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[vsnet-grb-info 43362] GRB 260708A: GRANDMA Optical Observations
by GCN Circulars 13 Jul '26

13 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45147 SUBJECT: GRB 260708A: GRANDMA Optical Observations DATE: 26/07/13 14:05:35 GMT FROM: Xinyue Sheng at Queens University Belfast <xysheng.astro(a)gmail.com> X. Sheng (QUB), D. Turpin (CEA/Irfu), O. Pyshna (Caltech), R. Strausbaugh (EIU), A. Iskandarova (ShAO), S. Rahimli (Sumgayit State Uni), V. Morozov (KU Leuven), S. Antier (IJCLAB), A. Simon (TShNU of Kyiv), L. Wyrzykowski (Uni. Warsaw/NCBJ), J. Hambsch (VVS, GEOS, BAV), M. Freeberg (KNC), R. Hellot (KNC), A. Klotz (IRAP), E. Jehin (ULiège), M. Ferrais (ULiège), Rui-Zhi (YNAO), J. Mao (YNAO) on behalf of on GRANDMA collaboration: We observed the field of the Fermi Long GRB 260708A (Fermi GBM team, GCN 45115; Fermi/LAT, Holzmann Airasca et al., GCN45117,; GECAM-B, Ren et al., GCN45126; Glowbug, Cheung et al., GCN 45130). The observations started at 14:30:42 UTC on the 9 of July 2026, 1.18 days post the Fermi Trigger. We detected the optical afterglow candidate, reported by MASTER (Shilova et al, GCN 45123), in several epochs, using the 60cm telescope at les Makes Observatory, the LCO 0.4m telescope at the SAA Observatory, the TRAPPIST-South telescope at la SIlla Observatory, and Kilonova Catcher. However, we observed after template substraction a softer decay than usual for the GRBs. A subset of the photometry corrected for Galactic extinction is reported in the public ACME service Skyportal/ICARE https://skyportal-icare.ijclab.in2p3.fr/source/GRB-260708A. To access, one simply needs to create an account using your ORCID id. The data were reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained with the Sloan filters were calibrated using the PanSTARRS DR1 catalog. Images obtained with the Johnson-Cousins filters were calibrated using the Gaia DR3 Synphot catalog. Our results are consistent across GRANDMA but not totally with LCO (GCN 45140). Further template taken at later time are needed. The observations are performed under the P7 campaign of GRANDMA to monitor SVOM alerts and LSST alerts from explosive fast transients filtered by BOOM/Babamul and FINK. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/) View this GCN Circular online at https://gcn.nasa.gov/circulars/45147. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43361] Fermi-LAT Gamma-ray Observations of IceCube-260712A
by GCN Circulars 13 Jul '26

13 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45146 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-260712A DATE: 26/07/13 11:13:23 GMT FROM: Leo Pfeiffer at University of Würzburg <pfeiffer.leo(a)gmail.com> L. Pfeiffer (Univ. of Wuerzburg), S. Buson (DESY, Univ. of Wuerzburg), S. Garrappa (Weizmann Institute of Science) and C. Bartolini (INFN Bari) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC260712A neutrino event (GCN 45141) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The IceCube event was detected on 26-07-12 at 11:06:48.98 UTC (T0) with J2000 position RA = 200.11 (+0.70, -0.66) deg, Decl. = 48.29 (+0.47, -0.44) deg 90% PSF containment (J2000). No cataloged gamma-ray sources are found within the 90% IC260712A localization error (FL16Y, The Fermi-LAT 16 Year Source List, The Fermi-LAT collaboration 2026, arXiv:2602.22148). We searched for the existence of intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (> 100 MeV) within the IC260712A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC260712A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 1.0e-10 ph cm^-2 s^-1 for ~18-years (2008-08-04 / T0), <4.9e-09 (<4.2e-08) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For this analysis, the Fermi-LAT contact person is L. Pfeiffer (leonard.pfeiffer at uni-wuerzburg.de). The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/45146. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43360] Fermi-LAT Gamma-ray Observations of IceCube-260708A
by GCN Circulars 13 Jul '26

13 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45145 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-260708A DATE: 26/07/13 11:10:59 GMT FROM: Leo Pfeiffer at University of Würzburg <pfeiffer.leo(a)gmail.com> L. Pfeiffer (Univ. of Wuerzburg), S. Buson (DESY, Univ. of Wuerzburg), S. Garrappa (Weizmann Institute of Science) and C. Bartolini (INFN Bari) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC260708A neutrino event (GCN 45120) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The IceCube event was detected on 2026-07-08 at 17:17:42.55 UTC (T0) with J2000 position RA = 292.81 (+0.48, -0.47) deg, Decl. = -15.17 (+0.44, -0.48) deg 90% PSF containment (J2000). No cataloged gamma-ray sources are found within the 90% IC260708A localization error (FL16Y, The Fermi-LAT 16 Year Source List, The Fermi-LAT collaboration 2026, arXiv:2602.22148). We searched for the existence of intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (> 100 MeV) within the IC260708A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC260708A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 8.0e-10 ph cm^-2 s^-1 for ~18-years (2008-08-04 / T0), <5.7e-08 (<1.4e-07) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. We test the presence of an additional point source at the position of the optical transient AT2026kuv, which is a candidate supernova discovered by GOTO on 2026-04-20 (GCN 45125). The transient is located within the error region of IC260708A at 3.9 arcmin from the neutrino best-fit direction. No significant gamma-ray emission was detected. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the AT2026kuv best-fit position, the >100 MeV flux upper limit (95% confidence) is < 5.8e-08 ph cm^-2 s^-1 for a 1-month integration time before T0. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For this analysis, the Fermi-LAT contact person is L. Pfeiffer (leonard.pfeiffer at uni-wuerzburg.de). The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/45145. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43359] GRB 260710A: Insight-HXMT/HE detection
by GCN Circulars 13 Jul '26

13 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45144 SUBJECT: GRB 260710A: Insight-HXMT/HE detection DATE: 26/07/13 08:27:04 GMT FROM: Xinghao Luo at IHEP <2952704891(a)qq.com> Xing-Hao Luo, Chen-Wei Wang, Chao Zheng, and Shao-Lin Xiong (IHEP) report on behalf of the Insight-HXMT team: At 2026-07-10T12:56:43.800 (T0), Insight-HXMT/HE detected the GRB 260710A, which is also detected by Fermi/GBM (Fermi GBM Team, GCN #45131). The Insight-HXMT/HE light curve mainly consists of a single pulse with a T90 of 1.2 +1.2/-0.4 s. The 1s peak rate, measured from T0-0.3 s, is 727 cnts/sec. Insight-HXMT/HE detected a total of 841 counts from this burst. The HXMT/HE light curve can be found here: https://www.bursthub.cn/gcn/2026/hxmtgrb260710A.png All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the regular mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://hxmten.ihep.ac.cn/ View this GCN Circular online at https://gcn.nasa.gov/circulars/45144. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43358] Fermi-LAT Gamma-ray Observations of IceCube-260704A
by GCN Circulars 13 Jul '26

13 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45143 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-260704A DATE: 26/07/13 06:35:17 GMT FROM: Leo Pfeiffer at University of Würzburg <pfeiffer.leo(a)gmail.com> S. Garrappa (Weizmann Institute of Science), L. Pfeiffer (Univ. of Wuerzburg), S. Buson (DESY, Univ. of Wuerzburg), J. Valverde (Marquette University) and C. Bartolini (University of Trento, INFN Bari) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC260704A neutrino event (GCN 45075) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The IceCube event was detected on 2026-07-04 at 07:16:58.19 UTC (T0) with J2000 position RA = 320.67 (+0.57, -0.55) deg, Decl. = +34.14 (+0.45, -0.47) deg, 90% PSF containment. No cataloged >100 MeV gamma-ray sources are located within the 90% IC260704A localization error (4FGL-DR4; The Fourth Fermi-LAT catalog Data Release 4, The Fermi-LAT collaboration 2023, arXiv:2307.12546). We searched for the existence of intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (> 100 MeV) within the IC260704A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC260704A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 3.4e-10 ph cm^-2 s^-1 for ~18-years (2008-08-04 / T0), <1.9e-08 (<1.2e-07) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For this source the Fermi-LAT contact person is Simone Garrappa (simone.garrappa at weizmann.ac.il). The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/45143. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43357] IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 12 Jul '26

12 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45142 SUBJECT: IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube DATE: 26/07/12 18:01:14 GMT FROM: Alicia Mand at IceCube/UW-Madison <aemand(a)wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-260708A (https://gcn.nasa.gov/circulars/45120) in a time range of 1000 seconds centered on the alert event time (2026-07-08 17:09:22.551 UTC to 2026-07-08 17:26:02.551 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-260708A. We report a p-value of 1.00 in this time window. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, ranges from 3.4 to 3.8 GeV cm^-2 within the 90% spatial containment region of IceCube-260708A in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 1e+04 GeV and 2e+06 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2026-07-07 17:17:42.551 UTC to 2026-07-09 17:17:42.551 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, ranges from 3.3 to 3.8 GeV cm^-2 within the 90% spatial containment region of IceCube-260708A in a 2 day time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) View this GCN Circular online at https://gcn.nasa.gov/circulars/45142. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43356] IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 12 Jul '26

12 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45141 SUBJECT: IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 26/07/12 13:57:38 GMT FROM: cristobal.zilleruelo.canas(a)desy.de The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 26-07-12 at 11:06:48.98 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_BRONZE alert stream. Documentation regarding the alert streams and their astrophysical purity can be found here: https://gcn.nasa.gov/missions/icecube. This alert has an estimated false alarm rate of 0.147 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/142854_16534371.amon) more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 26-07-12 Time: 11:06:48.98 UT RA: 200.11 (+0.7/-0.66 deg 90% PSF containment) J2000 Dec: 48.29 (+0.47/-0.44 deg 90% PSF containment) J2000 As announced in GCN Circular 43419 (https://gcn.nasa.gov/circulars/43419) IceCube alert notices for high-energy track alerts are now also streamed via Kafka. IceCube Gold/Bronze track alerts are available on the Kafka topic 'gcn.notices.icecube.gold_bronze_track_alerts'. The probability distribution of the true neutrino direction, allowing the extraction of precise 90% containment regions around the best-fit direction, is now available for revised reconstruction of high-energy track alerts. The corresponding sky map is distributed as a FITS file and follows the explicit naming convention IceCube-YYMMDDX, where YYMMDD indicates the date of the event and X is a letter distinguishing multiple alerts on the same day. The download link is provided through the GCN schema distributed via Kafka. Detailed documentation describing the alert distribution, schemas, and probability maps is available at: https://gcn.nasa.gov/missions/icecube. No known gamma-ray sources listed in the Fermi LAT 16-year Source List (FL16Y) are located within the 90% uncertainty region of this event. We report here sources within the 90% confidence contour available in the multi-order probability map, rather than those selected using the simplified rectangular error-box reported in this Circular. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu View this GCN Circular online at https://gcn.nasa.gov/circulars/45141. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43355] GRB 260708A: LCO optical observations
by GCN Circulars 11 Jul '26

11 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45140 SUBJECT: GRB 260708A: LCO optical observations DATE: 26/07/12 05:22:33 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Y.Y. Shi (GXU), C. Wu, L.P. Xin (NAOC), A. Saccardi, D. Turpin(CEA/Irfu) report on behalf of the SVOM mission team: We observed the field of the GRB 260708A detected by Fermi/GBM(Fermi GBM team, GCN 45115; GCN 45124) and Fermi/LAT (Holzmann Airasca et al., GCN 45117) with the LCO 1m telescope at Cerro Tololo Inter-American Observatory equipped with the Sinistro instrument. Our observation started on 2026-07-11 at 23:37:53 UT (about 3.56 day after the trigger) and we obtained 3x200 s exposures in the SDSS g, r and i filters. The optical counterpart (Shilova et al., GCN 45123; Freeberg et al., GCN 45127) is clearly detected in our images. We measure the following magnitudes calibrated against the UCAC4 catalog, and not corrected for Galactic extinction: g = 19.56 +/- 0.02 AB (mid-time 3.56 day after the trigger); r = 19.21 +/- 0.02 AB (mid-time 3.60 day after the trigger); i = 19.17 +/- 0.03 AB (mid-time 3.59 day after the trigger). It appears to be fading compared with the results reported by Shilova et al. (GCN 45123) and Freeberg et al.(GCN 45127). This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/45140. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43354] EP260711a: Einstein Probe detection of an X-ray transient
by GCN Circulars 11 Jul '26

11 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45139 SUBJECT: EP260711a: Einstein Probe detection of an X-ray transient DATE: 26/07/12 03:24:47 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.Wu (NJU), G. Y. Zhao (SYSU), H. W. Peng (THU), and H. Sun (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of a fast X-ray transient, designated EP260711a, by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission . The transient was identified in the telemetry data. The transient started at 2026-07-11T09:19:04 (UTC) and lasted for about 75s, with a peak flux of ~ 1.52 x 10^(-9) erg cm^-2 s^-1 in 0.5-4 keV. The position of the transient is R.A. = 213.2511 deg, Dec. = -58.8603 deg (J2000), with an uncertainty radius of 2.85 arcmin in radius (90% confidence level, including both statistical and systematic uncertainties). There are no known X-ray sources in the WXT error circle. The average WXT 0.5-4 keV spectrum can be fitted by an absorbed power-law model with a fixed Galactic hydrogen column density of 1.30 (-0.58/+2.27) ×10^22 cm^-2 and a photon index of 2.49 (-1.29/+1.59). The derived average unabsorbed 0.5-4 keV flux is 2.31 (-1.18/+7.48) x 10^(-10) erg cm^-2 s^-1. The uncertainties are at the 90% confidence level for the above parameters. Follow-up observations by EP-FXT will be arranged. Launched on 2024 January 9, Einstein Probe is a space-based X-ray observatory designed to monitor the dynamic X-ray sky and perform rapid follow-up observations of newly discovered transients (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45139. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43353] The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
by GCN Circulars 11 Jul '26

11 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45135 SUBJECT: The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg DATE: 26/07/11 01:06:54 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.-H. I. Yin (HKU), R. Shi (PMO, CAS), F.-F. Song (YNAO, CAS), Y. Wu (NJU) and C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709274666 at the time of 2026-07-10T18:07:01, is likely a new outburst associated with CV SS Cyg. The estimated flux of the outburst is around 3.2 x 10^(-10) erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 5 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/45135. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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