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

[vsnet-grb-info 36927] GRB 250109A / EP250109a: GRBAlpha detection
by GCN Circulars 13 Jan '25

13 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38920 SUBJECT: GRB 250109A / EP250109a: GRBAlpha detection DATE: 25/01/13 11:54:38 GMT FROM: Andras Pal at Konkoly Observatory <apal(a)szofi.net> A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, M. Kolar, N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 250107D (EP/WXT detection: GCN 38864; Fermi/GBM detection: GCN 38873; Swift/BAT-GUANO detection: GCN 38900) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2025-01-09 06:17:11.3 UTC. The T90 duration measured by GRBAlpha is 0.5 s and the overall significance during T90 reaches 6.6 sigma in the ~120-400 keV band. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB250109A_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. View this GCN Circular online at https://gcn.nasa.gov/circulars/38920. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36926] GRB 250107D: GRBAlpha detection
by GCN Circulars 13 Jan '25

13 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38919 SUBJECT: GRB 250107D: GRBAlpha detection DATE: 25/01/13 11:53:21 GMT FROM: Andras Pal at Konkoly Observatory <apal(a)szofi.net> A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, M. Kolar, N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 250107D (IPN Triangulation: GCN 38880; Konus/Wind detection: GCN 38881; CALET/CGBM detection: GCN 38897; INTEGRAL/SPI-ACS peak detection at 2025-01-07 ~05:23:36 UTC) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2025-01-07 05:23:36.7 UTC. The T90 duration measured by GRBAlpha is 0.5 s and the overall significance during T90 reaches 6.6 sigma in the ~120-400 keV band. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB250107D_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. View this GCN Circular online at https://gcn.nasa.gov/circulars/38919. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36925] GRB 250106A: Swift-XRT afterglow detection
by GCN Circulars 13 Jan '25

13 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38918 SUBJECT: GRB 250106A: Swift-XRT afterglow detection DATE: 25/01/13 10:26:18 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> J.P. Osborne (U. Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. A. Williams (PSU), S. Dichiara (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has conducted further observations of the field of the SVOM/ECLAIRs-detected burst GRB 250106A. The observations now extend from T0+20.2 ks to T0+579.8 ks and have a total exposure time of 7.9 ks. Of the sources previously reported, "Source 1" is fading with >3-sigma significance, and is therefore likely the GRB afterglow. Using 2981 s of PC mode data and 3 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 = 117.23873, +63.81242 which is equivalent to: RA (J2000): 07h 48m 57.29s Dec(J2000): +63d 48' 44.7" with an uncertainty of 3.0 arcsec (radius, 90% confidence). This position is 3.4 arcmin from the SVOM/ECLAIRs position. The source is fading with alpha >0.6. A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.4 (+0.8, -0.7). The best-fitting absorption column is 3.7 (+3.4, -2.4) x 10^21 cm^-2, in excess of the Galactic value of 4.5 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 3.1 x 10^-11 (6.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.7 (+3.4, -2.4) x 10^21 cm^-2 Galactic foreground: 4.5 x 10^20 cm^-2 Excess significance: 2.2 sigma Photon index: 2.4 (+0.8, -0.7) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00021753. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/ToO_GRBs/00021753. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/38918. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36924] Fermi trigger No 758442826: Global MASTER-Net observations report
by GCN Circulars 13 Jan '25

13 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38917 SUBJECT: Fermi trigger No 758442826: Global MASTER-Net observations report DATE: 25/01/13 07:16:53 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) started inspect of the Fermi GRB250113.27 (trigger No 758442826,07h 04m 33.60s , -27d 46m 12.0s, R=6.15) errorbox 86 sec after notice time and 112 sec after trigger time at 2025-01-13 06:35:33 UT, with upper limit up to 19.0 mag. The observations began at zenith distance = 28 deg. The sun altitude is -31.0 deg. The galactic latitude b = -9 deg., longitude l = 240 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2741637 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 122 | 2025-01-13 06:35:33 | MASTER-OAFA | (07h 22m 47.71s , -30d 20m 23.7s) | C | 20 | 17.1 | 123 | 2025-01-13 06:35:34 | MASTER-OAFA | (07h 12m 10.44s , -30d 42m 28.8s) | C | 20 | 18.5 | 157 | 2025-01-13 06:36:13 | MASTER-OAFA | (07h 22m 47.78s , -30d 20m 22.3s) | C | 10 | 16.8 | 167 | 2025-01-13 06:36:13 | MASTER-OAFA | (07h 12m 10.49s , -30d 42m 28.2s) | C | 30 | 18.7 | 198 | 2025-01-13 06:36:49 | MASTER-OAFA | (07h 22m 47.77s , -30d 20m 21.5s) | C | 20 | 17.1 | 208 | 2025-01-13 06:36:49 | MASTER-OAFA | (07h 12m 10.51s , -30d 42m 27.8s) | C | 40 | 18.8 | 248 | 2025-01-13 06:37:35 | MASTER-OAFA | (07h 22m 47.82s , -30d 20m 20.3s) | C | 30 | 17.3 | 259 | 2025-01-13 06:37:35 | MASTER-OAFA | (07h 12m 10.55s , -30d 42m 27.3s) | C | 50 | 18.9 | 309 | 2025-01-13 06:38:30 | MASTER-OAFA | (07h 22m 47.86s , -30d 20m 19.2s) | C | 40 | 17.4 | 319 | 2025-01-13 06:38:31 | MASTER-OAFA | (07h 12m 10.60s , -30d 42m 26.6s) | C | 60 | 19.0 | 381 | 2025-01-13 06:39:37 | MASTER-OAFA | (07h 22m 47.91s , -30d 20m 18.3s) | C | 50 | 17.5 | 391 | 2025-01-13 06:39:37 | MASTER-OAFA | (07h 12m 10.66s , -30d 42m 26.1s) | C | 70 | 19.0 | 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/38917. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36923] EP250111a: KAIT optical observations
by GCN Circulars 12 Jan '25

12 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38916 SUBJECT: EP250111a: KAIT optical observations DATE: 25/01/12 05:08:43 GMT FROM: Weikang Zheng at UC Berkeley <weikang(a)berkeley.edu> WeiKang Zheng (UCB), Xuhui Han (NAOC), Pinpin Zhang (NAOC) and Alexei V. Filippenko (UCB) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, observed the field of EP250111a (Zhao et al., GCN 38905) starting at 02:53:32 UT on 2025-01-11, ~1.55 hr after the trigger. A set of clear (roughly R) band images were obtained. We marginally detect the optical afterglow (Fu et al., GCN 38906; Pankov et al., GCN 38913) in the 11x60s coadd image and measure its brightness to be 20.5 +/- 0.3 (Vega) at a mid time of ~2.70 hr after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/38916. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36922] GRB 250109A / EP250109a: Mephisto optical upper limits
by GCN Circulars 12 Jan '25

12 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38915 SUBJECT: GRB 250109A / EP250109a: Mephisto optical upper limits DATE: 25/01/12 04:25:54 GMT FROM: Chenxu Liu at Mephisto Team <cxliu(a)ynu.edu.cn> Xingzhu Zou, Chenxu Liu, Guowang Du, Brajesh Kumar, Tao Wang, Edoardo Lagioia, Yuan Fang, Xinlei Chen, Yu Pan (all SWIFAR, YNU), Xuhui Han, Pinpin Zhang, Liping Xin, Chao Wu (all NAOC), Xiangkun Liu, Xiaowei Liu (all SWIFAR, YNU) report on behalf of the Mephisto Team: The Mephisto team observed the field of the GRB 250109A / EP250109a (EP Team , GCN 38864, GCN 38889; Fermi GBM team, GCN 38873, GCN 38887; the Swift XRT team, GCN 38867, GCN 38899; James DeLaunay et al., GCN 38900; A. Moskvitin et al. GCN 38901; the SVOM team, GCN 38904) with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. Simultaneous uvgriz band photometric observations were conducted starting from 12:27:02 2025-01-09 UT (6.15 hr after the EP-WXT trigger) under fair observational conditions. Several frames with different exposure time were taken. No new uncatalogued optical sources were detected within the EP-WXT error circle in our stacked images of uvgriz bands. The preliminary photometry and 3 sigma upper limits are below. Start_Time(UT) | Band | Exp(s) | LimMag (AB) --------------------|------|--------|------------ 2025-01-09T12:27:02 | u | 180*2 | >20.02 2025-01-09T12:34:13 | v | 180*2 | >20.15 2025-01-09T12:27:03 | g | 50*6 | >20.64 2025-01-09T12:34:14 | r | 50*6 | >20.73 2025-01-09T12:27:02 | i | 79*4 | >20.14 2025-01-09T12:34:14 | z | 79*4 | >19.19 ------------------------------------------------------------------------------------------------- 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/38915. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36921] EP250108a: Mephisto detection
by GCN Circulars 12 Jan '25

12 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38914 SUBJECT: EP250108a: Mephisto detection DATE: 25/01/12 03:05:54 GMT FROM: Chenxu Liu at Mephisto Team <cxliu(a)ynu.edu.cn> Xingzhu Zou, Chenxu Liu, Brajesh Kumar, Xinlei Chen, Guowang Du, Tao Wang, Edoardo Lagioia, Yuan Fang, Yu Pan (all SWIFAR, YNU), Xuhui Han, Pinpin Zhang, Liping Xin, Chao Wu (all NAOC), Xiangkun Liu, Xiaowei Liu (all SWIFAR, YNU) report on behalf of the Mephisto Team: The X-ray transient EP250108a detected by EP-WXT (Li et al. GCN 38861) was confirmed with an optical counterpart by Eyles-Ferris (GCN 38878); Zhu et al., (GCN 38885); Malesani et al., (GCN 38902); Kumar et al., (GCN 38907) and L. Izzo (GCN 38861). The VLT/X-shooter spectroscopic analysis by Zhu et al. (GCN 38908) confirms the source redshift z = 0.176 and classified the transient as LFBOT (dubbed “the kangaroo”). We observed the field of EP250108a with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. Simultaneous uvgriz band photometric observations were conducted on 2025-01-09 and 2025-01-10 (0.97 day and 2.06 days after the EP-WXT trigger) under fair observational conditions. Here, we report the preliminary analysis of our images taken on 2025-01-09. An optical counterpart is clearly detected (>5σ) at the transient location identified by Eyles-Ferris (GCN 38878) in the stacked images of uvgr bands. The preliminary u-, v-, g-, r- bands PSF photometry and the 3 sigma i-, z-bands upper limits are listed below. Further analysis is in progress and multi-band observations are planned in the upcoming nights. Start_Time(UT) | Band | Exp | Mag/LimMag (AB) | Significance ------------------------|------|----------|------------------|-------------- 2025-01-09T11:45:52 | u | 180s*2 | 19.89 ± 0.23 | 6.4σ 2025-01-09T11:53:04 | v | 180s*2 | 20.02 ± 0.19 | 6.6σ 2025-01-09T11:45:53 | g | 50s*6 | 20.05 ± 0.14 | 7.8σ 2025-01-09T11:53:04 | r | 50s*6 | 20.45 ± 0.17 | 5.7σ 2025-01-09T11:45:53 | i | 79s*4 | >20.66 | < 3σ 2025-01-09T11:53:04 | z | 79s*4 | >19.92 | < 3σ ---------------------------------------------------------------------------------------- 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/38914. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36920] EP250111a: Mondy optical observation
by GCN Circulars 11 Jan '25

11 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38913 SUBJECT: EP250111a: Mondy optical observation DATE: 25/01/11 23:14:49 GMT FROM: Alexei Pozanenko at IKI, Moscow <grb.alex(a)gmail.com> N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP) report on behalf of the IKI GRB FuN collaboration: We performed optical observations of the field of EP250111a (Zhao et. al, GCN 38905; Kennea et. al, GCN 38910) in the R filter with the 1.5-meter AZT-33IK telescope of the Sayan Solar Observatory (Mondy). The observations started on 2025-01-11 11:57 UT, i.e. ~0.46 days since trigger. We detect the optical source proposed by Fu et. al, GCN 38906 as an optical transient of EP250111a. Preliminary photometry of the source is the following: Date UT start t-T0 Exp. Filter OT Err. UL(3sigma) (mid, days) (s) 2025-01-11 11:57:42 0.46301 51*70 R 21.20 0.15 21.4 View this GCN Circular online at https://gcn.nasa.gov/circulars/38913. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36919] EP250108a / AT 2025kg: LCO optical observations
by GCN Circulars 11 Jan '25

11 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38912 SUBJECT: EP250108a / AT 2025kg: LCO optical observations DATE: 25/01/11 22:31:07 GMT FROM: luca.izzo(a)inaf.it L. Izzo (INAF-OACn and DARK/NBI) reports: We observed the field of EP250108A (Li et al., GCN #38861) / AT 2025kg (the "kangaroo"; Zhu et al., GCN #38908) with the Sinistro instrument mounted on the 1-m telescope of the LCO network, located at the Sutherland Observatory, South Africa. Observations started on 2025 January 11 at 20:59 UT (3.35 days after the EP trigger). We obtained a series of 3x300 s images in the SDSS-G and SDSS-r filters. At the location of AT 2025kg (Eyles-Ferris, GCN #38878; Zhu et al., GCN #38885; Malesani et al., GCN #38902; Kumar et al., GCN #38907; Levan et al., GCN #38909) we detect the source in both stacked images. We measure preliminary magnitudes of g = 20.49 +/- 0.10 mag, and r = 20.61 +/- 0.11 mag (AB), calibrated against nearby stars from the Pan-STARRS catalog. This project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 101004719. We also acknowledge the use of the ECSnoopy package by E. Cappellaro. View this GCN Circular online at https://gcn.nasa.gov/circulars/38912. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 36918] EP250111a: Global MASTER-Net observations report
by GCN Circulars 11 Jan '25

11 Jan '25

TITLE: GCN CIRCULAR NUMBER: 38911 SUBJECT: EP250111a: Global MASTER-Net observations report DATE: 25/01/11 16:27:37 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-Kislovodsk robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the EP250111a ( EP Team et al., GCN 38905) errorbox 22034 sec after notice time and 48770 sec after trigger time at 2025-01-11 14:53:34 UT, with upper limit up to 17.1 mag. Observations started at twilight. The observations began at zenith distance = 50 deg. The sun altitude is -10.3 deg. The galactic latitude b = 20 deg., longitude l = 158 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2740256 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 48800 | 2025-01-11 14:53:34 | MASTER-Kislovodsk | (06h 27m 26.49s , +56d 59m 55.8s) | C | 60 | 16.7 | 48845 | 2025-01-11 14:53:34 | MASTER-Kislovodsk | (06h 27m 26.49s , +56d 59m 55.8s) | C | 150 | 17.1 | Coadd 48880 | 2025-01-11 14:54:54 | MASTER-Kislovodsk | (06h 27m 31.58s , +57d 00m 09.6s) | C | 60 | 16.7 | 48945 | 2025-01-11 14:56:13 | MASTER-Kislovodsk | (06h 27m 29.58s , +57d 01m 53.7s) | C | 30 | 16.4 | 48994 | 2025-01-11 14:57:03 | MASTER-Kislovodsk | (06h 27m 30.55s , +57d 00m 00.6s) | C | 30 | 16.4 | 49059 | 2025-01-11 14:57:52 | MASTER-Kislovodsk | (06h 27m 34.60s , +57d 01m 58.6s) | C | 60 | 16.7 | 49139 | 2025-01-11 14:59:12 | MASTER-Kislovodsk | (06h 27m 27.57s , +57d 01m 01.9s) | C | 60 | 16.7 | 49218 | 2025-01-11 15:00:32 | MASTER-Kislovodsk | (06h 27m 27.53s , +57d 02m 04.4s) | C | 60 | 16.7 | 49299 | 2025-01-11 15:01:52 | MASTER-Kislovodsk | (06h 27m 32.46s , +57d 01m 06.5s) | C | 60 | 16.8 | 49378 | 2025-01-11 15:03:12 | MASTER-Kislovodsk | (06h 27m 26.35s , +57d 00m 09.3s) | C | 60 | 16.8 | 49458 | 2025-01-11 15:04:31 | MASTER-Kislovodsk | (06h 27m 32.25s , +57d 00m 29.7s) | C | 60 | 16.8 | 49537 | 2025-01-11 15:05:51 | MASTER-Kislovodsk | (06h 27m 30.17s , +57d 02m 06.8s) | C | 60 | 16.8 | 49617 | 2025-01-11 15:07:11 | MASTER-Kislovodsk | (06h 27m 29.07s , +57d 00m 33.5s) | C | 60 | 16.8 | 49697 | 2025-01-11 15:08:30 | MASTER-Kislovodsk | (06h 27m 32.95s , +57d 01m 50.4s) | C | 60 | 16.8 | 49777 | 2025-01-11 15:09:51 | MASTER-Kislovodsk | (06h 27m 25.83s , +57d 01m 23.6s) | C | 60 | 16.8 | 49887 | 2025-01-11 15:11:10 | MASTER-Kislovodsk | (06h 27m 25.75s , +57d 02m 27.6s) | C | 120 | 16.9 | 50027 | 2025-01-11 15:13:30 | MASTER-Kislovodsk | (06h 27m 33.48s , +57d 01m 32.6s) | C | 120 | 17.0 | 50166 | 2025-01-11 15:15:50 | MASTER-Kislovodsk | (06h 27m 25.14s , +57d 00m 38.8s) | C | 120 | 16.9 | 50306 | 2025-01-11 15:18:10 | MASTER-Kislovodsk | (06h 27m 29.80s , +57d 00m 54.7s) | C | 120 | 16.9 | 50446 | 2025-01-11 15:20:29 | MASTER-Kislovodsk | (06h 27m 28.56s , +57d 02m 34.7s) | C | 120 | 17.0 | 50586 | 2025-01-11 15:22:50 | MASTER-Kislovodsk | (06h 27m 28.31s , +57d 01m 22.1s) | C | 120 | 17.0 | 50726 | 2025-01-11 15:25:09 | MASTER-Kislovodsk | (06h 27m 30.15s , +57d 02m 55.1s) | C | 120 | 17.0 | 50866 | 2025-01-11 15:27:29 | MASTER-Kislovodsk | (06h 27m 23.97s , +57d 02m 04.2s) | C | 120 | 16.9 | 51006 | 2025-01-11 15:29:49 | MASTER-Kislovodsk | (06h 27m 23.64s , +57d 03m 10.2s) | C | 120 | 16.9 | 51145 | 2025-01-11 15:32:09 | MASTER-Kislovodsk | (06h 27m 30.20s , +57d 02m 15.1s) | C | 120 | 16.9 | 51285 | 2025-01-11 15:34:29 | MASTER-Kislovodsk | (06h 27m 22.93s , +57d 01m 20.6s) | C | 120 | 16.9 | 51425 | 2025-01-11 15:36:49 | MASTER-Kislovodsk | (06h 27m 29.84s , +57d 01m 53.1s) | C | 120 | 16.8 | 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/38911. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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