GCN Circular 31606
Subject
GRB 220211A: redshift lower limit estimating
Event
Date
2022-02-18T22:04:09Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
P. Minaev (IKI), A. Pozanenko (IKI) report on behalf of GRB IKI FuN:
We analysed GRB 220211A (The Fermi GBM team, GCN 31570; Tohuvavohu et
al., GCN 31582; Ridnaia et al., GCN 31584; Svinkin et al., GCN 31599)
using publicly available data of GBM/Fermi. We estimate the duration in
7 - 850 keV energy band T_90 = 0.11 +/- 0.02 s. We performed spectral
analysis in a time interval of (-0.05, 0.05) s, the best fit is obtained
for CPL model with following parameters: E_p = 924 (-210, +317) keV,
alpha = -0.50 +/- 0.25. The fluence of F = (5.8 +/- 0.5)E-7 erg/cm**2 is
obtained in 10 - 1000 keV energy band.
Using T_90,i - EH diagram [1,2] we classify the burst as type I (short)
and find the minimal possible redshift value of z = 0.13 and the most
probable value of the redshift z = 0.53.
The T_90,i - EH diagram can be found in
http://grb.rssi.ru/GRB220211A/GRB220211A_EHD.png
The burst could also be classified as SGR Giant flare, placed at
distance of D_L = 8.7 Mpc.
[1] - Minaev et al., MNRAS, 492, 1919, 2020
[2] - Minaev et al., Astronomy Letters, 46, 9, 573, 2020