Polar-structure galaxies beyond the local Universe: first results from Euclid

Overview & Synopsis

Galaxies hosting strongly misaligned stellar and gas structures offer a direct window into external accretion and the buildup of angular momentum through multiple spin components. Such polar-structure systems are intrinsically rare and, until now, have been identified almost entirely at low redshift. The Euclid Quick Data Release (Q1), with its uniform, space-based VIS imaging, provides an unprecedented opportunity to locate these objects over wide areas and at much greater distances. We present the first visual search for polar-structure galaxy (PSG) candidates in Euclid VIS data, spanning approximately 10% of the Q1 survey footprint. This search yields the largest high-redshift PSG candidate sample assembled to date, including roughly 100 high-confidence systems with over 50 at $z \gtrsim 0.3$, along with additional populations of face-on rings and polar tidal structures (PTS). Robust candidates are detected out to redshifts of $z\sim1$, demonstrating that polar structures can be identified well beyond the local Universe. Although the present sample is not yet sufficient for quantitative occurrence rate or evolutionary measurements, it enables initial classification and basic structural characterization of PSGs at intermediate redshift. These results lay the groundwork for future statistical studies with forthcoming Euclid data releases and illustrate Euclid's power for rare-object science across cosmic time.