Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. See news and announcements

GCN Circular 41597

Subject
EP250821a: SOAR observations
Event
EP250821a
Date
2025-08-29T19:29:04Z (a month ago)
From
James Freeburn at University of North Carolina at Chapel Hill <jamesfreeburn54@gmail.com>
Via
Web form
J. Freeburn (UNC), G. Srinivasaragavan (UMD), I. Andreoni (UNC), Anna Ho (Cornell)

We observed the location of the X-ray transient, EP250821a (Hu et al., GCN 41459) with the Goodman High Throughput Spectrograph mounted on the SOAR telescope in imaging mode (PI: Andreoni). We took two 300s exposures each in g, r and i-band between 2025-08-29T01:15:29 and 2025-08-29T01:43:27 UTC corresponding to ~8 days after the initial trigger.

With image subtraction using Legacy Survey images (Dey et al., 2019), we do not detect the optical counterpart associated with EP250821a (Dichiara et al., GCN 41469; Li et al., GCN 41470; Yao et al., GCN 41485; Oates et al., GCN 41491) and place the following 5-sigma AB magnitude upper limits:

g > 22.9
r > 22.9
i > 22.8
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov