[vsnet-grb-info 27035] Swift Trigger 1014012 (possible GRB 201221C) is likely not an astrophysical event

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29138
SUBJECT: Swift Trigger 1014012 (possible GRB 201221C) is likely not an astrophysical event
DATE:    20/12/22 17:42:53 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien at nasa.gov>

S. D. Barthelmy (GSFC), A. Y. Lien (GSFC/UMBC) and K. L. Page (U Leicester)
report on behalf of the Neil Gehrels Swift Observatory Team:

Using the full data set from recent downlinks, we report further ground
data analysis for Swift trigger 1014012 (Page et al. GCN Circ. 29106).

The BAT analysis uses data from T-239 to T+963 sec. The BAT image
significance has now decreased to 5.2 sigma (15-350 keV). Also, the
mask-weighted light curve does not show anything significant.

There is no good evidence for an X-ray source in 4.7 ks data, to a 3 sigma
upper limit of 2.3x10^-3 count s^-1 (corresponding to an observed flux of
1x10^-13 erg cm^-2 s^-1, assuming a typical power-law spectrum).

We therefore conclude that this event is likely due to noise,
and is not an astrophysical event.