TITLE: GCN CIRCULAR NUMBER: 42862 SUBJECT: EP251124a: Pan-STARRS ri-band imaging and photometry DATE: 25/11/27 13:50:26 GMT FROM: James Gillanders at University of Oxford <jhgillanders.astro@gmail.com> J. H. Gillanders (Oxford), M. Huber, K. C. Chambers (IfA, Univ. Hawaii), S. J. Smartt, K. W. Smith (Oxford/QUB), S. Srivastav (Oxford), M. Nicholl, D. Young, M. Fulton (QUB), T.-W. Chen (NCU, Taiwan) A. S. B. Schultz, T. de Boer, J. Fairlamb, G. Paek, C. C. Lin, T. Lowe, E. Magnier, P. Minguez, I. A. Smith, R. J. Wainscoat (IfA, Univ. Hawaii). We observed the optical counterpart of EP251124a (Zhou et al., GCN 42816), using the Pan-STARRS telescope system (Chambers et al., 2016, arXiv e-prints, 1612.05560) on MJD 61004.36 (2025-11-25 08:38:24 UTC), 0.90 days after the EP-WXT detection (Zhou et al., GCN 42816). The Pan-STARRS system consists of 2x1.8m telescope units located at the summit of Haleakala on the Hawaiian island of Maui, employing an SDSS-like filter system denoted as grizy, and a broad w filter, which is a composite of the gri filters. Our observation consisted of 6x150s exposures in both the r and i filters with Pan-STARRS1. The images were processed with the Pan-STARRS pipeline. After astrometric and photometric calibration, reference images were subtracted from the target stacked images (Magnier et al., 2020a, ApJS, 251, 3; Magnier et al., 2020b, ApJS, 251, 6; Waters et al., 2020, ApJS, 251, 4). From these difference images, we do not detect any optical counterpart down to 3.5-sigma limiting AB magnitudes of r~22.3 and i~22.3. Our upper limits are in agreement with previously reported limits from Mohan et al. (GCN 42817), Wang et al. (GCN 42824), Lipunov et al. (GCN 42828), van Hoof et al. (GCN 42829), and Ma et al. (GCN 42833). View this GCN Circular online at https://gcn.nasa.gov/circulars/42862. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...