An H I survey of Nilson dwarf galaxies. II. Statistical properties.
Abstract
Results are reported for a statistical analysis of a sample of low-surface-brightness (LSB) objects consisting of the Nilson (1973) dwarf galaxies and the DDO dwarf galaxies detected by Fisher and Tully (1975). It is concluded that: (1) the Nilson catalog is fairly complete for all galaxies with a Nilson blue diameter larger than 1 arcmin; (2) LSB objects include a broad continuum of galaxies ranging from 'true' dwarfs (absolute photographic magnitude at least -16) to more luminous (absolute photographic magnitude less than -16) but very LSB systems; (3) in general, the LSB galaxies have larger hydrogen mass/photographic luminosity ratios and hydrogen/total mass ratios than late-type galaxies of comparable luminosity, implying that only a small fraction of the total gas has been converted into stars; and (4) the LSB galaxies have a total mass/linear radius ratio 3 to 9 times smaller than that of Sdm-Sm galaxies, which may be too small for the LSB galaxies to maintain a density wave necessary for efficient star formation.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1979
- DOI:
- 10.1086/157232
- Bibcode:
- 1979ApJ...231..680T
- Keywords:
-
- Galactic Structure;
- Hydrogen Atoms;
- Line Spectra;
- Microwave Spectra;
- Radio Sources (Astronomy);
- Statistical Analysis;
- Density Distribution;
- Luminosity;
- Radio Astronomy;
- Space Density;
- Tables (Data);
- Astrophysics;
- Dwarf Galaxies:Neutral Hydrogen;
- Dwarf Galaxies:Statistics;
- Dwarf Galaxies:Surveys