TITLE: GCN CIRCULAR NUMBER: 36007 SUBJECT: X-ray transient EP20240331a: MeerLICHT optical upper limits DATE: 24/04/01 19:41:53 GMT FROM: Paul Groot at Radboud University Nijmegen <p.groot@astro.ru.nl> Paul Groot (Radboud/UCT/SAAO), Peter Jonker (Radboud), Andrew Levan (Radboud), Danielle Pieterse (Radboud) and Paul Vreeswijk (Radboud) report on behalf of the MeerLICHT consortium: The 0.6m MeerLICHT optical telescope, located at Sutherland, South Africa, observed the error box of EP20240331a (Pan et al.,2024, ATel #16564) using two of its predefined sky-grid tiles to cover the reported error box. Observations started on 2024-04-01 18:16UT, approximately 20 hours after the Einstein Probe detection. The telescope cycled through the u,q (440-720nm) and i-band filters on each field alternatingly using 60s integrations per exposure. Data was processed immediately through the BlackBOX/ZOGY pipeline, running at the South African Inter-university Institute for Data Intensive Astronomy (IDIA), No transient is detected in the full 20'-radius error box region with respect to the MeerLICHT reference images dating from 2020-02-24. Image-averaged 5-sigma point-source limiting magnitudes for transients were 20.4 (q-band), 18.7 (u-band) and 19.1 (i-band). Further analysis will follow. MeerLICHT is built and run by a consortium consisting of Radboud University, University of Cape Town, the South African Astronomical Observatory, the University of Oxford, the University of Manchester and the University of Amsterdam. View this GCN Circular online at https://gcn.nasa.gov/circulars/36007. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...