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

[vsnet-grb-info 37908] GRB 250327B: SVOM/VT optically bright counterpart
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39890 SUBJECT: GRB 250327B: SVOM/VT optically bright counterpart DATE: 25/03/27 22:50:19 GMT FROM: Liping Xin at NAOC, SVOM <xlp(a)nao.cas.cn> L.P. Xin, Y. L. Qiu, H. L. Li, C. Wu (NAOC),J. T. Palmerio(CEA/Irfu), Z. H. Yao, Y. Xu, P. P. Zhang, W. J. Xie, J. Wang, X. H. Han, Y. J. Xiao, H. B. Cai, J. Y. Wei (NAOC), Laurent Bouchet, Hui Yang(IRAP) report on behalf of the SVOM team: SVOM performed an automatic slew on the burst triggered by SVOM/ECLAIRs (Bouchet et al., GCN 39888). SVOM/VT began observing the field automatically with the slew of the platform triggered on-board, in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. With VHF downlinked data, a very bright uncatalogued source was found in both channels, and brightening in the first and second sequences, compared to DESI catalog. The coordinates are R.A =11:47:06.70, DEC.=+29:50:24.8 Error=0.5 arcseconds. J2000 The magnitude is VT_B~15.8 mag(AB) and VT_R~14.2 mag(AB) in the first sequence with the mid time of 461 seconds after the burst. The coordinates and the brightness are consistent with the candidate reported (Moskvitin et al., GCN 39889). We proposed that this is the optical counterpart of the burst. 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/39890. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37907] GRB 250327B: SAO RAS optical candidate
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39889 SUBJECT: GRB 250327B: SAO RAS optical candidate DATE: 25/03/27 22:33:49 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. S. Moskvitin, O. I. Spiridonova (SAO RAS), A. S. Pozanenko (IKI) report on behalf of a larger collaboration. We observed the field of the field of the SVOM GRB 250327B (Bouchet et al., GCN 39888) with the SAO RAS 1-m telescope Zeiss-1000. The observations started on 21:28:15 UT (~17 minutes after SVOM trigger) We found a bright uncatalogued source with R = 14.1 +/- 0.1 (calibrated against R2 magnitudes of nearby USNO-B1 stars) and the coordinates R.A. = 11:47:06.72 Dec. = +29:50:24.7 (+/- 0".5, Epoch = 2000.0) The observations are ongoing. View this GCN Circular online at https://gcn.nasa.gov/circulars/39889. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37906] GRB 250327B: SVOM detection of a burst
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39888 SUBJECT: GRB 250327B: SVOM detection of a burst DATE: 25/03/27 22:12:14 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Laurent Bouchet, Hui Yang, Olivier Godet, Marius Brunet (IRAP), Clara Plasse (CEA) on behalf of the SVOM mission team. SVOM/ECLAIRs triggered on the gamma-ray burst GRB 250327B (SVOM burst-id sb25032706) starting at 2025-03-27T21:11:27 UTC (Tb). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 10 alerts. IMT provided the alert with the best signal-to-noise-ratio (SNR) of 12.05 in the [8-120] keV energy band over a time window of 40.96 seconds starting at Tb. The light curve shows that the burst duration is about 300 s and the burst is still detected after the slew. The localization of the best alert is R.A., Dec 176.7763, 29.8765 degrees (J2000) with a 90% C.L. radius of 6.70 arcminutes (including systematic error of 2 arcminutes added in quadrature). SVOM slewed to the burst. MXT began observing the field at 2025-03-27T21:14:41 UTC, 193 seconds after Tb. Using onboard processed data we found an uncatalogued X-ray source located at R.A., Dec 176.788, 29.832 degrees: RA (J2000) = 11h47m09.15s DEC (J2000) = 29d49m55.57s with a 90% C.L. radius of 25 arcseconds. This MXT location is within the ECLAIRs error circle. This position may be improved as more data is received. VT began observing the field after the slew. The analysis of the recorded images will be published in a future circular gathering information on the follow-up of the SVOM optical instruments. 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. The Burst Advocate (BA) on shift for this burst is Hui Yang: hui.yang(a)irap.omp.eu. Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst. View this GCN Circular online at https://gcn.nasa.gov/circulars/39888. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37905] FRB 20250316A: Gemini Imaging and Spectroscopy of the Sub-arcsecond Localization Region of FRB 20250316A
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39887 SUBJECT: FRB 20250316A: Gemini Imaging and Spectroscopy of the Sub-arcsecond Localization Region of FRB 20250316A DATE: 25/03/27 21:54:43 GMT FROM: Wen-fai Fong at Northwestern University <wfong(a)northwestern.edu> S. Simha (U. Chicago-Northwestern), T. Eftekhari (Northwestern) report on behalf of the CHIME/FRB Collaboration: The CHIME/FRB Collaboration reports on optical imaging and spectroscopy of the sub-arcsecond CHIME Outrigger localization (ATel #17114, GCN #39886) of the nearby, bright FRB 20250316A (ATel #17081). We obtained deep g-band observations starting at 24 March 2025 12:39:44 UT (PI: T. Eftekhari; 15 x 120-sec exposures) with the Gemini-North Multi-Object Spectrograph (GMOS-N) mounted on the 8-m Gemini North telescope at Maunakea, Hawai'i. Observations were taken in clear conditions with an average airmass of 1.6 and seeing of 0.8". We do not detect any strong, possible transient (point source) optical emission at the FRB location (1-sigma; ATel #17114) and measure a 3-sigma point-source limiting magnitude at this location of g > 23.8 mag (AB). However, we detect a clump of extended optical emission in the host galaxy, offset from the FRB localization region by ~1.2" (measured from the brightest pixel in the g-band image). At a distance to NGC 4141 of ~40 Mpc, the corresponding projected physical distance between the FRB and this clump is ~250 pc. We also obtained long-slit optical spectroscopy with GMOS-N starting at 25 March 2025 10:41:44 (PI: T. Eftekhari; 8 x 900-sec exposures) at an airmass of ~1.33. We used a 1" slit width, the B480 grating, and the GG455 blocking filter at central wavelengths of 640 and 650 nm. The slit was oriented at a position angle of 10.6 degrees East of North to cover both the FRB localization region and the nearby extended optical emission. While we do not detect any transient spectral features or features at the FRB position, we detect strong nebular emission from the nearby optical clump, including H-beta, H-alpha, and [OIII] at a common redshift of z~0.0065, consistent with emission from a star-forming region within the host. We thank Gemini Observatory staff, including Jennifer Andrews, for assistance with planning and executing the observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39887. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37904] FRB 20250316A: The sub-arcsecond localization of FRB 20250316A using CHIME/FRB Outriggers coincides with reported X-ray counterparts
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39886 SUBJECT: FRB 20250316A: The sub-arcsecond localization of FRB 20250316A using CHIME/FRB Outriggers coincides with reported X-ray counterparts DATE: 25/03/27 21:19:58 GMT FROM: shiona(a)mit.edu We have derived a sub-arcsecond VLBI localization for FRB 20250316A (see ATel #17081, ATel #17086; this is the first such localization using the full CHIME/FRB Outriggers array. This consists of the CHIME core and the KKO Outrigger (Lanman et al. 2024) near Penticton, BC, and two additional Outrigger stations at Green Bank Observatory (GBO) and Hat Creek Radio Observatory (HCO). The position below is consistent with the ~10" position of the potential X-ray counterpart EP J120944.2+585060 detected by the Einstein Probe (ATel #17100) but is inconsistent with the 90% confidence interval reported from Swift/XRT observations (ATel #17109). We derive our position by referencing delays on each of the three CHIME-Outrigger baselines to nearby in-beam International Celestial Reference Frame (ICRF) calibrators observed simultaneously with the FRB (Andrew et al. 2024). On all CHIME-Outrigger baselines, we phase reference our visibilities to the calibrator RFC J1204+5202 (https://astrogeo.org/sol/rfc/rfc_2024b/; Petrov & Kovalev 2025), located ~6 degrees away from the FRB. Five additional in-beam ICRF calibrators were observed on all three baselines between CHIME and its Outriggers, which we use to derive a representative error budget for the FRB localization. The calibrators completely surround the FRB, spanning ~+/- 1 degree in hour angle and +50/-20 degrees in declination relative to CHIME zenith, while the FRB is located ~0.2 degrees east and ~10 degrees north of CHIME zenith. We check for imperfect calibrator selection and direction-dependent effects by 1) calibrating the target to all other usable calibrators, and 2) calibrating known calibrator positions to other calibrators, which maximizes on-sky angular separations. Both procedures give RMS delay errors no larger than 1 ns, 3 ns, and 6ns on the CHIME-KKO, CHIME-HCO and CHIME-GBO baselines, respectively. This yields the following 1-sigma (stat+sys) localization ellipse for the location of FRB 20250316A: Right Ascension = 12h09m44.31s Declination = +58d50m56.70s a_err = 150 milliarcsec b_err = 100 milliarcsec theta = 2.4 degrees East of North All coordinates are in the ICRF. We have included our one-sigma localization contour over the Epoch 1 r-band MMT image reported in ATel #17112. We note that to account for astrometric offsets due to optical-radio reference frame ties, we have inflated our localization errors in the plot by 150mas (added in quadrature). The full four-station array is still being commissioned, and its astrometric performance will be fully characterized in an upcoming work. However, we note that the error from our bootstrapping procedure is consistent with our archival test localizations of over 200 ICRF calibrators and well-localized pulsars at similar target-calibrator separations and at cross-correlation signal-to-noise ratios lower than those in the dataset used here. Furthermore, the abundance of in-beam calibrators may enable additional improvements on the preliminary position quoted here. Follow-up observations are strongly encouraged to definitively establish whether EP J120944.2+585060 is spatially coincident with FRB 20250316A, and to characterize the nature of this potential X-ray counterpart. Link to MMT Image https://storage.googleapis.com/chimefrb-dev.appspot.com/FRB20250316A/FRB202… View this GCN Circular online at https://gcn.nasa.gov/circulars/39886. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37903] GRB 250327A: J-band observations with WINTER
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39885 SUBJECT: GRB 250327A: J-band observations with WINTER DATE: 25/03/27 19:40:58 GMT FROM: Geoffrey Mo at MIT <gmo(a)mit.edu> Geoffrey Mo (MIT), Benjamin Schneider (LAM), Tomas Ahumada (Caltech), Danielle Frostig (CfA), Viraj Karambelkar (Caltech), Robert Stein (UMD), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report: We observed the field of GRB 250327A (Fermi GBM Team, GCN 39876; Parsotan et al., GCN 39877, Kienlin et al., GCN 39882) in the near-infrared J-band with the Palomar 1-m telescope, equipped with the 1-square degree WINTER camera (Lourie et al. 2020, Frostig et al. 2024). Observations were triggered automatically and began at 2025-03-27T07:41:48 UTC (12 min after the GRB), consisting of 5 x 120 s exposures. The images were processed using the WINTER data reduction pipeline implemented with mirar (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565). We do not detect a source at the SVOM/VT counterpart location (Xin et al., GCN 39884), and also do not detect any new sources in the Swift/BAT localization after visual comparison to archival PanSTARRS-1 (Chambers et al. 2016) y-band imaging. This is consistent with other observations (Ducoin et al., GCN 39878; Becerra et al., GCN 39879; Lipunov et al., GCN 39880; Lipunov et al., GCN 39881). We obtain the following 5-sigma upper limit: J ~ 18.3 mag (AB). WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research. View this GCN Circular online at https://gcn.nasa.gov/circulars/39885. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37902] GRB 250327A: SVOM/VT optical candidate
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39884 SUBJECT: GRB 250327A: SVOM/VT optical candidate DATE: 25/03/27 16:42:22 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> L.P. Xin (NAOC), J. T. Palmerio (CEA), L. Zhang (IHEP), Y.D. Hu (GXU), X.L. Chen (YNU), Y. L. Qiu, H.L. Li., C. Wu, Z.H. Yao, Y.N. Ma, X.H. Han, H.B. Cai, J.Y. Wei (NAOC), B. Cordier (CEA), report on behalf of the SVOM/VT team: SVOM performed a Target of Opportunity observation of GRB 250327A (Fermi GBM team, GCN 39876; Parsotan et al., GCN 39877). SVOM/VT began observing the field at 2025-03-27T11:25:40.50 UT, ~3.9 hours after the Swift/BAT trigger, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. An uncatalogued candidate is detected inside the Swift/BAT error circle at ra=248.18018, dec=61.63347 (J2000), corresponding to: RA (J2000) = 16:32:43.2 Dec (J2000) = +61:38:00.5 with an uncertainty of 1.0 arcsec. This source is not present in the archival Legacy Survey. The source is detected in the VT_R stacked image with exposure time of 47x60 seconds with VT_R = 22.8 +/- 0.3 mag (AB). The 3 sigma upper limit in the VT_B is 23.4 mag (AB). We thank D.B. Malesani for helpful discussion. 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/39884. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37901] FRB 20250316A: Pan-STARRS r and i-band imaging and photometry
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39883 SUBJECT: FRB 20250316A: Pan-STARRS r and i-band imaging and photometry DATE: 25/03/27 15:42:08 GMT FROM: James Gillanders at University of Oxford <jhgillanders.astro(a)gmail.com> J. H. Gillanders (Oxford), M. Huber, K. C. Chambers (IfA, Univ. Hawaii), S. J. Smartt, K. W. Smith, S. Srivastav (Oxford), M. Nicholl, D. Young, M. Fulton (QUB), T.-W. Chen (NCU, Taiwan) A. S. B. Schultz, T. de Boer, J. Fairlamb, G. Paek, C. C. Lin, T. Lowe, E. Magnier, P. Minguez, I. A. Smith, R. J. Wainscoat (IfA, Univ. Hawaii). We observed the field of FRB 20250316A (Ng et al., ATel 17081) and EP J120944.2+585060 (Sun et al., ATel 17100, GCN 39834) using the Pan-STARRS telescope system (Chambers et al., 2016, arXiv e-prints, 1612.05560) on MJD 60757.42 (2025-03-23 10:04 UTC), ~7.06 days after the FRB detection (Ng et al., ATel 17081). The Pan-STARRS system consists of two 1.8m telescope units located at the summit of Haleakala on the Hawaiian island of Maui, employing an SDSS-like filter system denoted as grizy, and a broad w-filter, which is a composite of the gri-filters. Our observation consisted of 6x150s exposures in i-band, and 3x150s in r-band. The images were processed with the Pan-STARRS pipeline, where they underwent astrometric and photometric calibration, and stacking (Magnier et al., 2020a, ApJS, 251, 3; Magnier et al., 2020b, ApJS, 251, 6; Waters et al., 2020, ApJS, 251, 4). From these stacked target images, which cover the entire localisation region of FRB 20250316A (Leung et al., ATel 17086) and the EP-FXT error region of EP J120944.2+585060 (Sun et al., ATel 17100, GCN 39834), we do not detect any new optical sources down to 5-sigma limiting AB magnitudes of r~23.5 and i~23.5. These non-detections are consistent with previously reported observations by Becerra et al., ATel 17082, GCN 39853; Niino et al., ATel 17084; Hashimoto ATel 17095; Yang et al., ATel 17101; Troja et al., ATel 17109, GCN 39869; Aryan et al., GCN 39839; Pereyra et al., GCN 39858; Jiang et al., GCN 39864. View this GCN Circular online at https://gcn.nasa.gov/circulars/39883. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37900] GRB 250327A: Fermi GBM observation
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39882 SUBJECT: GRB 250327A: Fermi GBM observation DATE: 25/03/27 14:52:00 GMT FROM: Andreas von Kienlin at MPE <azk(a)mpe.mpg.de> A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 07:30:06.33 UT on 27 March 2025, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 250327A (trigger 764753411 / 250327313), which was also detected by the Swift/BAT (Parsotan et al. 2025, GCN 39877). The Fermi GBM Final Real-time Localization (GCN 39876) is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 47 degrees. The GBM light curve shows a structured emission episode with a duration (T90) of about 160 s (50-300 keV). The time-averaged spectrum from T0-1.024s to T0+90.114s is best fit by a Band function with Epeak = 480 +/- 50 keV, alpha = -1.08 +/- 0.03, and beta = -2.14 +/- 0.15. The event fluence (10-1000 keV) in this time interval is (2.97 +/- 0.07)E-05 erg/cm^2. The 1.024-sec peak photon flux measured starting from T0+0.704 s in the 10-1000 keV band is 5.08 +/- 0.23 ph/s/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/39882. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37899] Fermi GRB 250327A: Global MASTER-Net observations report
by GCN Circulars 27 Mar '25

27 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39881 SUBJECT: Fermi GRB 250327A: Global MASTER-Net observations report DATE: 25/03/27 14:01:03 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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-Tunka robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 250327A ( Fermi GBM team, GCN 39876) errorbox 22555 sec after notice time and 22597 sec after trigger time at 2025-03-27 13:46:44 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 56 deg. The sun altitude is -20.9 deg. The galactic latitude b = 41 deg., longitude l = 93 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2825101 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 22688 | 2025-03-27 13:46:44 | MASTER-Tunka | (16h 33m 04.03s , +61d 29m 19.4s) | C | 180 | 19.1 | 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/39881. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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