GRB 210421C
GCN Circular 29871
Subject
GRB 210421C: Fermi GBM Final Real-time Localization
Date
2021-04-21T20:23:17Z (4 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely SHORT GRB
At 20:12:53 UT on 21 Apr 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210421C (trigger 640728778.025922 / 210421842).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 192.2, Dec = -61.9 (J2000 degrees, equivalent to J2000 12h 48m, -61d 53'), with a statistical uncertainty of 14.3 degrees.
The angle from the Fermi LAT boresight is 125.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210421842/quicklook/glg_skymap_all_bn210421842.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210421842/quicklook/glg_healpix_all_bn210421842.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210421842/quicklook/glg_lc_medres34_bn210421842.gif
GCN Circular 29873
Subject
Fermi GRB 210421C: Global MASTER-Net observations report
Date
2021-04-21T21:30:14Z (4 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@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) started inspect of the Fermi GRB 210421C ( Fermi GBM team, GCN 29871) errorbox 3606 sec after notice time and 3636 sec after trigger time at 2021-04-21 21:13:29 UT, with upper limit up to 18.8 mag. The observations began at zenith distance = 24 deg. The sun altitude is -62.3 deg.
The galactic latitude b = 1 deg., longitude l = 303 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=1598370
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
3666 | 2021-04-21 21:13:29 | MASTER-SAAO | (12h 44m 20.32s , -55d 59m 18.1s) | C | 60 | 18.5 |
3839 | 2021-04-21 21:16:21 | MASTER-SAAO | (13h 00m 06.56s , -55d 58m 20.2s) | C | 60 | 17.6 |
3918 | 2021-04-21 21:17:41 | MASTER-SAAO | (12h 35m 41.98s , -53d 57m 24.5s) | C | 60 | 18.4 |
4248 | 2021-04-21 21:23:10 | MASTER-SAAO | (12h 47m 33.26s , -53d 57m 52.4s) | C | 60 | 18.8 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.