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.