. This location is 2.42 arcminutes from the ECLAIRs onboard position. This position may be improved as more data is received. VT began observing the field after the slew. The analysis of the data will be published in a future circular. 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. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE. The Burst Advocate (BA) on shift for this alert is Michela Maria Dinatolo: michela.dinatolo(a)unimi.it. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/45316. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43533] GRB 260808A: BALROG localization (Fermi Trigger 807850307 / GRB 260808119)
by GCN Circulars 08 Aug '26

08 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45315 SUBJECT: GRB 260808A: BALROG localization (Fermi Trigger 807850307 / GRB 260808119) DATE: 26/08/08 06:09:23 GMT FROM: Jochen Greiner at MPE <jcgrog(a)mpe.mpg.de> T. Preis (University of Innsbruck) & J. Greiner (MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 807850307 at 02:51:42 on 08 Aug. 2026 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position is: RA(2000.0) = 344.1 deg Decl.(2000.0) = 11.9 deg The 1 sigma statistical error radius is 2.9 deg. We estimate an additional systematic error of 1 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB260808119/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB260808119/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB260808119/json View this GCN Circular online at https://gcn.nasa.gov/circulars/45315. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43532] Fermi GRB 260808A: Global MASTER-Net observations report
by GCN Circulars 08 Aug '26

08 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45314 SUBJECT: Fermi GRB 260808A: Global MASTER-Net observations report DATE: 26/08/08 04:46:20 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), M. Segura, 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-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260808A ( Fermi GBM team, GCN 45313) errorbox 99 sec after notice time and 136 sec after trigger time at 2026-08-08 02:53:58 UT, with upper limit up to 19.2 mag. The observations began at zenith distance = 68 deg. The sun altitude is -61.1 deg. The galactic latitude b = -39 deg., longitude l = 84 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3463356 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 152 | 2026-08-08 02:53:58 | MASTER-OAFA | (22h 48m 26.72s , +15d 27m 39.0s) | C | 30 | 17.9 | 188 | 2026-08-08 02:54:35 | MASTER-OAFA | (22h 48m 26.71s , +15d 27m 41.6s) | C | 30 | 18.1 | 229 | 2026-08-08 02:55:11 | MASTER-OAFA | (22h 48m 26.79s , +15d 27m 43.8s) | C | 40 | 18.1 | 281 | 2026-08-08 02:55:58 | MASTER-OAFA | (22h 48m 26.78s , +15d 27m 46.4s) | C | 50 | 18.4 | 342 | 2026-08-08 02:56:53 | MASTER-OAFA | (22h 48m 26.83s , +15d 27m 49.2s) | C | 60 | 18.5 | 641 | 2026-08-08 03:01:23 | MASTER-OAFA | (22h 46m 41.95s , +14d 00m 48.5s) | C | 120 | 19.1 | 777 | 2026-08-08 03:03:29 | MASTER-OAFA | (22h 46m 41.99s , +14d 00m 54.5s) | C | 140 | 19.2 | 938 | 2026-08-08 03:05:55 | MASTER-OAFA | (22h 46m 41.94s , +14d 01m 00.1s) | C | 170 | 19.3 | 1060 | 2026-08-08 03:08:52 | MASTER-OAFA | (22h 46m 41.89s , +14d 01m 04.3s) | C | 60 | 18.8 | 1126 | 2026-08-08 03:09:58 | MASTER-OAFA | (22h 46m 41.85s , +14d 01m 06.4s) | C | 60 | 18.9 | 1191 | 2026-08-08 03:11:03 | MASTER-OAFA | (22h 46m 41.82s , +14d 01m 09.3s) | 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/45314. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43531] GRB 260808A: Fermi GBM Final Real-time Localization
by GCN Circulars 08 Aug '26

08 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45313 SUBJECT: GRB 260808A: Fermi GBM Final Real-time Localization DATE: 26/08/08 03:02:15 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 02:51:42 UT on 8 Aug 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260808A (trigger 807850307.310674 / 260808119). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 341.8, Dec = 14.1 (J2000 degrees, equivalent to J2000 22h 47m, 14d 05'), with a statistical uncertainty of 2.2 degrees. The angle from the Fermi LAT boresight is 72.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260808119/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260808119/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260808119/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45313. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43530] EP260806a: ZTF serendipitous detection of ZTF26abmjjnm / AT 2026yeh
by GCN Circulars 07 Aug '26

07 Aug '26

TITLE: GCN CIRCULAR NUMBER: 45312 SUBJECT: EP260806a: ZTF serendipitous detection of ZTF26abmjjnm / AT 2026yeh DATE: 26/08/07 20:52:13 GMT FROM: akashjanaki98(a)gmail.com Akash Anumarlapudi (UNC CH), Robert Stein (UMD), Tomas Ahumada (NOIRLab), Aleksandra Bochenek (LJMU), Mansi Kasliwal, Lin Yan (Caltech), Michael W. Coughlin, Michael C. Davis (UMN), D. Y. Li, C.C.Jin, W. Yuan (NAO, CAS) report, on behalf of the ZTF collaboration. We report the serendipitous detection of ZTF26abmjjnm/AT 2026yeh by the Zwicky Transient Facility (Bellm et al. 2019, Graham et al. 2019). ZTF26abmjjnm is the optical counterpart to the X-ray transient EP260806a (GCN #45299), previously detected by GCNs #45300, #45302, #45303, #45304, #45306. It was first observed by ZTF at T0+12 hrs, resulting in detections in g,r bands. With g = 18.69 +/- 0.09 AB and r = 18.93 +/- 0.09 AB the source appears blue. Previous observations, roughly 4 days prior, resulted in non-detection at the location of ZTF26abmjjnm with g, r > 19.9 AB. Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Award #2407588 and a partnership including Caltech, USA; Caltech/IPAC, USA; University of Maryland, USA; University of California, Berkeley, USA; University of Wisconsin at Milwaukee, USA; Cornell University, USA; Drexel University, USA; University of North Carolina at Chapel Hill, USA; Institute of Science and Technology, Austria; National Central University, Taiwan; Operations are conducted by Caltech's Optical Observatory (COO) and Caltech/IPAC. View this GCN Circular online at https://gcn.nasa.gov/circulars/45312. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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