The outer disc in shambles: Blind detection of Monoceros and the ACS with <i>Gaia</i>’s astrometric sample

Context. The Gaia astrometric sample allows us to study the outermost Galactic disc, halo, and their interface. It is precisely at very edge of disc where effects external perturbations are expected be most noticeable. Aims. Our goal detect kinematic substructure present in halo Milky Way (MW) provide observational constraints on phase-space distribution. Methods. We download, one HEALpix a time, proper motion histogram distant stars, which we apply wavelet transformation reveal significant overdensities. then analyse large coherent structures that appear sky. Results. sharp yet complex anticentre dominated by Monoceros (MNC) Anticentre Stream (ACS) north – find have intensities comparable Magellanic Clouds Sagittarius stream MNC South TriAnd negative latitudes. method perform morphological analysis ACS, both span more than 100° longitude, high purity giants with track down latitudes as low ?5°. Their colour-magnitude diagram consistent extended distance ?10?11 kpc originated ratio RR Lyrae over M giants, kinematics compatible rotation curve those distances or slightly slower. Conclusions. precise characterisation two previously known our reveals naturally, allowing them without limiting ourselves particular stellar type and, for first using only kinematics. results will allow future studies model chemo-dynamics evolution, thus constraining some influential processes shaped MW.