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[vsnet-grb-info 39957] GRB 250919A: Glowbug gamma-ray detection
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41891 SUBJECT: GRB 250919A: Glowbug gamma-ray detection DATE: 25/09/19 18:58:32 GMT FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil> C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report: The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 250919A, which was also detected by Fermi/GBM (GCN 41874, 41881, 41890), SVOM/GRM (GCN 41882), and NuSTAR (GCN 41888), and associated with the Einstein Probe transient EP250919a (GCN 41879). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2025-09-19 00:28:56.288 with a duration of 32.1 s and a total significance of about 14.5 sigma. The burst originated toward the Nadir side of Glowbug and was detected despite passing through the passive material from the H9 pallet and internal passive material/shielding within Glowbug. The observed light curve comprises two primary peaks at ~T0+24s and ~T0+28s. Note that data from ~T0+30s to +38s suffered from deadtime in various detectors. The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS. Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS, and operated until 2024 April when it was put in safe storage on orbit. Glowbug was recently removed from storage and resumed operation on 2025 September 12. [1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959 [2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O [3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108 Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/41891. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39956] GRB 250919A: Fermi GBM Observation
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41890 SUBJECT: GRB 250919A: Fermi GBM Observation DATE: 25/09/19 18:56:13 GMT FROM: oindabimukherjee(a)gmail.com O. Mukherjee (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 00:28:52.28 UT on 19 September 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250919A (trigger 779934537/250919020) which was also detected by Fermi-LAT ( A. Holzmann Airasca et al. 2025, GCN 41884), SVOM-GRM (Chen-Wei Wang et al. 2025, GCN 41882), Swift-XRT (J.P. Osborne et al., 2025, GCN 41885), EP-WXT (Y.F. Liang et al. 2025, GCN 41879), Swift-UVOT (S.R. Oates et al. 2025, GCN 41886), Gemini/GMOS-S spectroscopic redshift z = 1.145 (A. J. Levan et al. 2025, GCN 41883) The Fermi GBM on-ground location is consistent with the position measured by other instruments. The angle from the Fermi LAT boresight is 56 degrees. The GBM light curve consists of a very bright emission episode, followed by a fainter second emission episode, with a total duration (T90) of about 129.3 s (50-300 keV). The time-averaged spectrum from T0+3 to T0+190 s is best fit by a Band function with Epeak = 476 +/- 6 keV, alpha = -0.88 +/- 0.01, and beta = -2.39 +/- 0.04. The event fluence (10-1000 keV) in this time interval is (4.36 +/- 0.002)E-04 erg/cm^2. The 1-sec peak photon flux measured starting from T0+33 s in the 10-1000 keV band is 115.2 +/- 0.7 ph/s/cm^2. The time-averaged spectrum of the main pulse from T0+3 to T0+58 s is best fit by a Band function with Epeak = 475 +/- 5 keV, alpha = -0.7 +/- 0.01, and beta = -2.38 +/- 0.03. The event fluence (10-1000 keV) in this time interval is (2.56 +/- 0.01)E-04 erg/cm^2. The time-averaged spectrum of the second pulse from T0+111 to T0+190 s is best fit by a Band function with Epeak = 220 +/- 12 keV, alpha = -1.12 +/- 0.02, and beta = -1.93 +/- 0.03. The event fluence (10-1000 keV) in this time interval is (5.77 +/- 0.05)E-05 erg/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/41890. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39955] Fermi GRB 250918A: Global MASTER-Net observations report
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41889 SUBJECT: Fermi GRB 250918A: Global MASTER-Net observations report DATE: 25/09/19 18:30:47 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), C.Francile, 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 250918A ( Fermi GBM team, GCN 41865) errorbox 1 days 18846 sec after notice time and 1 days 18882 sec after trigger time at 2025-09-19 17:47:00 UT, with upper limit up to 15.6 mag. Observations started at twilight. The observations began at zenith distance = 60 deg. The sun altitude is -16.5 deg. The galactic latitude b = 38 deg., longitude l = 340 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2994371 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 105313 | 2025-09-19 17:47:00 | MASTER-SAAO | (14h 44m 17.11s , -15d 37m 24.9s) | C | 60 | 15.6 | 105313 | 2025-09-19 17:47:00 | MASTER-SAAO | (14h 46m 06.96s , -15d 52m 16.6s) | C | 60 | 14.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/41889. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39954] GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41888 SUBJECT: GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission DATE: 25/09/19 18:19:52 GMT FROM: Gaurav Waratkar at Caltech <gauravwaratkar(a)iitb.ac.in> G. Waratkar (Caltech) and B. Grefenstette (Caltech) report on behalf of the NuSTAR Search for INteresting Gamma-ray Signals (SINGS) working group: The NuSTAR SINGS working group reports the detection of prompt emission from the long-duration GRB 250919A in both the NuSTAR CsI anti-coincidence shields. This GRB was identified through a blind search using the CsI shield rates. Details of the search algorithm will be described in a future paper. The NuSTAR SINGS algorithm triggered at 2025-09-19T00:29:12.000 (with a resolution ~5-seconds). This is consistent with the detections of GRB 250919A by Fermi/GBM (Fermi GBM Team, GCN Circ. 41874), SVOM/GRM (Wang et al., GCN Circ. 41882), associated with EP250919a detected by EP/WXT (Liang et al., GCN Circ. 41879). The NuSTAR CsI shield data are recorded at 1 Hz. The burst appears to be composed of a very bright peak lasting for ~20-s, followed 75-s later by a relatively fainter burst episode lasting for ~50-s. The peak count rate is ~9000-cps over a baseline rate of ~1,000-cps during this time period. We also see clear evidence in the signal above 100 keV in the CdZnTe detectors for the first episode. The localization from the counterpart candidate (Li et al., GCN Circ. 41877; Levan et al., GCN Circ. 41883; Airasca et al., GCN Circ. 41884; Osborne et al., GCN Circ. 41885, Oates et al., GCN Circ. 41886) at RA = 298.52, Dec = -48.83 implies an offset from the NuSTAR boresight of 33-deg and the offset from the geocenter of 74-deg. Lightcurves and analysis for this GRB can be found here: https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/reports/2025/250919A/ Information on NuSTAR SINGS can be found here: https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/ NuSTAR is a NASA Small Explorer mission led by Caltech and managed by JPL for NASA's Science Mission Directorate in Washington. View this GCN Circular online at https://gcn.nasa.gov/circulars/41888. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39953] GRB 250918A: SVOM/GRM observation
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41887 SUBJECT: GRB 250918A: SVOM/GRM observation DATE: 25/09/19 16:42:33 GMT FROM: Chenwei Wang at IHEP <cwwang(a)ihep.ac.cn> SVOM/GRM team: Chen-Wei Wang, Chao Zheng, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Feliu Lacreu (IAP), Stéphane Schanne (CEA) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by a burst GRB 250918A (SVOM trigger reference: sb25091803) at 2025-09-18T12:32:24.000 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN#41865). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multi-pulses with a T90 of 34.0 +8.0/-4.0 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250918A.png In addition, the position of this burst, as determined by Fermi/GBM (RA= 221.8, DEC= -15.9, GCN#41865), is located at about 114 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-12 to T0+30 s is best fitted by a power law function. The power law index is 2.64 +/-0.15. The event fluence (10-1000 keV) in this time interval is (3.28 +/-0.05)E-05 erg/cm^2. 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. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM point of contact for this burst is: Chen-Wei Wang (IHEP)(cwwang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/41887. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39952] GRB 250919A/EP250919A: Swift/UVOT afterglow detection
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41886 SUBJECT: GRB 250919A/EP250919A: Swift/UVOT afterglow detection DATE: 25/09/19 16:03:30 GMT FROM: Samantha Oates at University of Birmingham <samantha.oates(a)alumni.ucl.ac.uk> S. R. Oates (Lancaster U.) and R. Gupta (GSFC) report on behalf of the Swift/UVOT team: Swift/UVOT has performed follow-up observations of GRB 250919A/EP250919a (Fermi GBM team GCN 41874; Liang et al., GCN 41879, Wang et al., GCN 41882). Swift/UVOT began observations in the u band 21.4ks after the detection by Fermi/GBM (Fermi GBM team GCN 41874). A source is detected consistent with the optical counterpart reported by Li et al., (GCN 41877). The preliminary detection magnitude reported below is calculated using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373). Filter T_start(s) T_stop(s) Exp(s) Mag u 21418 23150 1705 17.14+\-0.03 The magnitude in the table is not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.057 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/41886. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39951] GRB 250919A: Swift-XRT afterglow detection
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41885 SUBJECT: GRB 250919A: Swift-XRT afterglow detection DATE: 25/09/19 14:03:29 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA), S. Lanava (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of GRB 250919A/EP250919a. We searched for X-ray sources in 1.7 ks of Photon Counting (PC) mode data. The total exposure at the position of the afterglow (see below) is 1.7 ks, obtained between T0+21.4 ks and T0+23.1 ks, taking T0 as the Fermi trigger time. An uncatalogued X-ray source is detected within the estimated 3-sigma Einstein Probe/WXT error region (35 arcsec), also consistent with the Fermi-LAT error region, and is above the RASS 3-sigma upper limit at this position, and is therefore likely the GRB afterglow. Using 1732 s of PC mode data and 1 UVOT image, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 298.55415, -48.83775 which is equivalent to: RA (J2000): 19h 54m 13.00s Dec(J2000): -48d 50' 15.9" with an uncertainty of 2.5 arcsec (radius, 90% confidence). The light curve is consistent with a constant source of mean count rate 2.3e+00 ct/sec. A power-law fit gives an index of 1.0 (+1.9, -1.0). However, given the position of this X-ray saource is consistent with the optical counterpart with a measured redshift of 1.145 (GCN 41883), as well as being above the RASS 3-sigma upper limit, we believe this to be the X-ray afterglow. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.52 (+0.13, -0.11). The best-fitting absorption column is 6.7 (+4.1, -1.6) x 10^20 cm^-2, consistent with the Galactic value of 5.1 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.5 x 10^-11 (4.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 6.7 (+4.1, -1.6) x 10^20 cm^-2 Galactic foreground: 5.1 x 10^20 cm^-2 Excess significance: <1.6 sigma Photon index: 1.52 (+0.13, -0.11) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/03000101. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/EP/EP_FIELD00075. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/41885. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39950] GRB 250919A: Fermi-LAT detection
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41884 SUBJECT: GRB 250919A: Fermi-LAT detection DATE: 25/09/19 09:21:09 GMT FROM: A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca(a)unitn.it> A. Holzmann Airasca (UniTrento and INFN Bari), N. Di Lalla (Stanford Univ.), E. Bissaldi (Politecnico and INFN Bari), S. Lopez (CNRS / IN2P3), D. Depalo (Politecnico and INFN Bari), T. Khalil (Johannesburg Univ), R. Gupta (NASA/GSFC) and F. Longo (University and INFN, Trieste) report on behalf of the Fermi-LAT Collaboration: On September 19, 2025, Fermi-LAT detected high-energy emission from GRB 250919A, which was also detected by Fermi-GBM (trigger 779934537 / 250919020, GCN 41876), EP (GCN 41879) spatially coincident but temporally offset by 1.77 hours, SVOM/GRB (GCN 41882) and Gemini/GMOS-S (GCN 41883). The best LAT on-ground location is found to be: RA, Dec = 298.52, -48.83 (J2000) with an error radius of 0.08 deg (90 % containment, statistical error only). This was 56 deg from the LAT boresight at the time of the GBM trigger (T0 = 00:28:52.28 UT). The data from the Fermi-LAT shows a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The photon flux above 100 MeV in the time interval 0 - 1.7 ks after the GBM trigger is (1.03 ± 0.14) E-5 ph/cm2/s. The estimated photon index above 100 MeV is -1.84 ± 0.09. The highest-energy photon is a 7 GeV event which is observed ~ 980 seconds after the GBM trigger. The Fermi-LAT point of contact for this burst is Oscar Wistemar (wistemar(a)kth.se) 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/41884. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39949] EP250919a/GRB 250919A: Gemini/GMOS-S spectroscopic redshift z = 1.145
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41883 SUBJECT: EP250919a/GRB 250919A: Gemini/GMOS-S spectroscopic redshift z = 1.145 DATE: 25/09/19 08:07:27 GMT FROM: Andrew Levan at Radboud University <a.levan(a)astro.ru.nl> A. J. Levan (Radboud and Warwick), J. N. D. van Dalen (Radboud), G. Corcoran (UCD), P. G. Jonker (Radboud), D. B. Malesani (DAWN/NBI and Radboud), J. A. Quirola-Vasquez (Radboud), F. E. Bauer (SSI and UTA), A. Martin-Carrillo (UCD) report on behalf of a larger collaboration: We obtained spectroscopic observations of the optical counterpart (Li et al., GCN 41877) of EP250919a (Liang et al., 41879), probably connected to GRB 250919A (Fermi GBM team, GCN 41874; Wang et al., GCN 41882; as also indicated by the consistency with the Fermi/LAT GRB localization; https://gcn.gsfc.nasa.gov/fermi_grbs.html) Observations were secured at the Gemini-South Telescope equipped with the GMOS spectrograph using grating B480, and began at 05:30 UT, approximately 3.25 hr (5 hr) after the EP (Fermi and SVOM) triggers. At this point we obtained 4x200 s observations covering the spectral range 3800-8000 AA. In the acquisition image, the optical counterpart is clearly detected with an AB magnitude r = 17.52 +- 0.02 (calibrated against nearby objects from the SkyMapper catalog, not corrected for Galactic extinction). The spectral trace is extremely bright and reveals multiple absorption features from Mg II, Mg I, Fe II, Al III, all at a common redshift of z = 1.145. We therefore suggest this is the redshift of EP250919a / GRB 250919A. We thank the staff of Gemini, in particular Karleyne Silva for the rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/41883. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 39948] GRB 250919A: SVOM/GRM observation of a very bright GRB
by GCN Circulars 19 Sep '25

19 Sep '25

TITLE: GCN CIRCULAR NUMBER: 41882 SUBJECT: GRB 250919A: SVOM/GRM observation of a very bright GRB DATE: 25/09/19 07:33:19 GMT FROM: Chenwei Wang at IHEP <cwwang(a)ihep.ac.cn> SVOM/GRM team: Chen-Wei Wang, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Jean-Luc Atteia (IRAP) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by a very bright burst GRB 250919A (SVOM trigger reference: sb25091901) at 2025-09-19T00:29:15.000 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN#41874). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multi-pulses with a T90 of 158.0 +/-6.0 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250919A.png In addition, the position of this burst, as determined by Fermi/GBM (RA= 303.5, DEC= 49.8, GCN#41874), is located at about 84 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view, but this burst still clearly detected by ECLAIRs through the shield due to the high brightness. With this localization, the time-averaged spectrum from T0-25 to T0+270 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.14 +0.03/-0.02 and the cutoff energy, parameterized as Epeak, is 610 +52/-46 keV. The event fluence (10-1000 keV) in this time interval is (3.01 +/-0.05)E-04 erg/cm^2. The localization of GRB 250919A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb250919A_amati.png 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. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM point of contact for this burst is: Chen-Wei Wang (IHEP)(cwwang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/41882. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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