TITLE:   GCN CIRCULAR
NUMBER:  30937
SUBJECT: IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
DATE:    21/10/13 17:43:00 GMT
FROM:    Felicia Krauss at Penn State U  <Felicia.Krauss@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 Nuclear Spectroscopic Telescope Array (NuSTAR) has observed the 
JCMT/SCUBA2 source NVSS J040205-042434, proposed as a possible 
counterpart to the IceCube-210922A high-energy neutrino (GCN Circ. 
30862, 30882).
NuSTAR observed the position October 10 (13:55:13 UTC) -  October 11  
(17:20:00 UTC) for a total of 49.2 ksec.

No X-ray source is visible in the field of view. The 3 sigma upper limit 
for the 3-70 keV flux is 1.6x10^-11 ergs/cm^2/s assuming a photon index 
of 2.