GCN Circular 32057

Subject

Konus-Wind detection of GRB 220506A

Event

GRB 220506A

Date

2022-05-17T14:27:08Z (4 years ago)

From

Dmitry Svinkin at Ioffe Institute <svinkin@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 long-duration GRB 220506A
(MAXI/GSC detection: Urabe et al., GCN Circ. 32001Loading...
 
 )
was detected by Konus-Wind (KW) in the waiting mode.

A Bayesian block analysis of the KW waiting mode data in
the 20-1500 keV band reveals a ~6 sigma count rate increase
over background in the interval from ~T0-115 s to ~T0-89 s,
where T0 = T0(MAXI) = 23295 s UT (06:28:15).

The K-W light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB220506A/

As observed by Konus-Wind, the burst had a fluence of
1.46(-0.10,+1.13)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0-112 s, of 1.14(-0.28,+0.92)x10^-7 erg/cm2/s
(both in the 20 - 1500 keV energy range).

Modeling the K-W 3-channel time-integrated spectrum
(from ~T0-115 s to ~T0-89 s)
by a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha > -1.0 and Ep = 110(-16,+70) keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.