Stellar Velocity Dispersion of the Leo A Dwarf Galaxy

Abstract

We measure the first stellar velocity dispersion of the Leo A dwarf galaxy, σ= 9.3 +- 1.3 km/s. We derive the velocity dispersion from the radial velocities of ten young B supergiants and two HII regions in the central region of Leo A. We estimate a projected mass of 8 +- 2.7 x10^7 solar masses within a radius of 2 arcmin, and a mass to light ratio of at least 20 +- 6 M_sun/L_sun. These results imply Leo A is at least ~80% dark matter by mass.

6 pages, accepted to ApJ

References in corpus (10)

• A Faint New Milky Way Satellite in Bootes
• On Extending the Mass-Metallicity Relation of Galaxies by 2.5 Decades in Stellar Mass
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• Hypervelocity Stars: From the Galactic Center to the Halo
• Velocity Dispersion Profile of the Milky Way Halo
• Hypervelocity Stars III. The Space Density and Ejection History of Main Sequence Stars from the Galactic Center
• Chemistry and Kinematics of the Late-Forming Dwarf Irregular Galaxies Leo A, Aquarius, and Sagittarius DIG
• MMT Hypervelocity Star Survey. II. Five New Unbound Stars
• A Deficit of Dark Matter from Jeans Modeling of the Ultra-diffuse Galaxy NGC 1052-DF2
• Formation of Dwarf Spheroidal Galaxies Via Mergers of Disky Dwarfs
• An optical and HI study of the dwarf Local Group galaxy VV124=UGC4879. A gas-poor dwarf with a stellar disk?
• The Sample of Red Supergiants in Twelve Low-Mass Galaxies of the Local Group
• Solo dwarfs II: The stellar structure of isolated Local Group dwarf galaxies
• Near-Infrared Stellar Populations in the metal-poor, Dwarf irregular Galaxies Sextans A and Leo A
• Dwarf Irregular Galaxy Leo A. Suprime-Cam Wide-Field Stellar Photometry
• A Panchromatic Study of Massive Stars in the Extremely Metal-Poor Local Group Dwarf Galaxy Leo A
• Star clusters in the dwarf irregular galaxy Leo A
• Star clusters and young populations in the dwarf irregular galaxy Leo A
• The Future of Stellar Populations Studies in the Milky Way and the Local Group