TITLE: GCN CIRCULAR NUMBER: 42814 SUBJECT: GRB 251122A/EP251122a: FTW optical and NIR observations DATE: 25/11/23 22:37:25 GMT FROM: Malte Busmann at Ludwig-Maximilians-Universität München m.busmann@physik.lmu.de

Malte Busmann (LMU), Xander J. Hall (CMU), Brendan O’Connor (CMU), Daniel Gruen (LMU), and Antonella Palmese (CMU) report:

We observed the FXT localization of GRB 251122A/EP251122a (Wang et al., GCN 42779; Lin et al., GCN 42800; Yin et al., GCN 42808; Wang et al., GCN 42809) with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the r, i, and J bands simultaneously for 40 x 180 s starting at 2025-11-23T00:06:12 UT (0.43 days after the trigger). We used r-band templates from the DESI Legacy Survey for difference imaging and did not detect the source identified by Cheng et al. (GCN 42803), Li et al. (GCN 42806), Sun et al. (GCN 42807), Ma et al. (GCN 42811), and Gupta et al. (GCN 42813) at a 3-sigma depth of

r > 24 AB mag.

The magnitude is calibrated against the PS1 catalog and not corrected for Galactic extinction.

We thank Christoph Ries from the Wendelstein Observatory for obtaining these observations.

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