Searches for HI in the Outer Parts of Four Dwarf Spheroidal Galaxies

Abstract

Previous searches for atomic gas in our Galaxy's dwarf spheroidal companions have not been complete enough to settle the question of whether or not these galaxies have HI, especially in their outer parts. We present new observations of the dwarf spheroidals Sextans, Leo I, Ursa Minor, and Draco, using the NRAO 140-foot telescope to search much farther in radius than has been done before. The new data go out to at least 2.5 times the core radius in all cases, and well beyond even the tidal radius in two cases. These observations give HI column density limits of 2-6 x 10^17 atoms cm^-2. Unless HI is quite far from the galaxies' centers, we conclude that these galaxies don't contain significant amounts of atomic gas at the present time. We discuss whether the observations could have missed some atomic gas.

To appear in A.J

Cited by in corpus (22)

• The Progenitors of Dwarf Spheroidal Galaxies
• The AMIGA project. I. Optical characterization of the CIG catalog
• The Star Formation History and the spatial distribution of stellar populations in the Ursa Minor Dwarf Spheroidal Galaxy
• The Chemical Evolution of the Ursa Minor Dwarf Spheroidal Galaxy
• MMT Hypervelocity Star Survey
• Kinematic Constraints on Evolutionary Scenarios for Blue Compact Dwarf Galaxies : I. Neutral Gas Dynamics
• Proper Motions of Dwarf Spheroidal Galaxies from Hubble Space Telescope Imaging. III: Measurement for Ursa Minor
• Life at the Periphery of the Local Group: the kinematics of the Tucana Dwarf Galaxy
• Hypervelocity Stars III. The Space Density and Ejection History of Main Sequence Stars from the Galactic Center
• HST detection of spiral structure in two Coma Cluster dwarf galaxies
• The Dwarf Spheroidal Companions to M31: WFPC2 Observations of Andromeda III
• Search for 511 keV Emission in Satellite Galaxies of the Milky Way with INTEGRAL/SPI
• A Search for Ionized Gas in the Draco and Ursa Minor Dwarf Spheroidal Galaxies
• The Gas Content and Kinematics of Nearby Blue Compact Galaxies: Implications for Studies at Intermediate and High Redshift
• On the neutral gas content of nine new Milky Way satellite galaxy candidates
• Three-dimensional hydrodynamical simulations of the supernovae-driven gas loss in the dwarf spheroidal galaxy Ursa Minor
• Foreground effect on the $J$-factor estimation of classical dwarf spheroidal galaxies
• Why Are There Dwarf Spheroidal Galaxies?
• Foreground effect on the $J$-factor estimation of ultra-faint dwarf spheroidal galaxies
• Dark Matter Subhalos in the Ursa Minor Dwarf Galaxy
• Parameterizing the Outflow from a Central Black Hole in Dwarf Spheroidal Galaxies: A 3D Hydrodynamic Simulation
• Local Group(s)