Document Type
Article
Publication Date
8-1-1993
Abstract
Low Surface Brightness (LSB) galaxies appear to have low star formation rates despite their often quite normal H I contents as judged from global H I properties such as MH I/L and MH I/MT ratios. H I imaging with the Very Large Array of the National Radio Astronomy Observatory (the NRAO is operated by Associated Universities Inc. under contract with the National Science Foundation) of eight LSB galaxies shows that the H I is extended compared with the optical size and has average surface densities which are about a factor 2 lower than in High Surface Brightness (HSB) galaxies of the same type. The resolution of the H I imaging allows a rough rotation curve analysis for evaluating the critical density for star formation as formulated by Kennicutt [ApJ, 344, 685 (1989)]. The observed H I surface densities systematically fall below this critical density for most of the galaxies in this sample, in agreement with the low current star formation rates. From the optical surface photometry we conclude that the galaxies studied are in general late-type galaxies dominated by an exponential disk with a typical scale length of a few kpc. The B - R and V - I colors of the LSB galaxies are a few tenths of a magnitude bluer than those of HSB galaxies indicating that the disks of these galaxies have a mean young age.
Keywords
brightness distribution, galactic structure, star formation, Very Large Array (Vla), data reduction, spiral galaxies, astrophysics, galaxies: abundances; galaxies: peculiar, stars: formation
Publication Title
Astronomical Journal
Rights
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Recommended Citation
van der Hulst, J. M., Skillman, E. D., Smith, T. R., Bothun, G. D., McGaugh, S. S., and de Blok, W. J. G., “Star Formation Thresholds in Low Surface Brightness Galaxies”, The Astronomical Journal, vol. 106, IOP, p. 548, 1993. doi:10.1086/116660.
Manuscript Version
Final Publisher Version