HIGH-VELOCITY CLOUDS IN THE NEARBY SPIRAL GALAXY M 83
Author(s)
Bregman, Joel N.; Wakker, Bart P.; Miller, Eric D
DownloadMiller-2009-HIGH-VELOCITY CLOUDS.pdf (5.412Mb)
PUBLISHER_POLICY
Publisher Policy
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Terms of use
Metadata
Show full item recordAbstract
We present deep H I 21 cm and optical observations of the face-on spiral galaxy M 83 obtained as part of a project to search for high-velocity clouds (HVCs) in nearby galaxies. Anomalous-velocity neutral gas is detected toward M 83, with 5.6 × 107 M ☉ of H I contained in a disk rotating 40-50 km s–1 more slowly in projection than the bulk of the gas. We interpret this as a vertically extended thick disk of neutral material, containing 5.5% of the total H I within the central 8 kpc. Using an automated source detection algorithm to search for small-scale H I emission features, we find eight distinct, anomalous-velocity H I clouds with masses ranging from 7 × 105 to 1.5 × 107 M ☉ and velocities differing by up to 200 km s–1 compared to the H I disk. Large on-disk structures are coincident with the optical spiral arms, while unresolved off-disk clouds contain no diffuse optical emission down to a limit of 27 r' mag per square arcsec. The diversity of the thick H I disk and larger clouds suggests the influence of multiple formation mechanisms, with a galactic fountain responsible for the slowly rotating disk and on-disk discrete clouds, and tidal effects responsible for off-disk cloud production. The mass and kinetic energy of the H I clouds are consistent with the mass exchange rate predicted by the galactic fountain model. If the HVC population in M 83 is similar to that in our own Galaxy, then the Galactic HVCs must be distributed within a radius of less than 25 kpc.
Date issued
2009-02Department
MIT Kavli Institute for Astrophysics and Space ResearchJournal
Astrophysical Journal
Publisher
Institute of Physics/American Astronomical Society
Citation
Miller, Eric D., Joel N. Bregman, and Bart P. Wakker. “HIGH-VELOCITY CLOUDS IN THE NEARBY SPIRAL GALAXY M 83.” The Astrophysical Journal 692, no. 1 (February 10, 2009): 470–491. © 2009 American Astronomical Society.
Version: Final published version
ISSN
0004-637X
1538-4357