TITLE: GCN CIRCULAR NUMBER: 40979 SUBJECT: Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array DATE: 25/07/05 16:16:46 GMT FROM: Itai Sfaradi at University of California, Berkeley <itai.sfaradi@mail.huji.ac.il> Authors: I. Sfaradi (UC Berkeley), R. Margutti (UC Berkeley), W. Farah (SETI Institute, UC Berkeley), S. Sheikh (SETI Institute, UC Berkeley), R. Chornock (UC Berkeley), V. Garcia Lopez (SETI Institute), J. Bright (Oxford), K. Alexander (University of Arizona), A. Siemion (Oxford, SETI Institute), A. Pollak (SETI Institute), Y. Yao (UC Berkeley), Nayana A.J. (UC Berkeley), H. Sears (Rutgers U) We observed the field of the Einstein Probe source EP250702a (GCN 40906) with the Allen Telescope Array (ATA) on July 4, 2025, between 04:25:12 to 10:48:50 (UTC) about 2 days after first discovery. Our observation was carried out with four spectral windows centered around 1.5 and 3, 5, and 8 GHz, each with a bandwidth of 672 MHz. Calibration and imaging were performed using CASA with 3C286 as a bandpass and absolute flux scale calibrator, and 1822-096 as a complex gain calibrator. No radio emission was detected at the position of EP250702a and we report here a flux density upper limit (3 sigma image RMS) of 1.1 mJy/beam in 5 GHz. For comparison, while the distance of this EP source is not known, we note that the level of emission in GRB 221009A was ~18 mJy at 5 GHz, ~2 days after discovery (Bright et al. 2023). The Allen Telescope Array refurbishment program and its ongoing operations are being substantially funded through the Franklin Antonio Bequest. Additional contributions from Frank Levinson, Greg Papadopoulos, the Breakthrough Listen Initiative and other private donors have been instrumental in the renewal of the ATA. Breakthrough Listen is managed by the Breakthrough Initiatives, sponsored by the Breakthrough Prize Foundation. The Paul G. Allen Family Foundation provided major support for the design and construction of the ATA, alongside contributions from Nathan Myhrvold, Xilinx Corporation, Sun Microsystems, and other private donors. The ATA has also been supported by contributions from the US Naval Observatory and the US National Science Foundation. View this GCN Circular online at https://gcn.nasa.gov/circulars/40979. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...