NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-26 T23:58:25 PDT
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For refcode 2017AJ....153..213I:
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Copyright by American Astronomical Society. Reproduced by permission
2017AJ....153..213I Accurate Recovery of H I Velocity Dispersion from Radio Interferometers Ianjamasimanana, R.; de Blok, W. J. G.; Heald, George H. Abstract. Gas velocity dispersion measures the amount of disordered motion of a rotating disk. Accurate estimates of this parameter are of the utmost importance because the parameter is directly linked to disk stability and star formation. A global measure of the gas velocity dispersion can be inferred from the width of the atomic hydrogen (H I) 21 cm line. We explore how several systematic effects involved in the production of H I cubes affect the estimate of H I velocity dispersion. We do so by comparing the H I velocity dispersion derived from different types of data cubes provided by The H I Nearby Galaxy Survey. We find that residual-scaled cubes best recover the H I velocity dispersion, independent of the weighting scheme used and for a large range of signal-to-noise ratio. For H I observations, where the dirty beam is substantially different from a Gaussian, the velocity dispersion values are overestimated unless the cubes are cleaned close to (e.g., ~1.5 times) the noise level. Key words: galaxies: fundamental parameters, galaxies: ISM, ISM: kinematics and dynamics, line: profiles, methods: data analysis
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