GCN Circular 40281
Subject
EP250428b: LAST optical upper limit
Date
2025-04-29T21:33:20Z (a day ago)
From
Ruslan Konno at Weizmann Institute of Science <ruslankonno@gmail.com>
Via
Web form
R. Konno (WIS), S. Garrappa (WIS), E. A. Zimmerman (WIS), A. Horowicz (WIS), E. O. Ofek (WIS), S. Ben-Ami (WIS), D. Polishook (WIS), O. Yaron (WIS), S. Fainer (WIS), A. Krassilchtchikov (WIS), Y. M. Shani (WIS), E. Segre (WIS), A. Gal-Yam (WIS), S. Spitzer (WIS), and K. Rybicki (WIS) on behalf of the LAST Collaboration
We report observations of the X-ray transient EP250428b (Liu et al., GCN 40277) with the Large Array Survey Telescope (LAST, Ofek et al. 2023; Ben-Ami et al. 2023). We observe the field of EP250428b using four telescopes, each with a FoV of 7.4 deg^2 and no filter (clear - similar to the GAIA Bp band).
We began observations at 2025-04-29 18:25:34.194 UTC (T-T0 = 36.3h). We coadd a total of 160x20s exposure images and perform image subtraction using a reference image of the field. We do not detect any new optical source up to a limiting magnitude of 21.66 (AB) within the reported error regions of FXT and WXT.
LAST is a survey telescope array of the Weizmann Astrophysical Observatory (https://www.weizmann.ac.il/wao/).