TITLE: GCN CIRCULAR NUMBER: 39626 SUBJECT: EP250308a: FTW optical and NIR upper limits DATE: 25/03/09 05:35:45 GMT FROM: Brendan O'Connor at Carnegie Mellon University boconno2@andrew.cmu.edu

Malte Busmann (LMU), Brendan O’Connor (Carnegie Mellon U.), Daniel Gruen (LMU) and Antonella Palmese (Carnegie Mellon U.) report:

We observed the 90% of EP-WXT trigger 01709132392, corresponding to EP250308a, with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the r, i and J band simultaneously for 19 x 180 s starting at 2025-03-09T03:27:28 UT (0.43 days after the trigger). We performed difference imaging in the i-band with templates from Legacy Survey and detect no new or changing source.

The 3 sigma mean depth of our observations are:

r > 24.0 AB mag i > 23.8 AB mag

The magnitudes are calibrated against the PS1 catalog and not corrected for Galactic extinction.

We thank Michael Schmidt from the Wendelstein Observatory staff for obtaining these observations.

View this GCN Circular online at https://gcn.nasa.gov/circulars/39626. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...