TITLE:   GCN CIRCULAR
NUMBER:  42744
SUBJECT: GRB 251117A: FTW Observations of Swift candidate X-ray sources
DATE:    25/11/18 20:56:30 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 candidate Swift X-ray sources GRB 251117a_X6 and X7 (Evans et al., GCN 42730), as potential counterparts to GRB 251117A (Fermi GBM team, GCN 42719; Airasca et al., GCN 42729; Wang et al., GCN 42731; DeLaunay et al., GCN 42732; Arya et al., GCN 42740) with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the r, i and J band simultaneously for 10 x 180 s starting at 2025-11-18T17:36:17 UT (1.22 days after the trigger). 

We performed difference imaging with archival images from Legacy Survey and do not detect any new sources down to

r > 23.9 AB mag (3 sigma).

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

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