SHIELD: NEUTRAL GAS KINEMATICS and DYNAMICS

Andrew T. McNichols, Yaron G. Teich, Elise Nims, John M. Cannon, Elizabeth A K Adams, Riccardo Giovanelli, Martha P. Haynes, Kristen B W McQuinn, John J. Salzer, Evan D. Skillman, Elijah Z. Bernstein-Cooper, Andrew Dolphin, E. C. Elson, Nathalie Haurberg, Gyula I G Józsa, Jürgen Ott, Amelie Saintonge, Steven R. Warren, Ian Cave, Cedric HagenShan Huang, Steven Janowiecki, Melissa V. Marshall, Clara M. Thomann, Angela Van Sistine

    Research output: Contribution to journalArticle

    14 Scopus citations

    Abstract

    We present kinematic analyses of the 12 galaxies in the "Survey of H i in Extremely Low-mass Dwarfs" (SHIELD). We use multi-configuration interferometric observations of the H i 21 cm emission line from the Karl G. Jansky Very Large Array (VLA)22 to produce image cubes at a variety of spatial and spectral resolutions. Both two- and three-dimensional fitting techniques are employed in an attempt to derive inclination-corrected rotation curves for each galaxy. In most cases, the comparable magnitudes of velocity dispersion and projected rotation result in degeneracies that prohibit unambiguous circular velocity solutions. We thus make spatially resolved position-velocity cuts, corrected for inclination using the stellar components, to estimate the circular rotation velocities. We find 30 km s-1 for the entire survey population. Baryonic masses are calculated using single-dish H i fluxes from Arecibo and stellar masses derived from HST and Spitzer imaging. Comparison is made with total dynamical masses estimated from the position-velocity analysis. The SHIELD galaxies are then placed on the baryonic Tully-Fisher relation. There exists an empirical threshold rotational velocity, V < 15 km s-1, below which current observations cannot differentiate coherent rotation from pressure support. The SHIELD galaxies are representative of an important population of galaxies whose properties cannot be described by current models of rotationally dominated galaxy dynamics.

    Original languageEnglish (US)
    Article number89
    JournalAstrophysical Journal
    Volume832
    Issue number1
    DOIs
    StatePublished - Nov 20 2016

    Keywords

    • galaxies: dwarf
    • galaxies: irregular
    • galaxies: kinematics and dynamics
    • line: profiles
    • radio lines: galaxies
    • surveys

    Fingerprint Dive into the research topics of 'SHIELD: NEUTRAL GAS KINEMATICS and DYNAMICS'. Together they form a unique fingerprint.

  • Cite this

    McNichols, A. T., Teich, Y. G., Nims, E., Cannon, J. M., Adams, E. A. K., Giovanelli, R., Haynes, M. P., McQuinn, K. B. W., Salzer, J. J., Skillman, E. D., Bernstein-Cooper, E. Z., Dolphin, A., Elson, E. C., Haurberg, N., Józsa, G. I. G., Ott, J., Saintonge, A., Warren, S. R., Cave, I., ... Sistine, A. V. (2016). SHIELD: NEUTRAL GAS KINEMATICS and DYNAMICS. Astrophysical Journal, 832(1), [89]. https://doi.org/10.3847/0004-637X/832/1/89