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The cold gas content of bulgeless dwarf galaxies

Pilkington, K. ; Gibson, B. K. ; Calura, F. ; Brooks, A. M. ; Mayer, L. ; Brook, C. B. ; Stinson, G. S. ; Thacker, R. J. ; Few, C. G. ; Cunnama, D. ; Wadsley, J.

In: Monthly Notices of the Royal Astronomical Society, 2011, vol. 417, no. 4, p. 2891-2898

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    Title
    • The cold gas content of bulgeless dwarf galaxies
    Author
    • Pilkington, K.. Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE
    • Gibson, B. K.. Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE
    • Calura, F.. Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE
    • Brooks, A. M.. Theoretical Astrophysics, Caltech, 1200 E. California Blvd., Pasadena, CA 91125, USA
    • Mayer, L.. Institut für Theoretische Physik, University of Zürich, 8057 Zürich, Switzerland
    • Brook, C. B.. Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE
    • Stinson, G. S.. Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE
    • Thacker, R. J.. Department of Astronomy & Physics, St Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
    • Few, C. G.. Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE
    • Cunnama, D.. Physics Department, University of the Western Cape, 7535 Cape Town, South Africa
    • Wadsley, J.. Department of Physics & Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:299175
    Summary
    We present an analysis of the neutral hydrogen (H i) properties of a fully cosmological hydrodynamical dwarf galaxy, run with varying simulation parameters. As reported by Governato et al., the high-resolution, high star formation density threshold version of this galaxy is the first simulation to result in the successful reproduction of a (dwarf) spiral galaxy without any associated stellar bulge. We have set out to compare in detail the H i distribution and kinematics of this simulated bulgeless disc with what is observed in a sample of nearby dwarfs. To do so, we extracted the radial gas density profiles, velocity dispersion (e.g. velocity ellipsoid and turbulence) and the power spectrum of structure within the cold interstellar medium (ISM) from the simulations. The highest resolution dwarf, when using a high-density star formation threshold comparable to densities of giant molecular clouds, possesses bulk characteristics consistent with those observed in nature, though the cold gas is not as radially extended as that observed in nearby dwarfs, resulting in somewhat excessive surface densities. The lines-of-sight velocity dispersion radial profiles have values that are in good agreement with the observed dwarf galaxies, but due to the fact that only the streaming velocities of particles are tracked, a correction to include the thermal velocities can lead to profiles that are quite flat. The ISM power spectra of the simulations appear to possess more power on smaller spatial scales than that of the Small Magellanic Cloud. We conclude that unavoidable limitations remain due to the unresolved physics of star formation and feedback within parsec-scale molecular clouds