We present the first stellar stream discovered with the Vera C. Rubin Observatory, around spiral galaxy M61 (NGC 4303) in Virgo First Look imaging. The stream is narrow, radially-oriented in projection, and ~50 kpc long. It has g-band surface brightness (SB) mu_g ~ 28 AB mag arcsec^-2, color g-z ~ 1.0, and stellar mass M_* ~ 2x10^8 M_Sun. This dwarf galaxy interaction may have provoked the M61 starburst, and foreshadows the bounty of accretion features expected in the ten-year Rubin Legacy Survey of Space and Time (LSST).
@article{arxiv.2510.24836,
title = {A stellar stream around the spiral galaxy Messier 61 in Rubin First Look imaging},
author = {Aaron J. Romanowsky and David Martínez-Delgado and Giuseppe Donatiello and Juan Miró-Carretero and Seppo Laine},
journal= {arXiv preprint arXiv:2510.24836},
year = {2025}
}