2009/07/01 by Elena D'Onghia, Elena D’Onghia, Gurtina Besla +2 · 2 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Dwarf galaxy #Dwarf galaxy problem #Dwarf spheroidal galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Interacting galaxy #Local Group #Physics #Ram pressure #Star formation #Stellar, planetary, and galactic studies #astro-ph.CO
paper · pdf · doi:10.1038/nature08215
Accepted as a Letter to Nature. A press release will be issued at the time of publication
openalex publication_date 2009/07/01 · arxiv created 2009/07/15 · arxiv updated 2015/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Dwarf spheroidal galaxies are the most dark matter dominated systems in the nearby Universe and their origin is one of the outstanding puzzles of how galaxies form. Dwarf spheroidals are poor in gas and stars, making them unusually faint, and those known as ultra-faint dwarfs have by far the lowest measured stellar content of any galaxy. Previous theories require that dwarf spheroidals orbit near giant galaxies like the Milky Way, but some dwarfs have been observed in the outskirts of the Local Group. Here we report simulations of encounters between dwarf disk galaxies and somewhat larger objects. We find that the encounters excite a process, which we term ``resonant stripping'', that can transform them into dwarf spheroidals. This effect is distinct from other mechanisms proposed to form dwarf spheroidals, including mergers, galaxy-galaxy harassment, or tidal and ram pressure stripping, because it is driven by gravitational resonances. It may account for the observed properties of dwarf spheroidals in the Local Group, including their morphologies and kinematics. Resonant stripping predicts that dwarf spheroidals should form through encounters, leaving detectable long stellar streams and tails.