2001/01/25 by David Martínez‐Delgado, D. Martinez-Delgado, J. Alonso-Garcia +4 · 9 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Dwarf galaxy #Galactic halo #Galactic tide #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Milky Way #Physics #Population #Satellite galaxy #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/319150
13 pages, 3 figures, accepted for publication in Astrophysical Journal Letters
arxiv created 2001/01/25 · openalex publication_date 2001/03/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report the detection of main-sequence and blue horizontal-branch stars of the Ursa Minor dwarf spheroidal galaxy beyond its tidal radius, indicating the existence of a possible tidal extension in this satellite of the Milky Way. This tidal extension could spread out well beyond the area covered in our survey ( R > 80'), as suggested by the presence of a "break" to a shallower slope observed in its density profile. The V -band surface brightness for this possible tidal extension ranges from 29.8 to 31.5 mag arcsec -2 . The area covered in our survey (~1.65 deg 2 ) is not enough to discriminate if this extratidal population is part of a tidal tail or an extended halo around the galaxy. The existence of this tidal extension in Ursa Minor indicates that this satellite is currently undergoing a tidal disruption process by the Milky Way. We discuss the possibility of a tidal origin for the high mass-to-light ratio observed in this galaxy on the basis of our result and recent theoretical simulations of the tidal disruption of dwarf satellites in the Galactic halo.