GCN Circular 41059
Subject
GRB 250702B,D,E / EP250702a: ALMA detection
Event
Date
2025-07-10T18:59:43Z (2 months ago)
From
Kate D. Alexander at University of Arizona <katedenhamalexander@gmail.com>
Via
Web form
Kate D. Alexander (U of Arizona), James Miller-Jones (Curtin U), Adelle Goodwin, (Curtin U), Noah Franz (U of Arizona), Raffaella Margutti (UC Berkeley) Ryan Chornock (UC Berkeley), Dheeraj Pasham (Eureka Scientific/George Washington), Edo Berger (Harvard), Yvette Cendes (U of Oregon), and Collin Christy (U of Arizona) report on behalf of a larger collaboration:
We observed the location of the unusual transient GRB 250702B,D,E / EP250702a (GCNs 40906, 40883, 40885, 40886, 40890, 40891) with the Atacama Large Millimeter/submillimeter Array (ALMA) at multiple frequencies (program 2023.1.01731.T, PI: Miller-Jones). On 2025 July 9 02:09:03 UT, 6.97 days after the first detection with the Einstein Probe (GCN 40906) and 6.51 days after the first Fermi trigger (GCN 40883), we clearly detected the source at a mean frequency of 97.5 GHz with a preliminary flux density of ~2 mJy. Further ALMA observations are planned.
We thank the ALMA staff for quickly scheduling these observations and for providing the quick-look reduction.