The Arecibo Galaxy Environment Survey VIII : Discovery of an Isolated Dwarf Galaxy in the Local Volume

Abstract

The Arecibo Galaxy Environment Survey (AGES) has detected a nearby HI source at a heliocentric velocity of +363 km/s . The object was detected through its neutral hydrogen emission and has an obvious possible optical counterpart in Sloan Digital Sky Survey (SDSS) data (though it does not have an optical redshift measurement). We discuss three possible scenarios for the object : 1) It is within the Local Group, in which case its HI properties are comparable with recently discovered ultra-compact high velocity clouds; 2) It is just behind the Local Group, in which case its optical characteristics are similar to the newly discovered Leo P galaxy; 3) It is a blue compact dwarf galaxy within the local volume but not associated with the Local Group. We find the third possibility to be the most likely, based on distance estimates from the Tully-Fisher relation and its velocity relative to the Local Group.

5 pages, 6 figures, accepted for publication in MNRAS. Minor correction to institution and address

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• The Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem
• SFI++ I: A New I-band Tully-Fisher Template, the Cluster Peculiar Velocity Dispersion and H0
• A Catalog of Ultra-compact High Velocity Clouds from the ALFALFA Survey: Local Group Galaxy Candidates?
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Cited by in corpus (3)

• NIBLES - an HI census of stellar mass selected SDSS galaxies: I. The Nançay HI survey
• The Arecibo Galaxy Environment Survey VII : A Dense Filament With Extremely Long HI Streams
• The Arecibo Galaxy Environment Survey XII : Optically dark HI clouds in the Leo I Group