Can the Hubble constant be determined from H II region diameters
Abstract
Recently published distances to nearby galaxies and isophotometric H II region diameters are used in an attempt to strengthen the local calibration of the galaxy luminosity versus H II region diameter correlation. It is shown that the best presently available data base yields a value of the Hubble constant, determined from the mean isophotal diameter alone, that is uncertain by approximately 40%. It is concluded that the method which Sandage and Tammann (1974) used to derive the scale size of the universe derives most of its weight from DDO luminosity classifications rather than from H II region diameter measurements and depends critically on the assumption that luminosity classifications of galaxies do not contain distance-dependent systematic errors.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1980
- DOI:
- 10.1086/157600
- Bibcode:
- 1980ApJ...235....1V
- Keywords:
-
- H Ii Regions;
- Hubble Constant;
- Interstellar Gas;
- Diameters;
- Galaxies;
- Hydrogen Ions;
- Luminosity;
- Nebulae;
- Astrophysics