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

[vsnet-grb-info 37968] GRB 250330A: BOOTES-7 early optical upper limit
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39949 SUBJECT: GRB 250330A: BOOTES-7 early optical upper limit DATE: 25/03/30 18:13:56 GMT FROM: I. Perez-Garcia at Institute of Astrophysics of Andalusia <ipg(a)iaa.es> I. Perez-Garcia, A. J. Castro-Tirado, E. Fernandez-Garcia, S.-Y. Wu, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy (IAA-CSIC), C. Perez del Pulgar (Univ. de Malaga), G. Garcia-Segura (Inst. de Astronomia, UNAM), M. Gritsevich (Univ. of Helsinki), D. R. Xiong (Yunnan Observatories of CAS), Y.-D. Hu (GuangXi Univ.), B.-B. Zhang (Nanjing Univ.) and A. Maury (Space, San Pedro de Atacama), on behalf of a larger collaboration, report: Following the detection of GRB 250330A by Swift/BAT (Cenko et al., GCNC [39938](https://gcn.nasa.gov/circulars/39938)) and Fermi (Fermi GRB Team, GCNC [39944](https://gcn.nasa.gov/circulars/39944)), the 0.6m BOOTES-7 robotic telescope at San Pedro de Atacama (Chile) responded to the alert on Nov. 9, 06:08:48 UT (i.e. 57s after trigger, and 70s after the event). Within the reported Swift/XRT error circle (Page et al., GCNC [39940](https://gcn.nasa.gov/circulars/39940)) , no optical transient is detected down to 17.6 mag (clear filter). On a coadd (620s) of images at 06:31:17 UT (mid exposure time; i.e. 23.8 min post burst), nothing is detected down to 19.3 mag, in agreement with the deeper VLT/FORS2 observations taken later on (Becerra et al., GCNC [39941](https://gcn.nasa.gov/circulars/39941)). We thank the staff at San Pedro de Atacama Celestial Observations for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/39949. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37967] GRB 250330A: Swift/UVOT Upper Limits
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39948 SUBJECT: GRB 250330A: Swift/UVOT Upper Limits DATE: 25/03/30 17:15:45 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18(a)psu.edu> M. H. Siegel (PSU) and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 250330A 3944 s after the BAT trigger (Cenko et al., GCN Circ. 39938). No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ. 39947) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 3944 4094 147 >21.2 white 3944 4094 147 >21.2 v 4101 4300 197 >20.0 b 4921 5109 185 >20.9 u 4716 4915 197 >20.0 w1 4511 4711 197 >21.3 m2 4306 4505 197 >19.8 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.147 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/39948. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37966] GRB 250330A: Swift-XRT afterglow detection
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39947 SUBJECT: GRB 250330A: Swift-XRT afterglow detection DATE: 25/03/30 16:52:55 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> J.P. Osborne (U. Leicester), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), D.N. Burrows (PSU), M. A. Williams (PSU), S. Dichiara (PSU), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the Swift-BAT-detected burst GRB 250330A. We searched for X-ray sources in 1.4 ks of Photon Counting (PC) mode data. The total exposure at the position of the afterglow (see below) is 5.1 ks, obtained between T0+3.9 ks and T0+28.0 ks. Two uncatalogued X-ray sources are detected within the estimated 3-sigma Swift-BAT error region (296 arcsec), of which one ("Source 1") is above the LSXPS 3-sigma upper limit at this position and fading with >3-sigma significance, and is therefore likely the GRB afterglow. Using 1474 s of PC mode data and 4 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 252.94482, -86.88053 which is equivalent to: RA (J2000): 16h 51m 46.76s Dec(J2000): -86d 52' 49.9" with an uncertainty of 2.3 arcsec (radius, 90% confidence). This position is 48 arcsec from the Swift-BAT position. The light curve can be modelled with a power-law decay with a decay index of alpha=1.01 (+0.15, -0.14). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.3 (+0.4, -0.3). The best-fitting absorption column is 4.9 (+1.9, -1.5) x 10^21 cm^-2, in excess of the Galactic value of 1.2 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.6 x 10^-11 (7.0 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 4.9 (+1.9, -1.5) x 10^21 cm^-2 Galactic foreground: 1.2 x 10^21 cm^-2 Excess significance: 3.9 sigma Photon index: 2.3 (+0.4, -0.3) If the light curve continues to decay with a power-law decay index of 1.01, the count rate at T+24 hours will be 7.8 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.8 x 10^-13 (5.4 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01299776. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/01299776. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39947. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37965] GRB 250328A: 1.6m Mephisto optical observations
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39946 SUBJECT: GRB 250328A: 1.6m Mephisto optical observations DATE: 25/03/30 16:19:25 GMT FROM: Brajesh Kumar at SWIFAR, YNU <brajesh(a)ynu.edu.cn> Brajesh Kumar, Jianhui Lian, Xinlei Chen, Xufeng Zhu, Fanchuan Kong, Yaosong Yu, Xingzhu Zou, Yu Pan, Guowang Du, Yuan Fang, Jinghua Zhang, Helong Guo, Tao Wang, Yuanpei Yang, Xiangkun Liu, Xiaowei Liu (all SWIFAR, YNU) report on behalf of the Mephisto Team: The field of SVOM/ECLAIRs-detected GRB 250328A (burst-id sb25032803; Brunet et al., GCN 39910) was observed with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. Our observations were started from 2025-03-28T18:19:29 (~1.4 hr after the trigger) under moderate sky conditions. Multiple frames in uvgriz bands were simultaneously (ugi, vrz) acquired with different exposure time. There is a marginal detection of an afterglow candidate in our stacked g and r band images at the location reported in VLT/HAWK-I observations (Schneider et al.; GCN 39919), also consistent with the XRT source #2. There is no optical detection in uviz bands. Considering the fading nature of the source reported in later epoch of observations at the same location (Schneider et al., GCN 39920; Li et al., GCN 39923; Li et al, GCN 39936), the candidate in our stacked images is likely the optical counterpart of GRB 250328A (Li et al, GCN 39936). The preliminary photometric magnitudes (without Galactic extinction correction) and 3 sigma limiting magnitudes in different bands are below: Start_Time(UT) | Band | Exp(s) | Mag/LimMag(AB) ---------------------|------|--------|-------------------- 2025-03-28T18:19:29 | u | 180*3 | >20.17 2025-03-28T18:28:23 | v | 180*4 | >21.02 2025-03-28T18:19:29 | g | 50*10 | 21.53 +/- 0.22 2025-03-28T18:28:23 | r | 50*12 | 21.44 +/- 0.15 2025-03-28T18:19:29 | i | 79*7 | >21.62 2025-03-28T18:28:23 | z | 79*8 | >20.94 ---------------------------------------------------------- Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6-m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The on-site telescope assemblage and commissioning were carried out in September 2022. The first light in all three channels was achieved on 2023 December 21. ---------------------------------------------------------- View this GCN Circular online at https://gcn.nasa.gov/circulars/39946. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37964] GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39945 SUBJECT: GRB 250329B: SVOM/COLIBRÍ (F-GFT) optical upper limit DATE: 25/03/30 15:32:15 GMT FROM: J.-G. Ducoin at CPPM <ducoin(a)cppm.in2p3.fr> Ny Avo Rakotondrainibe (LAM), Jean-Grégoire Ducoin (CPPM), Jean-Luc Atteia (IRAP), Margarita Pereyra (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Dalya Akl (AUS), Camila Angulo (UNAM), Sarah Antier (OCA), Rosa L. Becerra (U Roma), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM) report: We imaged the field of GRB 250329B detected by SVOM/ECLAIRs as trigger sb25032902, (Xie et al., GCN Circ. 39925) with the DDRAGO wide-field imager on the COLIBRÍ telescope at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir in Mexico. We observed from 2025-03-30 04:04 to 05:50 UTC (15.9 to 17.66 hours after the trigger) and obtained 80 minutes of exposure in the i filter. The data were coadded with the COLIBRÍ pipeline and analyzed in STDWeb/STDPipe (Karpov 2025), with photometric calibration against Pan-STARRS DR1. Our photometry is in the AB system and is not corrected for Galactic extinction. At the XRT localization (Beardmore et al., GCN Circ. 39939), we do not find any optical counterpart to a 3-sigma limiting magnitude of: i > 23.73. Our result is consistent with previous optical non-detections (Xie et al., GCN Circ. 39926; Chen et al., GCN Circ. 39929; Xin et al., GCN Circ. 39931; and Wu et al., GCN Circ 39935) We acknowledge the excellent support of the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and thank the COLIBRÍ and DDRAGO engineering teams. View this GCN Circular online at https://gcn.nasa.gov/circulars/39945. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37963] GRB 250330A: Fermi GBM Final Localization
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39944 SUBJECT: GRB 250330A: Fermi GBM Final Localization DATE: 25/03/30 12:59:41 GMT FROM: Utkarsh Pathak at IIT Bombay <utkarshpathak.07(a)gmail.com> The Fermi GBM team reports the detection of a likely LONG GRB "At 06:07:38.42 UT on 30 March 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250330A (trigger 765007663/250330255). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 254.96, Dec = -66.02 (J2000 degrees, equivalent to J2000 16h 51m, -86d 52'), with a statistical uncertainty of 6.9 degrees. This localization is consistent with Swift-BAT location (Cenko et al. 2025, GCN 39938) and Swift-XRT (Page et al. 2025, 39940). The angle from the Fermi LAT boresight is 46 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250330255/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250330255/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250330255/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/39944. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37962] IceCube-250330A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39943 SUBJECT: IceCube-250330A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 25/03/30 11:02:08 GMT FROM: Giacomo Sommani at Ruhr-Universität Bochum <gsommani(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2025-03-30 08:31:06.33 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. The average astrophysical neutrino purity for Bronze alerts is 30%. This alert has an estimated false alarm rate of 1.7612 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/140729_49427574.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2025-03-30 Time: 08:31:06.33 UT RA: 307.53 (+0.57, -0.47 deg 90% PSF containment) J2000 Dec: 11.07 (+0.45, -.47 deg 90% PSF containment) J2000 We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of the event. 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/39943. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37961] IceCube Alert 250330.35: Global MASTER-Net observations report
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39942 SUBJECT: IceCube Alert 250330.35: Global MASTER-Net observations report DATE: 25/03/30 10:39:28 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the IceCube Alert 250330.35 (trigger No 49427574,20h 29m 18.48s , +10d 58m 33.6s, R=0.51) errorbox 91 sec after notice time and 148 sec after trigger time at 2025-03-30 08:33:34 UT, with upper limit up to 19.2 mag. The observations began at zenith distance = 69 deg. The sun altitude is -28.6 deg. The galactic latitude b = -16 deg., longitude l = 55 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2828042 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 154 | 2025-03-30 08:33:34 | MASTER-OAFA | (20h 20m 09.80s , +10d 22m 06.8s) | C | 10 | 16.4 | 179 | 2025-03-30 08:33:34 | MASTER-OAFA | (20h 20m 09.79s , +10d 22m 06.9s) | C | 60 | 17.3 | Coadd 164 | 2025-03-30 08:33:35 | MASTER-OAFA | (20h 29m 20.45s , +10d 45m 17.7s) | C | 30 | 17.7 | 209 | 2025-03-30 08:33:35 | MASTER-OAFA | (20h 29m 20.45s , +10d 45m 17.7s) | C | 120 | 18.4 | Coadd 454 | 2025-03-30 08:33:35 | MASTER-OAFA | (20h 29m 20.44s , +10d 45m 17.7s) | C | 610 | 18.3 | Coadd 194 | 2025-03-30 08:34:10 | MASTER-OAFA | (20h 20m 10.00s , +10d 22m 13.8s) | C | 20 | 16.8 | 205 | 2025-03-30 08:34:11 | MASTER-OAFA | (20h 29m 20.56s , +10d 45m 22.0s) | C | 40 | 17.9 | 246 | 2025-03-30 08:34:57 | MASTER-OAFA | (20h 20m 10.18s , +10d 22m 21.5s) | C | 30 | 16.9 | 256 | 2025-03-30 08:34:57 | MASTER-OAFA | (20h 29m 20.73s , +10d 45m 26.7s) | C | 50 | 17.9 | 307 | 2025-03-30 08:35:53 | MASTER-OAFA | (20h 20m 10.41s , +10d 22m 29.9s) | C | 40 | 17.0 | 367 | 2025-03-30 08:35:53 | MASTER-OAFA | (20h 20m 10.41s , +10d 22m 29.9s) | C | 160 | 17.5 | Coadd 318 | 2025-03-30 08:35:54 | MASTER-OAFA | (20h 29m 20.96s , +10d 45m 32.0s) | C | 60 | 17.9 | 398 | 2025-03-30 08:35:54 | MASTER-OAFA | (20h 29m 20.96s , +10d 45m 32.0s) | C | 220 | 18.5 | Coadd 378 | 2025-03-30 08:36:59 | MASTER-OAFA | (20h 20m 10.57s , +10d 22m 37.6s) | C | 50 | 17.1 | 389 | 2025-03-30 08:36:59 | MASTER-OAFA | (20h 29m 21.10s , +10d 45m 37.1s) | C | 70 | 18.0 | 464 | 2025-03-30 08:38:15 | MASTER-OAFA | (20h 20m 10.80s , +10d 22m 47.2s) | C | 70 | 17.0 | 475 | 2025-03-30 08:38:15 | MASTER-OAFA | (20h 29m 21.27s , +10d 45m 43.8s) | C | 90 | 17.9 | 571 | 2025-03-30 08:39:52 | MASTER-OAFA | (20h 20m 11.10s , +10d 22m 57.3s) | C | 90 | 17.3 | 696 | 2025-03-30 08:39:52 | MASTER-OAFA | (20h 20m 11.09s , +10d 22m 57.2s) | C | 340 | 17.9 | Coadd 581 | 2025-03-30 08:39:52 | MASTER-OAFA | (20h 29m 21.47s , +10d 45m 50.8s) | C | 110 | 18.2 | 751 | 2025-03-30 08:39:52 | MASTER-OAFA | (20h 29m 21.47s , +10d 45m 50.6s) | C | 450 | 18.7 | Coadd 697 | 2025-03-30 08:41:48 | MASTER-OAFA | (20h 20m 11.33s , +10d 23m 08.5s) | C | 110 | 17.3 | 707 | 2025-03-30 08:41:48 | MASTER-OAFA | (20h 29m 21.71s , +10d 45m 59.7s) | C | 130 | 17.9 | 848 | 2025-03-30 08:44:04 | MASTER-OAFA | (20h 20m 11.45s , +10d 23m 18.4s) | C | 140 | 17.5 | 858 | 2025-03-30 08:44:04 | MASTER-OAFA | (20h 29m 21.88s , +10d 46m 08.9s) | C | 160 | 18.2 | 1024 | 2025-03-30 08:46:50 | MASTER-OAFA | (20h 20m 11.60s , +10d 23m 29.1s) | C | 160 | 17.3 | 1034 | 2025-03-30 08:46:50 | MASTER-OAFA | (20h 29m 22.17s , +10d 46m 20.1s) | C | 180 | 18.0 | 1210 | 2025-03-30 08:49:56 | MASTER-OAFA | (20h 20m 11.76s , +10d 23m 40.7s) | C | 160 | 17.6 | 1370 | 2025-03-30 08:49:56 | MASTER-OAFA | (20h 20m 11.76s , +10d 23m 40.8s) | C | 480 | 18.1 | Coadd 1221 | 2025-03-30 08:49:56 | MASTER-OAFA | (20h 29m 22.37s , +10d 46m 30.8s) | C | 180 | 18.4 | 1408 | 2025-03-30 08:53:04 | MASTER-OAFA | (20h 29m 22.58s , +10d 46m 41.4s) | C | 180 | 18.4 | 1584 | 2025-03-30 08:56:10 | MASTER-OAFA | (20h 20m 12.02s , +10d 24m 01.1s) | C | 160 | 17.6 | 1594 | 2025-03-30 08:56:10 | MASTER-OAFA | (20h 29m 22.74s , +10d 46m 51.5s) | C | 180 | 18.4 | 1774 | 2025-03-30 08:56:10 | MASTER-OAFA | (20h 29m 22.75s , +10d 46m 51.5s) | C | 540 | 18.9 | Coadd 1770 | 2025-03-30 08:59:15 | MASTER-OAFA | (20h 20m 12.11s , +10d 24m 09.8s) | C | 160 | 17.6 | 1780 | 2025-03-30 08:59:16 | MASTER-OAFA | (20h 29m 22.89s , +10d 47m 00.1s) | C | 180 | 18.4 | 1956 | 2025-03-30 09:02:22 | MASTER-OAFA | (20h 20m 12.11s , +10d 24m 17.4s) | C | 160 | 17.6 | 2116 | 2025-03-30 09:02:22 | MASTER-OAFA | (20h 20m 12.11s , +10d 24m 17.3s) | C | 480 | 18.2 | Coadd 1966 | 2025-03-30 09:02:22 | MASTER-OAFA | (20h 29m 23.02s , +10d 47m 08.9s) | C | 180 | 18.6 | 2142 | 2025-03-30 09:05:28 | MASTER-OAFA | (20h 20m 12.15s , +10d 24m 26.4s) | C | 160 | 17.8 | 2152 | 2025-03-30 09:05:28 | MASTER-OAFA | (20h 29m 23.11s , +10d 47m 17.6s) | C | 180 | 18.6 | 2332 | 2025-03-30 09:05:28 | MASTER-OAFA | (20h 29m 23.11s , +10d 47m 17.6s) | C | 540 | 19.1 | Coadd 2328 | 2025-03-30 09:08:34 | MASTER-OAFA | (20h 20m 12.13s , +10d 24m 34.2s) | C | 160 | 17.7 | 2338 | 2025-03-30 09:08:34 | MASTER-OAFA | (20h 29m 23.16s , +10d 47m 25.6s) | C | 180 | 18.7 | 2514 | 2025-03-30 09:11:40 | MASTER-OAFA | (20h 20m 12.11s , +10d 24m 42.9s) | C | 160 | 17.7 | 2674 | 2025-03-30 09:11:40 | MASTER-OAFA | (20h 20m 12.11s , +10d 24m 42.9s) | C | 480 | 18.2 | Coadd 2525 | 2025-03-30 09:11:40 | MASTER-OAFA | (20h 29m 23.23s , +10d 47m 33.9s) | C | 180 | 18.6 | 2700 | 2025-03-30 09:14:46 | MASTER-OAFA | (20h 20m 11.96s , +10d 24m 49.3s) | C | 160 | 17.7 | 2710 | 2025-03-30 09:14:46 | MASTER-OAFA | (20h 29m 23.24s , +10d 47m 41.1s) | C | 180 | 18.6 | 2890 | 2025-03-30 09:14:46 | MASTER-OAFA | (20h 29m 23.24s , +10d 47m 41.1s) | C | 540 | 19.2 | Coadd 2886 | 2025-03-30 09:17:52 | MASTER-OAFA | (20h 20m 11.87s , +10d 24m 55.7s) | C | 160 | 17.7 | 2897 | 2025-03-30 09:17:52 | MASTER-OAFA | (20h 29m 23.23s , +10d 47m 47.9s) | C | 180 | 18.6 | 3073 | 2025-03-30 09:20:58 | MASTER-OAFA | (20h 20m 11.77s , +10d 25m 01.5s) | C | 160 | 17.9 | 3233 | 2025-03-30 09:20:58 | MASTER-OAFA | (20h 20m 11.77s , +10d 25m 01.5s) | C | 480 | 18.3 | Coadd 3083 | 2025-03-30 09:20:59 | MASTER-OAFA | (20h 29m 23.17s , +10d 47m 54.3s) | C | 180 | 18.8 | 3259 | 2025-03-30 09:24:05 | MASTER-OAFA | (20h 20m 11.65s , +10d 25m 07.5s) | C | 160 | 17.8 | 3270 | 2025-03-30 09:24:05 | MASTER-OAFA | (20h 29m 23.08s , +10d 48m 00.1s) | C | 180 | 18.8 | 3450 | 2025-03-30 09:24:05 | MASTER-OAFA | (20h 29m 23.08s , +10d 48m 00.1s) | C | 540 | 19.2 | Coadd 3446 | 2025-03-30 09:27:11 | MASTER-OAFA | (20h 20m 11.57s , +10d 25m 14.3s) | C | 160 | 17.8 | 3456 | 2025-03-30 09:27:12 | MASTER-OAFA | (20h 29m 22.99s , +10d 48m 06.0s) | C | 180 | 18.8 | 3631 | 2025-03-30 09:30:17 | MASTER-OAFA | (20h 20m 11.32s , +10d 25m 17.7s) | C | 160 | 17.9 | 3791 | 2025-03-30 09:30:17 | MASTER-OAFA | (20h 20m 11.32s , +10d 25m 17.7s) | C | 480 | 18.3 | Coadd 3642 | 2025-03-30 09:30:18 | MASTER-OAFA | (20h 29m 22.85s , +10d 48m 10.9s) | C | 180 | 18.9 | 3818 | 2025-03-30 09:33:23 | MASTER-OAFA | (20h 20m 11.05s , +10d 25m 20.8s) | C | 160 | 17.9 | 3828 | 2025-03-30 09:33:24 | MASTER-OAFA | (20h 29m 22.71s , +10d 48m 15.8s) | C | 180 | 18.8 | 4008 | 2025-03-30 09:33:24 | MASTER-OAFA | (20h 29m 22.70s , +10d 48m 15.8s) | C | 540 | 19.2 | Coadd 4004 | 2025-03-30 09:36:30 | MASTER-OAFA | (20h 20m 10.69s , +10d 25m 22.7s) | C | 160 | 17.7 | 4014 | 2025-03-30 09:36:30 | MASTER-OAFA | (20h 29m 22.52s , +10d 48m 19.4s) | C | 180 | 18.8 | 4191 | 2025-03-30 09:39:37 | MASTER-OAFA | (20h 20m 10.39s , +10d 25m 26.8s) | C | 160 | 17.8 | 4351 | 2025-03-30 09:39:37 | MASTER-OAFA | (20h 20m 10.39s , +10d 25m 26.8s) | C | 480 | 18.2 | Coadd 4201 | 2025-03-30 09:39:37 | MASTER-OAFA | (20h 29m 22.33s , +10d 48m 23.2s) | C | 180 | 18.7 | 4377 | 2025-03-30 09:42:43 | MASTER-OAFA | (20h 20m 10.20s , +10d 25m 32.4s) | C | 160 | 17.6 | 4387 | 2025-03-30 09:42:43 | MASTER-OAFA | (20h 29m 22.13s , +10d 48m 27.3s) | C | 180 | 18.5 | 4564 | 2025-03-30 09:45:49 | MASTER-OAFA | (20h 20m 09.80s , +10d 25m 34.1s) | C | 160 | 17.6 | 4574 | 2025-03-30 09:45:50 | MASTER-OAFA | (20h 29m 21.90s , +10d 48m 30.3s) | C | 180 | 18.5 | 4750 | 2025-03-30 09:48:56 | MASTER-OAFA | (20h 20m 09.46s , +10d 25m 36.8s) | C | 160 | 17.5 | 4910 | 2025-03-30 09:48:56 | MASTER-OAFA | (20h 20m 09.48s , +10d 25m 36.8s) | C | 480 | 17.6 | Coadd 4760 | 2025-03-30 09:48:56 | MASTER-OAFA | (20h 29m 21.60s , +10d 48m 33.2s) | C | 180 | 17.9 | 4937 | 2025-03-30 09:52:02 | MASTER-OAFA | (20h 20m 09.11s , +10d 25m 38.9s) | C | 160 | 17.2 | 5122 | 2025-03-30 09:55:08 | MASTER-OAFA | (20h 20m 08.75s , +10d 25m 41.4s) | C | 160 | 16.9 | 5308 | 2025-03-30 09:58:14 | MASTER-OAFA | (20h 20m 08.40s , +10d 25m 43.9s) | C | 160 | 16.5 | 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/39942. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37960] GRB 250330A: VLT/FORS2 Optical Observations
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39941 SUBJECT: GRB 250330A: VLT/FORS2 Optical Observations DATE: 25/03/30 10:22:23 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra(a)roma2.infn.it> Rosa Becerra (U Rome), Eleonora Troja (U Rome), Muskan Yadav (U Rome), Roberto Ricci (U Rome) report on behalf of the ERC BHianca team: We observed the field of GRB 250330A (Cenko et al., GCN 39938) with the FORS2 imager on the ESO VLT UT1 (Antu). Observations began at T+1.25 hours after the trigger and were carried out in the R filter at an average seeing of 0.7" and airmass about 2.2. Image subtraction against the SkyMapper Southern Survey (SMSS) Fourth Data Release (DR4) catalog (Onken et al., 2024) shows no new uncataloged source down to r~21.5 AB. Several fainter objects are visible within the XRT position (Page et al., GCN 39940), however, additional observations are required to assess their variability We thank the staff at the VLT for the rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39941. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37959] GRB 250330A: Prompt Swift-XRT position
by GCN Circulars 30 Mar '25

30 Mar '25

TITLE: GCN CIRCULAR NUMBER: 39940 SUBJECT: GRB 250330A: Prompt Swift-XRT position DATE: 25/03/30 09:00:27 GMT FROM: K.L. Page at U Leicester <klp5(a)leicester.ac.uk> K.L. Page and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team: Because of the location of Swift with respect to the South Atlantic Anomaly at the time of the burst, XRT began collecting Photon Counting mode data for GRB 250330A (GCN Circ. 39938) around 4 ks after the trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec = 252.9515, -86.87972 which is equivalent to RA (J2000): 16h 51m 48.36s Dec (J2000): -86d 52' 47.0" with an uncertainty of 3.9 arcsec (radius, 90% confidence). This is 47 arcseconds from the BAT position, inside the BAT error circle. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/39940. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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