Euclid Quick Data Release (Q1) The first catalogue of strong-lensing galaxy clusters

We present the first catalogue of strong lensing galaxy clusters identified in the Euclid quick release 1 observations (∼ 53 deg2 ). This catalogue is the result of the visual inspection of 1260 cluster fields, primarily identified by Wen & Han (2024). Specifically, we identified 84 gravitational lenses with a probability larger than 0.5, of which 14 with a probability of 1, and clearly exhibiting secure strong lensing features, such as giant tangential and radial arcs, and multiple images. We forecast that Euclid will discover ∼6000 secure cluster-scale lenses over the course of its full survey. The identified strong lensing features will be crucial for training sophisticated deep learning models for identifying gravitational arcs and multiple images automatically in Euclid observations. This study confirms the huge potential of Euclid for finding new strong lensing clusters, enabling exciting new discoveries on the nature of dark matter and dark energy and the study of the high-redshift Universe. Key words. Galaxies: clusters: general – Gravitational lensing: strong – cosmology: observations – dark matter