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

[vsnet-grb-info 37286] LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39277 SUBJECT: LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate DATE: 25/02/11 04:56:55 GMT FROM: Hisaaki Shinkai at Osaka Institute of Technology <hisaaki.shinkai(a)oit.ac.jp> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250211be during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2025-02-11 04:35:43.152 UTC (GPS time: 1423283761.152). The candidate was found by the CWB BBH [1], GstLAL [2], and MBTA [3] analysis pipelines. S250211be is an event of interest because its false alarm rate, as estimated by the online analysis, is 1.8e-08 Hz, or about one in 1 year, 9 months. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250211be After parameter estimation by RapidPE-RIFT [4], the classification of the GW signal, in order of descending probability, is BBH (99%), Terrestrial (1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [5] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [5] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 32 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [6], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 1530 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 3638 +/- 1204 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [2] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [3] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [4] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [5] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [6] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/39277. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37285] LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39276 SUBJECT: LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification DATE: 25/02/11 04:44:56 GMT FROM: Soichiro Morisaki at U. of Tokyo <soichiro.morisaki(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S250211aa (GCN Circular 39275). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN Notice, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S250211aa Based on posterior support from parameter estimation [1], under the assumption that the candidate S250211aa is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is <1%. For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 248 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1121 +/- 258 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. (2023) arXiv:2307.13380 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe View this GCN Circular online at https://gcn.nasa.gov/circulars/39276. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37284] LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39275 SUBJECT: LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate DATE: 25/02/11 02:51:13 GMT FROM: Allen1711449(a)gmail.com The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250211aa during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2025-02-11 02:25:46.623 UTC (GPS time: 1423275964.623). The candidate was found by the CWB [1], CWB BBH [2], GstLAL [3], MBTA [4], and PyCBC Live [5] analysis pipelines. S250211aa is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.7e-18 Hz, or about one in 1e10 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250211aa After parameter estimation by RapidPE-RIFT [6], the classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that the lighter compact object is consistent with a neutron star mass (HasNS) is <1%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] Both HasNS and HasRemnant consider the support of several neutron star equations of state. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 1%. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 34 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], distributed via GCN notice about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 356 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1358 +/- 352 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. (2023) arXiv:2305.05625 [4] Aubin et al. CQG 38, 095004 (2021) doi:10.1088/1361-6382/abe913 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Rose et al. (2022) arXiv:2201.05263 and Pankow et al. PRD 92, 023002 (2015) doi:10.1103/PhysRevD.92.023002 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/39275. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37283] GRB 250207A: Skynet optical afterglow observations
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39274 SUBJECT: GRB 250207A: Skynet optical afterglow observations DATE: 25/02/11 01:35:36 GMT FROM: dschlekat(a)unc.edu Donovan Schlekat, Dylan Dutton, Daniel Reichart, Joshua Haislip, and Vladimir Kouprianov report on behalf of the Skynet Robotic Telescope Network at the University of North Carolina at Chapel Hill. We observed the field of GRB 250207A detected by Fermi (The Fermi GBM Team, GCN 39181) and Swift (Ferro et al., GCN 39182; Osborne et al., GCN 39217; Melandri et al., GCN 39221; Moss et al., GCN 39245) with two of Skynet's PROMPT telescopes located at the Cerro Tololo Inter-American Observatory. The observation began at 01:20:03 UT on February 7 2025, roughly 4 minutes after the Swift-BAT trigger and lasted for around 14 minutes until the field was no longer observable. Observations were performed in the B, V, R, and I bands. Exposure lengths were calculated using our automated exposure length scaling model. We detect the optical afterglow (Ferro et al., GCN 39182; Angulo et al., GCN 39186; Kuin & Ferro, GCN 39199; Brivio et al., GCN 39202; Jelinek et al., GCN 39209; Ferro et al., 39212; Ror et al., 39250) in the V, R, and I bands. The photometry of the initial detection for each band is reported below. Tmid - T0 (s)| Telescope | Filter | Exposure (s) | Mag | Mag Error ------------------------------------------------------------------ 747.0 | PROMPT-6 | V | 22 | 16.854 | 0.064 779.0 | PROMPT-5 | R | 16 | 16.593 | 0.097 805.0 | PROMPT-6 | I | 10 | 16.570 | 0.061 Our images have been calibrated using stars from the APASS catalog. Magnitudes were not corrected for dust extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/39274. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37282] LIGO/VIRGO/KAGRA S250206dm: AT 2025bbo spectroscopic observations with NIRES on Keck II
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39273 SUBJECT: LIGO/VIRGO/KAGRA S250206dm: AT 2025bbo spectroscopic observations with NIRES on Keck II DATE: 25/02/11 01:04:26 GMT FROM: Viraj Karambelkar at Indian Inst of Tech,Bombay <karambelkarvraj21197(a)gmail.com> Viraj Karambelkar (Caltech), Tomas Ahumada (Caltech), Sam Rose (Caltech), Kaew Tinyanont (NARIT), Christoffer Fremling (Caltech), Nicholas Earley (Caltech), and Mansi Kasliwal (Caltech) report: We observed the transient AT2025bbo (GCN 39210; 39244) with the Near-Infrared Echelle Spectrograph (NIRES, Wilson et al. 2004) on the Keck II telescope on 2025-02-10 05:29:43 UTC. Our observations comprised six exposures of 300s each. The spectra were extracted using the idl package spextool (Cushing et al. 2003, Vacca et al. 2004) The spectrum shows several absorption features attributable to the host galaxy (CN, Mg I, Si I, CO absorption) at a redshift of z=0.070+/-0.001, consistent with the redshift reported in GCN 39272. No obvious features attributable to a supernova or AGN are visible. Further analysis is in progress. We thank the Keck Observatory staff (Carlos Alvarez and Rita) and the Keck II observers (Maissa Salama and Becky Jensen-Clem) for their cooperation with the Target of Opportunity observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39273. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37281] LIGO/Virgo/KAGRA S250206dm: Gemini-North spectroscopic observation of AT2025bbo and its host galaxy
by GCN Circulars 11 Feb '25

11 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39272 SUBJECT: LIGO/Virgo/KAGRA S250206dm: Gemini-North spectroscopic observation of AT2025bbo and its host galaxy DATE: 25/02/11 00:33:06 GMT FROM: James Gillanders at University of Oxford <jhgillanders.astro(a)gmail.com> M. E. Huber (IfA, University of Hawaii), J. H. Gillanders (Oxford), K. Chambers (IfA, University of Hawaii), S. J. Smartt (Oxford), M. Fulton (QUB), T.-W. Chen (NCU) and D. Magill (QUB) report on behalf of a larger collaboration: We observed the transient AT2025bbo and its host galaxy with the GMOS-N spectrograph at the Gemini-North observatory under observing program ID GN-2025A-Q-133 (PI: M. E. Huber). AT2025bbo is a transient discovered during the Pan-STARRS coverage (Young et al., GCN 39210; Smartt et al., GCN 39244) of the skymap of S250206dm, the NSBH merger event detected by the LIGO-Virgo-KAGRA (LVK) Collaboration (GCN 39175). Our epoch of observation commenced at 2025-02-10 05:44 UTC, corresponding to approximately 3.35 days after the recorded merger signal of S250206dm (LVK Collaboration, GCN 39175). We obtained 4x1200s exposures with the R400 grating, sampling a wavelength range of ~4500-9200 angstroms. The source is coincident with the nucleus of the host galaxy (Smartt et al., GCN 39244), and we extracted a spectrum which would contain both the host light and any transient flux within the slit aperture. The spectrum is that of an early-type, elliptical galaxy, consistent with the Pan-STARRS and SDSS colours. The redshift from the Mg I and Na I lines is z = 0.070 +/- 0.006 (D_L = 316 Mpc for H0 = 70 km/s/Mpc). This confirms that the galaxy lies within the estimated luminosity distance range for S250206dm from the Bilby 3D skymap (373 +/- 104 Mpc; LVK Collaboration, GCN 39231). The continuum of the spectrum does not show any obvious broad features from transient flux, nor any emission lines (e.g., H-alpha, [O III]) from AGN activity. It appears consistent with galaxy light, but further analysis is required to determine if any continuum from a transient source is present. In Smartt et al. (GCN 39244), we advised caution on the reality of this event. Detections of AT2025bbo were reported by three other teams: Liu et al. (GCN 39429), Lee et al. (GCN 39252), and Ducoin et al. (GCN 39258). Upon further investigation, we find that the publicly available Pan-STARRS 3Pi reference frame (which all teams used to subtract the host) consists of only 2x40s frames at this location. While the header of the reference stack implies 24x40s, there is significant masking in the input images around the transient/galaxy position. This can be seen by selecting the warp option in the MAST user interface to access the image stamps, to display all 24 warp images. Liu et al. (GCN 39429) also reported an i-band detection, which has a good Pan-STARRS reference (630s total). Further work is required to determine if the flux excess, which all four teams detect, is due to transient flux on the galaxy core, or an artefact of the shallow reference r-band image. We thank the staff of the Gemini Observatory for rapidly approving and executing these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39272. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37280] GRB 241128A: VIRT Optical Upper Limit
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39271 SUBJECT: GRB 241128A: VIRT Optical Upper Limit DATE: 25/02/10 20:27:27 GMT FROM: Priya Gokuldass at ERAU <gokuldap(a)my.erau.edu> R. Querrard (UVI), P. Gokuldass (ERAU), N. Orange (OrangeWave Innovative Science, LLC), B. Gendre (UVI), D. Morris (NASA), T. Lombardi (Eckerd College), F. George (ERAU), D. Smith (UVI), K. Smith (UVI), C. Watson (UVI) report: We observed the field of GRB241128A (Brivio et al., GCN 38367) with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 2024-11-29 starting at 22:47:51.703 (T-mid ~ T0 + 30.75 hrs). We performed a series of exposures in an R filter with a total exposure of 1370s. The weather conditions were partly cloudy during the hours of observation with an average airmass of 2.94. We do not detect any source within the enhanced XRT position (Beardmore et al. GCN 38374). This non-detection is consistent with reported detections (Hu et al., GCN 38371;Izzo et al., GCN 38372; Gompertz et al., GCN 38373; Akl et al., GCN 38382; Pankov et al., GCN 38383; Midavaine et al., GCN 38438; and Volnova et al., GCN 38519 ) and upper limits (Lipunov et al., GCN 38380; Shilling et al., GCN 38422; Akl et al., GCN 38382; Pankov et al., GCN 38395; Midavaine et al., GCN 38438; and Volnova et al., GCN 38519 ). We report the following 3-sigma upper limit: T_mid ||Exposure ||Filter ||Limit T+30.75 hrs || 1370 s || R || > 18.6 The limit is estimated from comparison to nearby USNO B1 stars and is not corrected for Galactic extinction. We acknowledge financial support from NASA EPSCoR award 80NNSC22M0063, NSF PAARE award 2319415, and NASA EPSCoR award 80NSSC24M0112. This message can be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39271. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37279] EP250207b: Gemini GMOS-N z-band observations
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39270 SUBJECT: EP250207b: Gemini GMOS-N z-band observations DATE: 25/02/10 17:04:14 GMT FROM: P.G. Jonker at Radboud University <p.jonker(a)astro.ru.nl> Daniele B. Malesani (DAWN/ NBI and Radboud), Andrew J. Levan (Radboud), Jonathan Quirola-Vásquez (Radboud), Peter G. Jonker (Radboud), Javi Sánchez-Sierras (Radboud), Franz Bauer (PUC) report on behalf of a larger collaboration: We obtained photometric observations of the field of the fast X-ray transient EP250207b discovered by Einstein Probe (Zhou et al., GCN 39266) with the GMOS instrument mounted on the Gemini-North telescope (PI: F. Bauer; program GN-2024B-FT-112). We obtained 6 images with 15 s exposure time each and 6 with an exposure time of 60 s each in the z-band filter beginning at 2025-02-10 10:40 UT, approximately 2.5 days after the EP/WXT trigger. Within the EP/FXT error circle, comparing our stacked image with Legacy archival images we detect no plausible optical counterpart down to the depth of the Legacy Survey observations. Image subtraction between the GMOS and the Legacy Survey data also reveals no new sources. We do note the presence of a bright galaxy within the FXT error circle. This galaxy lies at RA(J2000) = 11:10:02.67 DEC(J2000) = -07:52:12.0 and has an r-band magnitude of r = 17.2. The galaxy is detected but WISE but it is not in ALLWISEAGN, implying it is unlikely to be an AGN. Following the prescription of Bloom et al. 2002 (doi: https://link.springer.com/article/10.1007/s41114-019-0024-0) we find a probability of 0.5% of such a galaxy lying within the FXT error circle by chance. The galaxy has a photometric redshift of z = 0.074+-0.009 from Legacy Survey (Zhou et al. 2021, doi:10.1093/mnras/staa3764). We thank the staff of Gemini for their excellent support in securing these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39270. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37278] EP250207A: Upper limits from Fermi-GBM Observations
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39269 SUBJECT: EP250207A: Upper limits from Fermi-GBM Observations DATE: 25/02/10 15:39:25 GMT FROM: mariaedvige.ravasio(a)ru.nl M. E. Ravasio (Radboud Univ.), E. Burns (LSU), and P.G. Jonker (Radboud Univ.) report on behalf of the Fermi-GBM Team: Fermi-GBM had full spatial coverage of the transient EP250207A detected by EP-WXT (Li et al., GCN 39224), identified as a stellar flare (Levan et al., GCN 39218, O'Connor et al., GCN 39219, Li et al., GCN 39224). There was no Fermi-GBM onboard trigger around the EP trigger time T0=2025-02-07T15:51:17 UTC. The GBM targeted search [1], the most sensitive, coherent search for GRB-like signals, was run in the time interval [T0-50;T0+500] s, seeking signals between 64 ms and 32.768 s in duration. No signal consistent with the EP transient both temporally and spatially is identified, as confirmed by visual inspection of the data. Assuming a “soft” spectral template (Band function with Epeak = 70 keV, alpha = -1.9, beta = -3.7), and a duration of 8.192 s, we derive a sky-averaged flux upper limit of 2.8e-08 erg/cm2/s in the energy band 10-1000 keV. [1] Goldstein et al. 2019 arXiv:1903.12597 View this GCN Circular online at https://gcn.nasa.gov/circulars/39269. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37277] GRB 250210A: INTEGRAL SPI-ACS detection
by GCN Circulars 10 Feb '25

10 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39268 SUBJECT: GRB 250210A: INTEGRAL SPI-ACS detection DATE: 25/02/10 11:08:10 GMT FROM: Aishwarya L Thakur at INAF-IAPS, Rome <aishth(a)outlook.com> Patrizia Barria(a,b), Giulia Gianfagna(a), James Craig Rodi(a), Aishwarya Linesh Thakur(a), Lorenzo Natalucci(a,b), Luigi Piro(a) report: GRB 250210A was discovered by Fermi/GBM (GCN 39262, seen also by AstroSat/CZTI GCN 39267) on 2025-02-10T05:31:40 (UTC). We searched for a corresponding counterpart in the INTEGRAL/SPI-ACS data. In an SPI-ACS light curve above 80 keV, we find a signal temporally coincident with the GBM detection, having an approximate duration of ~ 40 sec. The signal consists of two pulses over this duration. The approximate peak count rate in SPI-ACS is 67,700 cts/s for E>80 keV, over a median background rate of 63,324 cts/s. This work is based on observations with INTEGRAL, an ESA project with instruments and a science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany. ----- (a) INAF/IAPS-Rome (b) ICSC National Research Centre for High-Performance Computing View this GCN Circular online at https://gcn.nasa.gov/circulars/39268. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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