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

[vsnet-grb-info 42850] EP260526a: EP-FXT follow-up observation
by GCN Circulars 28 May '26

28 May '26

TITLE: GCN CIRCULAR NUMBER: 44721 SUBJECT: EP260526a: EP-FXT follow-up observation DATE: 26/05/28 08:53:38 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> J. Yang (ZZU), B. T. Wang (YNAO, CAS), D. F. Hu (PMO, CAS), J. P. Feng, B. Zhang (USTC), D. Zhu, K. J. Zhang (YNU) and W. D. Zhang (NAO,CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of EP260526a (detected by EP-WXT, GCN 44712; and followed by LCO, GCN 44713) about 27 hours after the WXT detection, with an exposure time of 6 ks. The FXT telemetry data show that an uncatalogued source was detected within the WXT error circle at R.A. = 236.0897, DEC = -23.7507 (J2000) with an uncertainty of 10 arcsec (radius, 90% C.L. statistical and systematic). The FXT X-ray spectrum of this uncatalogued source can be fitted with an absorbed powerlaw with a hydrogen column density fixed at the Galactic value of 2.13 x 10^21 cm^-2 and a photon index of 1.8 (+1.5/-1.0). The derived unabsorbed 0.5-10 keV flux is approximately 5.2 (+5.2/-2.7) x 10^-14 erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. 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/44721. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42849] EP260527a: SVOM/VT optical observation
by GCN Circulars 28 May '26

28 May '26

TITLE: GCN CIRCULAR NUMBER: 44720 SUBJECT: EP260527a: SVOM/VT optical observation DATE: 26/05/28 07:13:15 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> H. L. Li, C. Wu, Y. L. Qiu, L. P. Xin, 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, L. Lan, J. S. Deng, J. Y. Wei (NAOC) and J. Palmerio (CEA/Irfu) report on behalf of the SVOM/VT team. SVOM/VT performed ToO observations to the field of EP260527a triggered by Einstein Probe (Yang et al., GCN 44718). The observation started at 2026-05-28T02:57:38 UTC, 20.63 hours post trigger in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously. The optical counterpart (Aguilar-Ruiz et al., GCN 44719) was detected by VT in both channels. The following measurements are in the AB magnitude without correction for Galactic extinction: Mid time | Band | Exposure Time | Brightness 21.76 h VT_B 29*50 s 22.32 +/- 0.22 mag 21.81 h VT_R 23*50 s 21.77 +/- 0.19 mag 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/44720. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42848] EP260527a: COLIBRÍ optical detection
by GCN Circulars 28 May '26

28 May '26

TITLE: GCN CIRCULAR NUMBER: 44719 SUBJECT: EP260527a: COLIBRÍ optical detection DATE: 26/05/28 06:36:51 GMT FROM: Francesco Magnani at Aix-Marseille Université, CPPM/CNRS <francesco.magnani.work(a)gmail.com> Edilberto Aguilar-Ruiz (UNAM), Francesco Magnani (CPPM), Alan M. Watson (UNAM), Rosa L. Becerra (UNAM), Antonio de Ugarte Postigo (LAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), 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), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), and Benjamin Schneider (LAM) and report: We imaged the field of the EP260527a (J. Yang et al, GCN Circ. 44718) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-05-28 04:13 to 06:05 UTC (from 21.90 to 23.76 hours after the trigger) and obtained 18, 62, and 82 minutes of exposure in the g, r, and z 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 (in this case with a relatively high value of A_v = 1.1 mag, according to Schlafly et al. 2011). In the stacked images, we detect an uncatalogued source within the FXT uncertainty region at: RA (J2000) = 12:52:13.13 = 193.05473 degrees Dec (J2000) = +01:28:56.8 = 1.48244 degrees The preliminary magnitudes derived for that source is: g = 22.25 +/- 0.32, r = 22.19 +/- 0.17, z = 21.52 +/- 0.15. The detection in g suggests that it is not a high-redshift event. Further observations are ongoing. 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/44719. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42847] EP260527a: Einstein Probe detection of a fast X-ray transient
by GCN Circulars 28 May '26

28 May '26

TITLE: GCN CIRCULAR NUMBER: 44718 SUBJECT: EP260527a: Einstein Probe detection of a fast X-ray transient DATE: 26/05/28 03:21:10 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> J. Yang (ZZU), B. T. Wang (YNAO, CAS), D. F. Hu (PMO, CAS), J. P. Feng, B. Zhang (USTC), D. Zhu, K. J. Zhang (YNU) and W. D. Zhang (NAO,CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of a fast X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP260527a. The transient triggered EP-WXT (ID: 01709266119) at 2026-05-27T06:19:54 (UTC). The WXT position of the source is R.A. = 193.057 deg, DEC = 1.473 deg (J2000) with an uncertainty of 2.3 arcmin in radius (90% C.L. statistical and systematic). The preliminary analysis of the WXT data shows that the event started at 2026-05-27T06:16:18 (UTC) and lasted for about 200 seconds. The average WXT 0.5-4.0 keV spectrum can be fitted with an absorbed powerlaw model, with a fixed Galactic hydrogen column density of 1.57 x 10^20 cm^-2 and a photon index of 0.73(+0.44/-0.42). The unabsorbed 0.5-4.0 keV flux is 1.12(+0.33/-0.28) x 10^(-9) erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. This event did not trigger the Follow-up X-ray Telescope (FXT) autonomous follow-up. A follow-up observation with the FXT was performed about 20.5 hours after the WXT detection. Within the WXT error circle, an uncatalogued X-ray source was detected at R.A. = 193.0519 deg, DEC = 1.4832 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic). Further information will be updated when the telemetry data are received. 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/44718. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42846] The EP-WXT trigger 01709266172 is likely a flaring star
by GCN Circulars 28 May '26

28 May '26

TITLE: GCN CIRCULAR NUMBER: 44717 SUBJECT: The EP-WXT trigger 01709266172 is likely a flaring star DATE: 26/05/28 01:48:41 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R.-Z. Li (YNAO, CAS), D. Zhu, K.-J. Zhang (YNU), D.-F. Hu (PMO, CAS), M.-H. Zhang and Y. Liu (NAO, CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709266172 at the time of 2026-05-28T01:30:15, is likely a stellar flare associated with CD-33 8642 (High Proper Motion Star). The estimated flux of the flare is around 6 x 10^(-11) erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 6.5 x 10^(31) erg/s. 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/44717. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42845] The EP-WXT trigger 01709266147 is likely a flaring star
by GCN Circulars 28 May '26

28 May '26

TITLE: GCN CIRCULAR NUMBER: 44716 SUBJECT: The EP-WXT trigger 01709266147 is likely a flaring star DATE: 26/05/28 01:10:19 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R.-Z. Li (YNAO, CAS), D. Zhu, K.-J. Zhang (YNU), D.-F. Hu (PMO, CAS), M.-H. Zhang and Y. Liu (NAO, CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709266147 at the time of 2026-05-27T19:27:35, is likely a stellar flare associated with UCAC4 262-085424 (Young Stellar Object Candidate). The estimated flux of the flare is around 1.6 x 10^(-10) erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 3.9 x 10^(32) erg/s. 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/44716. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42844] Fermi trigger No 801580882: Global MASTER-Net observations report
by GCN Circulars 27 May '26

27 May '26

TITLE: GCN CIRCULAR NUMBER: 44715 SUBJECT: Fermi trigger No 801580882: Global MASTER-Net observations report DATE: 26/05/27 23:32:27 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB260527.56 (trigger No 801580882,04h 33m 31.92s , +25d 09m 00.0s, R=34.02) errorbox 32285 sec after notice time and 32319 sec after trigger time at 2026-05-27 22:19:57 UT, with upper limit up to 16.2 mag. The observations began at zenith distance = 79 deg. The sun altitude is -22.7 deg. MASTER-Tavrida robotic telescope located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB260527.56 errorbox 35876 sec after notice time and 35911 sec after trigger time at 2026-05-27 23:19:48 UT, with upper limit up to 14.4 mag. The observations began at zenith distance = 79 deg. The sun altitude is -20.1 deg. The galactic latitude b = -15 deg., longitude l = 174 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3342387 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 32350 | 2026-05-27 22:19:57 | MASTER-Kislovodsk | (02h 18m 21.64s , +48d 14m 30.3s) | C | 60 | 15.8 | 32548 | 2026-05-27 22:23:15 | MASTER-Kislovodsk | (02h 42m 51.73s , +50d 08m 35.3s) | C | 60 | 15.6 | 32648 | 2026-05-27 22:24:55 | MASTER-Kislovodsk | (02h 13m 21.39s , +46d 22m 36.9s) | C | 60 | 14.4 | 32856 | 2026-05-27 22:28:22 | MASTER-Kislovodsk | (02h 36m 35.69s , +48d 14m 11.1s) | C | 60 | 15.2 | 33178 | 2026-05-27 22:33:44 | MASTER-Kislovodsk | (02h 08m 47.36s , +44d 29m 27.5s) | C | 60 | 14.9 | 33494 | 2026-05-27 22:39:01 | MASTER-Kislovodsk | (02h 30m 48.83s , +46d 22m 41.4s) | C | 60 | 15.0 | 33817 | 2026-05-27 22:44:24 | MASTER-Kislovodsk | (02h 04m 47.76s , +42d 34m 55.9s) | C | 60 | 14.8 | 34202 | 2026-05-27 22:50:49 | MASTER-Kislovodsk | (02h 25m 46.25s , +44d 28m 34.2s) | C | 60 | 13.9 | 34313 | 2026-05-27 22:52:40 | MASTER-Kislovodsk | (02h 54m 41.12s , +48d 16m 38.9s) | C | 60 | 14.7 | 34422 | 2026-05-27 22:54:29 | MASTER-Kislovodsk | (02h 00m 58.83s , +40d 43m 24.4s) | C | 60 | 14.8 | 34722 | 2026-05-27 22:59:28 | MASTER-Kislovodsk | (02h 48m 29.20s , +46d 22m 19.9s) | C | 60 | 14.9 | 34843 | 2026-05-27 23:01:30 | MASTER-Kislovodsk | (02h 21m 06.32s , +42d 36m 37.1s) | C | 60 | 15.3 | 34940 | 2026-05-27 23:03:07 | MASTER-Kislovodsk | (01h 57m 39.49s , +38d 48m 17.6s) | C | 60 | 15.3 | 35715 | 2026-05-27 23:16:02 | MASTER-Kislovodsk | (02h 16m 57.39s , +40d 42m 08.4s) | C | 60 | 16.2 | 35941 | 2026-05-27 23:19:48 | MASTER-Tavrida | (03h 04m 17.85s , +49d 18m 29.0s) | C | 60 | 14.4 | 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/44715. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42843] GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
by GCN Circulars 27 May '26

27 May '26

TITLE: GCN CIRCULAR NUMBER: 44714 SUBJECT: GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search DATE: 26/05/27 17:11:22 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> M. Brunet (IRAP), S. Schanne, N. Dagoneau (CEA), report on behalf of the SVOM/ECLAIRs team The SVOM/ECLAIRs telescope detected a transient source, labelled GRB 260524A, starting at 2026-05-24T12:01:52 UTC (trigger time T0) through an on-ground search with the event-by-event data downloaded through the X-band ground station. The burst was detected within several energy ranges and timescales. The best detection is obtained by the Image Trigger with a signal-to-noise ratio of 9.5 within 4-20 keV over a time window of 20.48 seconds starting at T0-20.48s. The burst shows a single peak lightcurve in the event-by-event data. The burst duration is estimated to be about 36 s in the 4-20 keV energy band through imaging. We note that just before the trigger, the source was masked by the Earth, so that part of the GRB emission may not have been observed by ECLAIRs. The localization of the source is RA, Dec = 115.192, -55.287 degrees: RA (J2000) = 07h 40m 46.1s Dec (J2000) = −55d17m13.2s with a 90% C.L. radius of 10.1 arcmin (including systematic error of 6 arcmin added in quadrature). We note that no bright catalogued X-ray sources are found in the error box. The time-averaged spectrum from T0-32 s to T0+4 s in the energy range 5-50 keV is best fitted by a blackbody model with kT = 2.63 +/-0.27. With this model, the 4-120 keV fluence is (3.3 +0.2/-0.7) e-7 erg/cm² and the 4-120 keV photon flux is 0.63 +0.04/-0.13 ph/cm²/s. We note that a powerlaw model does not give a good fit. Other models such as broken power-law and power-law with an exponential cutoff do not yield constrained parameters. The spectral parameters indicate that this GRB is very soft and should probably be classified as an X-Ray Flash. 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: Marius Brunet (IRAP) (marius.brunet at utoulouse.fr) View this GCN Circular online at https://gcn.nasa.gov/circulars/44714. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42842] EP260526a: LCO optical upper limits
by GCN Circulars 27 May '26

27 May '26

TITLE: GCN CIRCULAR NUMBER: 44713 SUBJECT: EP260526a: LCO optical upper limits DATE: 26/05/27 12:19:35 GMT FROM: Agnes van Hoof at Radboud University <agnes.vanhoof(a)ru.nl> A. P. C. van Hoof (Radboud), R. A. J. Eyles-Ferris (Leicester), J. Quirola-Vasquez (Radboud), P. G. Jonker (Radboud), D. B. Malesani (DAWN/NBI and Radboud), J. A. Chacón (PUC), F. E. Bauer (SSI and UTA), report on behalf of a larger collaboration: We observed the field of the X-ray transient EP260526a (Yang et al, GCN 44712) using LCO 1m telescopes located at the Cerro Tololo observatory equipped with SINISTRO instruments. A series of 5x300 s exposures were taken using the SDSS-r filter and 3x300 s using the SDSS-z filter, starting on 2026-05-27 at 08:07:52 UT (i.e., ~1.4 days after the first X-ray detection). No new source is detected within the EP/WXT uncertainty region compared with the Legacy and Pan-STARRS surveys. From the stacked images, we obtain the following 3-sigma upper limits, consistent with those reported by Becerra et al. (GCN 44710):  r > 22.5 z > 20.6 These upper limits are in AB magnitudes, calibrated using nearby stars from the Pan-STARRS catalogue, and are not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44713. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42841] EP260526a: Einstein Probe detection of a fast X-ray transient
by GCN Circulars 27 May '26

27 May '26

TITLE: GCN CIRCULAR NUMBER: 44712 SUBJECT: EP260526a: Einstein Probe detection of a fast X-ray transient DATE: 26/05/27 07:03:44 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> J. Yang (ZZU), B. T. Wang (YNAO, CAS), D. F. Hu (PMO, CAS), J. P. Feng, B. Zhang (USTC), D. Zhu, K. J. Zhang (YNU) and W. D. Zhang (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of a fast X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP260526a. The transient did not trigger the onboard unit, a GCN notice (ID: 06800001478) was sent manually. The WXT position of the source is R.A. = 236.063 deg, DEC = -23.771 deg (J2000) with an uncertainty of 2.4 arcmin in radius (90% C.L. statistical and systematic). The preliminary analysis of the WXT data shows that the event started at 2026-05-26T09:43:34 (UTC) and lasted for about 140 seconds. The average WXT 0.5-4.0 keV spectrum can be fitted with an absorbed powerlaw model, with a fixed Galactic hydrogen column density of 2.13 x 10^21 cm^-2 and a photon index of 1.98 (+0.78/-0.70). The unabsorbed 0.5-4.0 keV flux is 8.2 (+2.8/-2.2) x 10^(-10) erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. Further FXT observations are scheduled. Additional information will be updated when the telemetry data are received. 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/44712. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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