GCN Circular 44403
Subject
EP260321a: Upper limits from ATCA radio observations
Event
Date
2026-04-23T17:14:05Z (2 days ago)
From
Nayana A J at University of California, Berkeley <nayan89deva@gmail.com>
Via
Web form
Nayana A.J., Eli Wiston, Raffaella Margutti, Itai Sfaradi, Ryan Chornock (UC Berkeley) report:
We observed the field of EP260321a (Huang et al., GCN 44068) with the Australia Telescope Compact Array (ATCA) using the BIGCAT system. The observations were conducted on 2026 March 30.37 UT in the 15 mm band, utilizing a total instantaneous bandwidth of approximately 8 GHz, divided into four 2 GHz-wide sub-bands, each imaged independently. The resulting images have central observing frequencies of 17, 19, 21, and 23 GHz. In our preliminary analysis, we do not detect radio emission at the position of the optical counterpart (Lee et al., GCN 44070; Tanvir et al., GCN 44082). The corresponding 3-sigma flux density upper limits are 0.21, 0.15, 0.075, and 0.06 mJy at 17, 19, 21, and 23 GHz, respectively.
We thank the ATCA operations staff for their prompt scheduling of these observations. The Australia Telescope Compact Array is part of the Australia Telescope National Facility, funded by the Australian Government for operation as a National Facility managed by CSIRO.