Rotational Dynamics and Star Formation in the Nearby Dwarf Galaxy NGC 5238
| Autor: | Andrew McNichols, Masao Miazzo, Quinton Singer, Brian A. Eisner, Catherine Ball, Kathleen Fitzgibbon, Yaron Teich, Bridget Reilly, Asra Nizami, Elizabeth Ruvolo, John M. Cannon, Annika Brock, John Banovetz |
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| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Star formation Continuum (design consultancy) FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Astrophysics - Astrophysics of Galaxies Galaxy Interstellar medium Stars Star cluster Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Stellar evolution Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences Dwarf galaxy |
| Popis: | We present new HI spectral line images of the nearby low-mass galaxy NGC 5238, acquired with the Karl G. Jansky Very Large Array (VLA). Located at a distance of 4.51+/-0.04 Mpc, NGC 5238 is an actively star-forming galaxy with widespread H-alpha and UV continuum emission. The source is included in many ongoing and recent nearby galaxy surveys, but until this work the spatially resolved qualities of its neutral interstellar medium have remained unstudied. Our HI images resolve the disk on physical scales of ~400 pc, allowing us to undertake a detailed comparative study of the gaseous and stellar components. The HI disk is asymmetric in the outer regions, and the areas of high HI mass surface density display a crescent-shaped morphology that is slightly offset from the center of the stellar populations. The HI column density exceeds 10^21 cm^-2 in much of the disk. We quantify the degree of co-spatiality of dense HI gas and sites of ongoing star formation as traced by far-UV and H-alpha emission. The neutral gas kinematics are complex; using a spatially-resolved position-velocity analysis, we infer a rotational velocity of 31+/-5 km/s. We place NGC 5238 on the baryonic Tully-Fisher relation and contextualize the system amongst other low-mass galaxies. Accepted for publication in the Astronomical Journal |
| Databáze: | OpenAIRE |
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