Journal article
ALFALFA DISCOVERY OF THE NEARBY GAS-RICH DWARF GALAXY LEO P. V. NEUTRAL GAS DYNAMICS AND KINEMATICS
The Astronomical journal, Vol.148(2), pp.1-16
08/01/2014
DOI: 10.1088/0004-6256/148/2/35
Abstract
We present new H I spectral line imaging of the extremely metal-poor, star-forming dwarf irregular galaxy Leo P. Our H I images probe the global neutral gas properties and the local conditions of the interstellar medium (ISM). The Hi morphology is slightly elongated along the optical major axis. We do not find obvious signatures of interaction or infalling gas at large spatial scales. The neutral gas disk shows obvious rotation, although the velocity dispersion is comparable to the rotation velocity. The rotation amplitude is estimated to be V-c = 15 +/- 5 km s(-1). Within the H I radius probed by these observations, the mass ratio of gas to stars is roughly 2:1, while the ratio of the total mass to the baryonic mass is greater than or similar to 15:1. We use this information to place Leo P on the baryonic Tully-Fisher relation, testing the baryonic content of cosmic structures in a sparsely populated portion of parameter space that has hitherto been occupied primarily by dwarf spheroidal galaxies. We detect the signature of two temperature components in the neutral ISM of Leo P; the cold and warm components have characteristic velocity widths of 4.2 +/- 0.9 km s(-1) and 10.1 +/- 1.2 km s(-1), corresponding to kinetic temperature upper limits of similar to 1100 K and similar to 6200 K, respectively. The cold H I component is unresolved at a physical resolution of 200 pc. The highest Hi surface densities are observed in close physical proximity to the single H II region. A comparison of the neutral gas properties of Leo P with other extremely metal-deficient (XMD) galaxies reveals that Leo P has the lowest neutral gas mass of any known XMD, and that the dynamical mass of Leo P is more than two orders of magnitude smaller than any known XMD with comparable metallicity.
Details
- Title: Subtitle
- ALFALFA DISCOVERY OF THE NEARBY GAS-RICH DWARF GALAXY LEO P. V. NEUTRAL GAS DYNAMICS AND KINEMATICS
- Creators
- Elijah Z. Bernstein-Cooper - University of Wisconsin–MadisonJohn M. Cannon - Macalester CollegeEdward C. Elson - University of Cape TownSteven R. Warren - University of Maryland, College ParkJayaram Chengular - National Centre for Radio AstrophysicsEvan D. Skillman - University of MinnesotaElizabeth A. K. Adams - Netherlands Institute for Radio AstronomyAlberto D. Bolatto - University of Maryland, College ParkRiccardo Giovanelli - Cornell UniversityMartha P. Haynes - Cornell UniversityKristen B. W. McQuinn - University of MinnesotaStephen A. Pardy - Macalester CollegeKatherine L. Rhode - Indiana University BloomingtonJohn J. Salzer - Indiana University Bloomington
- Resource Type
- Journal article
- Publication Details
- The Astronomical journal, Vol.148(2), pp.1-16
- Publisher
- Iop Publishing Ltd
- DOI
- 10.1088/0004-6256/148/2/35
- ISSN
- 0004-6256
- eISSN
- 1538-3881
- Number of pages
- 16
- Grant note
- AST-0847109 / NSF Faculty Early Career Development (CAREER); National Science Foundation (NSF) 1211683 / Division Of Astronomical Sciences; National Science Foundation (NSF); NSF - Directorate for Mathematical & Physical Sciences (MPS) 1211683; AST-0724918; AST-0725267; AST-0725380; AST-0902211; AST0903394; AST-0607007; AST-1107390 / NSF; National Science Foundation (NSF) Brinson Foundation NSF predoctoral fellowship; National Science Foundation (NSF)
- Language
- English
- Date published
- 08/01/2014
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984627234502771
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