August 2021 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 28612]Swift GRB210825.29: Global MASTER-Net observations report
by GCN Circulars 25 Aug '21

25 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30715 SUBJECT: Swift GRB210825.29: Global MASTER-Net observations report DATE: 21/08/25 17:08:40 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB210825.29 (trigger No 1070298,15h 55m 20.62s , -54d 04m 12.7s, R=0.05) errorbox 36143 sec after notice time and 36165 sec after trigger time at 2021-08-25 16:56:13 UT, with upper limit up to 16.9 mag. Observations started at twilight. The observations began at zenith distance = 23 deg. The sun altitude is -8.8 deg. The galactic latitude b = -1 deg., longitude l = 328 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1699842 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 36256 | MASTER-SAAO | C | 180 | 16.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited.

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[vsnet-grb-info 28611]GRB 210822A: TSHAO continued optical observation
by GCN Circulars 25 Aug '21

25 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30714 SUBJECT: GRB 210822A: TSHAO continued optical observation DATE: 21/08/25 16:34:52 GMT FROM: Alexei Pozanenko at IKI, Moscow <apozanen(a)iki.rssi.ru> S. Belkin (IKI), A. Kusakin (FAP), I. Reva (FAP), Pozanenko (IKI), N. Pankov (HSE), V. Kim (FAP) report on behalf of GRB-IKI-FuN: We continue observations of GRB 210822A (Page et al., GCN 30677; Wang et al., GCN 30678; Prasad et al., GCN 30693; Frederiks et al., GCN 30694) with Zeiss-1000 telescope of Tien Shan Astronomical Observatory. on Aug. 22 (UT) 15:48:55 -- 18:48:47. We obtained series in R-filter starting on 2021-08-24 (UT) 16:47:35. The optical afterglow (Page et al., GCN 30677; Zheng et al., GCN 30679; Butler et al., GCN 30680; Fu et al., GCN 30684; Zhu et al., GCN 30692; Romanov et al., GCN 30701; Guelbenzu et al., GCN 30703; Siegel et al., GCN 30710; Belkin et al., GCN 30712) at the redshift of z = 1.736 (Zhu et al., GCN 30692) is detected in stacked image. Preliminary photometry of the afterglow in a stacked image is following. Date UT start t-T0 Filter Exp. OT Err. UL(3 sigma) (mid, days) (s) 2021-08-24 16:47:35 2.33041 R 3180 21.60 0.26 22.0 The photometry is based on nearby USNO-B1.0 stars. USNO-B1.0 RA Dec R2 20:18:06.64416 +05:17:24.1404 12.33 20:17:59.55288 +05:18:19.5912 13.05

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[vsnet-grb-info 28610]GRB 210822A: VLA detection
by GCN Circulars 25 Aug '21

25 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30713 SUBJECT: GRB 210822A: VLA detection DATE: 21/08/25 14:47:06 GMT FROM: Tanmoy Laskar at U of Bath <tanmoylaskar(a)gmail.com> T. Laskar (University of Bath), K. D. Alexander (Northwestern), E. Berger (Harvard), R. Chornock (UC Berkeley), W. Fong (Northwestern), R. Margutti (UC Berkeley), C. G. Mundell (University of Bath), P. Schady (University of Bath), and G. Schroeder (Northwestern) report on behalf of a larger collaboration: "We observed GRB 210822A (Page et al. GCN 30677) with the Karl G. Jansky Very Large Array (VLA) beginning on 2021 August 24 at 05:30 UT (1.9 d after the burst). At a mean frequency of 14.8 GHz, we detect a radio source with a preliminary flux density of ~ 0.4 mJy at the position: RA (J2000) = 20:17:44.992 +/- 0.001 Dec (J2000) = 05:16:59.53 +/- 0.02 consistent with the position of the optical afterglow (Page et al., GCN 30677) and the Swift/XRT afterglow (Evans al., GCN 30682). Follow-up observations are planned. We thank the VLA staff for rapidly executing these observations."

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[vsnet-grb-info 28609]GRB 210822A: TSHAO optical observation
by GCN Circulars 25 Aug '21

25 Aug '21

TITLE: GCN CIRCULAR NUMBER: 30712 SUBJECT: GRB 210822A: TSHAO optical observation DATE: 21/08/25 09:49:39 GMT FROM: Alexei Pozanenko at IKI, Moscow <apozanen(a)iki.rssi.ru> S. Belkin (IKI), A. Kusakin (FAP), I. Reva (FAP), Pozanenko (IKI), N. Pankov (HSE), V. Kim (FAP) report on behalf of GRB-IKI-FuN: We observed GRB 210822A (Page et al., GCN 30677; Wang et al., GCN 30678; Prasad et al., GCN 30693; Frederiks et al., GCN 30694) with Zeiss-1000 telescope of Tien Shan Astronomical Observatory on Aug. 22 (UT) 15:48:55 -- 18:48:47. We obtained series with 20 and 30 sec exposition in R-filter. The optical afterglow (Page et al., GCN 30677; Zheng et al., GCN 30679; Butler et al., GCN 30680; Fu et al., GCN 30684; Zhu et al., GCN 30692; Romanov et al., GCN 30701; Guelbenzu et al., GCN 30703; Siegel et al., GCN 30710) at redshift z = 1.736 (Zhu et al., GCN 30692) is detected in stacked images. Preliminary photometry of the afterglow in a stacked image of the second series is following. Date UT start t-T0 Filter Exp. OT Err. UL(3 sigma) (mid, days) (s) 2021-08-22 17:26:41 0.36184 R 196*20 18.63 0.03 21.0 The photometry is based on nearby USNO-B1.0 stars. USNO-B1.0 RA Dec R2 20:18:06.64416 +05:17:24.1404 12.33 20:17:59.55288 +05:18:19.5912 13.05

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