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

[vsnet-grb-info 37406] Swift GRB250221.15: Global MASTER-Net OT detection
by GCN Circulars 21 Feb '25

21 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39395 SUBJECT: Swift GRB250221.15: Global MASTER-Net OT detection DATE: 25/02/21 03:43:44 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), 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 (Lomonosov MSU), O.Gress, N.Budnev(ISU), 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 GRB250221.15 60 sec after notice time and 93 sec after trigger time at 2025-02-21 03:36:10 UT. On our first (20s exposure) set we found 1 optical transient within Swift error-box (ra=59.475 dec=-15.1383 r=0.05) brighter than 18.4. T-Tmid Date Time Expt. Ra Dec Mag ---------|---------------------|-------|-----------------|-----------------|------- 103 2025-02-21 03:36:10 20 (03h 57m 51.13s , -15d 08m 00.7s) 16.5 The 5-sigma upper limit has been about 18.4mag The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39395. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37405] Swift GRB250221.15: Global MASTER-Net observations report
by GCN Circulars 21 Feb '25

21 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39394 SUBJECT: Swift GRB250221.15: Global MASTER-Net observations report DATE: 25/02/21 03:42:25 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 Swift GRB250221.15 (trigger No 1290305,03h 57m 54.48s , -15d 08m 20.4s, R=0.05) errorbox 57 sec after notice time and 93 sec after trigger time at 2025-02-21 03:36:10 UT, with upper limit up to 18.9 mag. The observations began at zenith distance = 71 deg. The sun altitude is -44.9 deg. The galactic latitude b = -45 deg., longitude l = 207 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2784839 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 103 | MASTER-OAFA | C | 20 | 18.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39394. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37404] EP250220a: Xinglong optical upper limit
by GCN Circulars 21 Feb '25

21 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39393 SUBJECT: EP250220a: Xinglong optical upper limit DATE: 25/02/21 02:21:20 GMT FROM: Xinglong Observatory at National Astronomical Observatories (NAOC), Chinese Academy of Sciences (CAS) <xinglong(a)nao.cas.cn> Yu-Zhang(NAOC), Junjie-Jin(NAOC), Haiyang-Mu(NAOC), Feng-Xiao(NAOC), Qi-Zhao(NAOC), Zhou-Fan(NAOC), Hong-Wu(NAOC) report on behalf of a large collaboration: Following the detection of EP250220a by EP-WXT (Y. L. Wang et al., GCN 39387), we observed the field of EP250220a using the 2.16-m telescope at Xinglong Observatory, NAOC. We obtained 6x600s clear-band frames with a median time of 2025-02-20T12:10:32 i.e., 10 hr after the EP trigger. No uncatalogued optical transient is detected in the stacked images within the 2.81 arcmin EP/WXT error circle (Y. L. Wang et al., GCN 39387), down to 5-sigma limiting magnitudes of clear ~ 22.6, calibrated with Pan-STARRS sources in the field. Also there is no apparent brightening for the catalogued sources within the error circle. View this GCN Circular online at https://gcn.nasa.gov/circulars/39393. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37403] Fermi Gamma-ray Burst Monitor trigger 761788229/250220993 is not a GRB
by GCN Circulars 21 Feb '25

21 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39392 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 761788229/250220993 is not a GRB DATE: 25/02/21 01:29:45 GMT FROM: rhamburg(a)usra.edu R. Hamburg (USRA) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 761788229/250220993 at 23:50:24.20 UT on 20 February 2025, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to local particles." View this GCN Circular online at https://gcn.nasa.gov/circulars/39392. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37402] GRB 250220B: Fermi GBM Final Real-time Localization
by GCN Circulars 21 Feb '25

21 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39391 SUBJECT: GRB 250220B: Fermi GBM Final Real-time Localization DATE: 25/02/21 00:00:55 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 23:50:24 UT on 20 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250220B (trigger 761788229.197974 / 250220993). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 39.3, Dec = 45.6 (J2000 degrees, equivalent to J2000 02h 37m, 45d 36'), with a statistical uncertainty of 1.0 degrees. The angle from the Fermi LAT boresight is 3.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250220993/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250220993/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250220993/… View this GCN Circular online at https://gcn.nasa.gov/circulars/39391. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37401] Fermi Gamma-ray Burst Monitor trigger 761782146/250220923 is not a GRB
by GCN Circulars 20 Feb '25

20 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39390 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 761782146/250220923 is not a GRB DATE: 25/02/20 22:35:43 GMT FROM: rhamburg(a)usra.edu R. Hamburg (USRA) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 761782146/250220923 at 22:09:01.82 UT on 20 February 2025, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to local particles." View this GCN Circular online at https://gcn.nasa.gov/circulars/39390. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37400] GRB 250220A: Fermi GBM Final Real-time Localization
by GCN Circulars 20 Feb '25

20 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39389 SUBJECT: GRB 250220A: Fermi GBM Final Real-time Localization DATE: 25/02/20 22:19:28 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 22:09:01 UT on 20 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250220A (trigger 761782146.820828 / 250220923). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 194.6, Dec = -60.9 (J2000 degrees, equivalent to J2000 12h 58m, -60d 53'), with a statistical uncertainty of 1.0 degrees. The angle from the Fermi LAT boresight is 171.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250220923/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250220923/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250220923/… View this GCN Circular online at https://gcn.nasa.gov/circulars/39389. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37399] EP250220a: Global MASTER-Net observations report
by GCN Circulars 20 Feb '25

20 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39388 SUBJECT: EP250220a: Global MASTER-Net observations report DATE: 25/02/20 16:18:36 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) was pointed to the EP250220a ( EP Team et al., GCN 39387) errorbox 228 sec after notice time and 49332 sec after trigger time at 2025-02-20 15:54:11 UT, with upper limit up to 12.9 mag. The observations began at zenith distance = 17 deg. The sun altitude is -46.1 deg. The galactic latitude b = 25 deg., longitude l = 179 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2784319 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 49363 | 2025-02-20 15:54:11 | MASTER-Tunka | (07h 33m 25.59s , +40d 01m 57.1s) | C | 60 | 12.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39388. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37398] EP250220a: EP-WXT detection of a fast X-ray transient
by GCN Circulars 20 Feb '25

20 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39387 SUBJECT: EP250220a: EP-WXT detection of a fast X-ray transient DATE: 25/02/20 15:47:51 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y. L. Wang (NAOC, CAS), D. F. Hu (PMO, CAS), B. B. Zhang (BNU), P. Y. Han, C. X. Zhang (HUST), Y. Liu (NAOC, CAS) report on behalf of the Einstein Probe team: We report on the detection of a fast X-ray transient by EP-WXT, designated EP250220a. The WXT position of the source is R.A. = 113.400 deg, DEC = 39.795 deg (J2000) with an uncertainty of 2.81 arcmin in radius (90% C.L. statistical and systematic). The flare starts from 2025-02-20T02:11:59 (UTC), lasting for about 150 seconds. The average 0.5-4 keV spectrum can be fitted with an absorbed powerlaw model, with NH fixed at the Galactic value of 7.13 x 10^20 cm^-2 and a photon index of 1.8 (-0.9/+1.0). The unabsorbed average 0.5-4 keV flux is estimated to be 5.8 (-2.2/+3.3) x 10^-11 erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/39387. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37397] Konus-Wind detection of GRB 250217C (short)
by GCN Circulars 20 Feb '25

20 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39386 SUBJECT: Konus-Wind detection of GRB 250217C (short) DATE: 25/02/20 14:18:00 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The short-duration GRB 250217C (Fermi-GBM detection: The Fermi GBM team, GCN 39357; Smith, GCN 39367; AstroSat-CZTI detection: Tembhurnikar et al., GCN 39359; IPN triangulation: Kozyrev et al., GCN 39365; SVOM-GRM detection: Wang et al., GCN 39369) triggered Konus-Wind at T0=86086.280 s UT (23:54:46.280). The burst light curve shows a multipeaked structure which starts at ~T0 and has a total duration of ~0.3 s. The emission is seen up to ~4 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250217_T86086/ As observed by Konus-Wind, the burst had a fluence of 2.76(-0.35,+0.38)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.190 s, of 2.38(-0.47,+0.49)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 4 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.27(-0.49,+0.70), the high energy photon index beta = -1.93(-0.11,+0.09), the peak energy Ep = 116(-26,+40) keV (chi2 = 47/37 dof). All the quoted errors are at the 68% confidence level. All the quoted values are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/39386. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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