GRB 200313B
GCN Circular 27379
Subject
GRB 200313B: Fermi GBM Final Real-time Localization
Date
2020-03-13T11:07:35Z (5 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 10:57:12 UT on 13 Mar 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200313B (trigger 605789837.130132 / 200313456).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 202.2, Dec = 40.5 (J2000 degrees, equivalent to J2000 13h 28m, 40d 30'), with a statistical uncertainty of 5.3 degrees.
The angle from the Fermi LAT boresight is 96.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200313456/quicklook/glg_skymap_all_bn200313456.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200313456/quicklook/glg_healpix_all_bn200313456.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200313456/quicklook/glg_lc_medres34_bn200313456.gif
GCN Circular 27386
Subject
IPN triangulation of GRB 200313B (short)
Date
2020-03-15T17:21:19Z (5 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Ridnaia,
and T. Cline on behalf of the Konus-Wind team,
K. Hurley, on behalf of the IPN, and
A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
on behalf of the Fermi GBM team, report:
The short-duration GRB 200313B
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 27379)
has been detected by Fermi (GBM trigger 605789837) and Konus-Wind, so
far, at about 39432 s UT (10:57:12).
We have triangulated it to a Konus-GBM annulus centered at
RA(2000)=154.610 deg (10h 18m 26s) Dec(2000)=+8.761 deg (+8d 45' 41"),
whose radius is 60.602 +/- 2.419 deg (3 sigma).
The IPN localization is consistent with, but reduces the area of, the
Fermi-GBM one.
This localization may be improved.
A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB200313_T39435/IPN/
GCN Circular 27407
Subject
Konus-Wind observation of GRB 200313B
Date
2020-03-18T13:30:13Z (5 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:
The short-duration GRB 200313B
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 27379;
IPN triangulation: Svinkin et al., GCN Circ. 27386)
triggered Konus-Wind at T0=39435.021 s UT (10:57:15.021).
The burst light curve shows a single pulse
which starts at ~T0-0.5 s and has a total duration of ~1.4 s.
The emission is seen up to ~1 MeV.
As observed by Konus-Wind, the burst
had a fluence of 6.83(-2.07,+3.49)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.016 s,
of 1.90(-1.18,+1.53)x10^-6 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 - 1 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.71(-0.91,+1.65)
and Ep = 145(-55,+252) keV (chi2 = 31/26 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.8
(chi2 = 31/25 dof).
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB200313_T39435/
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.