TITLE:   GCN CIRCULAR
NUMBER:  46000
SUBJECT: EP261015a:  Wendelstein 43 cm optical observations
DATE:    26/10/20 18:26:49 GMT
FROM:    surya.shivaprasad@physik.lmu.de

Surya Shivaprasad (LMU), Malte Busmann (LMU), Brendan O'Connor (CMU), Daniel Gruen (LMU), Julius Gassert (LMU), Xander J. Hall (CMU), and Antonella Palmese (CMU) report:

We observed the counterpart of EP261015a (Corcoran et al., GCNs 45955 and 45972; Li et al., GCNs 45956 and 45969; Moreno Méndez et al., GCN 45960; Ma et al., GCN 45963; Mohan et al., GCN 45967; Fortin et al., GCN 45991; Volnova et al., GCN 45997; Pawar et al., GCN 45998) with the 43 cm telescope at Wendelstein Observatory. Observations were taken in the r band, with 47 × 300 s exposures starting at 2026-10-19T22:15:03 UT (4.37 days after the trigger). Using a template from the DESI Legacy Surveys for difference imaging, we measure an r-band magnitude of

r = 22.52 ± 0.28 AB mag.

This measurement is consistent with the updated report by Fortin et al. (GCN 45991), which reports r = 22.58 ± 0.09 AB mag at ~3.7 d post-trigger, indicating that the source is evolving slowly at this phase.

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