2006/11/21 by Jeremy Bailin, H. Alyson Ford, Alyson Ford · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1111/j.1745-3933.2006.00271.x
published as Mon.Not.Roy.Astron.Soc.Lett.375:L41-L45,2007 · 5 pages, MNRAS, accepted
arxiv created 2006/11/21 · openalex publication_date 2006/12/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Abstract Neutral hydrogen (H i) observations towards the Boötes dwarf spheroidal (dSph) galaxy (hereafter Boötes), a very low-luminosity metal-poor Galactic satellite, have been obtained using the Parkes Radio Telescope. We do not detect any H i in or around Boötes to a 3σ upper limit of 180 M⊙ within the optical half-light radius and 8000 M⊙ within 1.6 kpc. Its H i mass-to-light ratio is less than 0.002 M⊙/L⊙, making Boötes one of the most gas-poor galaxies known. Either reionization severely inhibited gas infall on to the proto-Boötes, or large amounts of gas have been removed by ram pressure and/or tidal stripping. Since Boötes lies on the mass–metallicity fundamental line, this relation and the inefficiency of star formation at the faintest end of the galaxy luminosity function must be partly driven, or at least not disrupted, by extreme gas loss in such low-luminosity galaxies. We also do not detect any H i associated with the leading tidal tail of the Sagittarius dSph galaxy, which fortuitously passes through the observed field, to a 3σ column density limit of 2 × 1017cm−2. This suggests that either the leading gaseous tail is ionized, or the gas in the trailing tail was removed before the current tidal disruption of the parent dSph began.