ALFALFA DISCOVERY OF THE NEARBY GAS-RICH DWARF GALAXY LEO P. II. OPTICAL IMAGING OBSERVATIONS

Abstract

We present results from ground-based optical imaging of a low-mass dwarf\ngalaxy discovered by the ALFALFA 21-cm HI survey. Broadband (BVR) data obtained\nwith the WIYN 3.5-m telescope at Kitt Peak National Observatory (KPNO) are used\nto construct color-magnitude diagrams of the galaxy's stellar population down\nto V_0 ~ 25. We also use narrowband H-alpha imaging from the KPNO 2.1-m\ntelescope to identify an HII region in the galaxy. We use these data to\nconstrain the distance to the galaxy to be between 1.5 and 2.0 Mpc. This places\nLeo P within the Local Volume but beyond the Local Group. Its properties are\nextreme: it is the lowest-mass system known that contains significant amounts\nof gas and is currently forming stars.\n