1999/01/27 by L. M. Young · 6 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/300820
20 pages, 7 figures; to appear in the Astronomical Journal
arxiv created 1999/01/27 · openalex publication_date 1999/04/01 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/31
Previous searches for H I in our Galaxy's dwarf spheroidal companions have not been complete enough to settle the question of whether or not these galaxies have H I, especially in their outer parts. We present VLA observations of three dwarf spheroidals: Fornax, Leo II, and Draco, all of which have known stellar velocities. The new data show no H I emission or absorption. Column density limits in emission are 4 × 10 18 to 7 × 10 18 cm -2 in the centers of the galaxies. The importance of the new observations is that they cover larger areas than previous searches and are less plagued by confusion with foreground (Galactic) H I. The apparent absence of neutral gas in the Fornax dwarf spheroidal is especially puzzling, because recent photometry shows evidence of stars only 10 8 years old. We discuss whether the VLA observations could have missed significant amounts of H I.