GCN Circular 44981
Subject
GRB 260610B/AT 2026owq: FTW optical and NIR observations
Event
Date
2026-06-18T19:32:02Z (15 days ago)
From
Julius Gassert at Ludwig-Maximilians-Universität München <julius.gassert@campus.lmu.de>
Via
Web form
Julius Gassert (LMU/CMU), Malte Busmann (LMU), Brendan O'Connor (CMU), Daniel Gruen (LMU), Xander Hall (CMU), and Antonella Palmese (CMU) report:
We observed the afterglow of GRB260610B (AT 2026owq) (Fermi/GBM; GCN 44901; O’Neill et al., GCNs 44903, 44914; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCNs 44911, 44930; Moskvitin et al., GCNs 44918, 44929; Jackson-Horne et al., GCN 44919; Izzo et al., GCN 44920; Li et al., GCN 44921; Bochenek et al., GCNs 44927, 44932; Pankov et al., GCN 44946), with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the g, r, i, z, and J bands for 8x 180s starting at 2026-06-17 22:48 UT.
As previously reported (Gillanders et al., GCN 44955; Angulo et al., GCN44958; Dimple et al., GCN44959; Moksvitin et al. GCN44963; Pankov et al., GCN44977), we also detect the rebrightening/flattening in all bands, althought the i-band detection is marginal.
In the r band, we detect the counterpart at:
r = 21.31 +/- 0.10 AB mag
The magnitude is calibrated against the PS1 catalog and not corrected for Galactic extinction.
We thank Silona Wilke from the Wendelstein Observatory for obtaining these observations.