TITLE:   GCN CIRCULAR
NUMBER:  30877
SUBJECT: IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
DATE:    21/09/24 20:52:44 GMT
FROM:    Hugo Ayala at Pennsylvania State University  <hgayala@psu.edu>

Felicia Krauss, Timothée Gregoire, Derek Fox, Doug Cowen, Hugo Ayala
(PSU) and Alexis Coleiro (APC) report for AMON (https://amon.psu.edu/):

The Neil Gehrels Swift Observatory X-ray Telescope (XRT) observed the
uncertainty region of the IceCube neutrino event IceCube-210922A (GCN
Circ. 30862) on 2021-09-23, between 02:00 and 21:52 UTC .
A 6-point tiling observation centered on the neutrino position was taken
for a total of 3.5 ksec.
Of the 90% confidence 1.23 sq. degrees uncertainty region, the XRT
observations cover roughly 75% of the central area.

No X-ray candidate counterparts were detected above a level of 3 sigma.

The 3 sigma upper limit for the flux is  1.2x10^(-13) ergs/s/cm^2.