Abstract
view Abstract Citations (38) References (22) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS H II regions as extragalactic distance indicators. II. Application of isophotal diameters. Kennicutt, R. C., Jr. Abstract Isophotal diameters of the largest H II regions in late-type galaxies are calibrated and applied to the galaxies measured by Sandage and Tammann (ST: 1974, 1975) in their calibration of the extragalactic distance scale. The results are found to corroborate ST's general conclusions regarding the usefulness of H II region diameters as distance indicators, but also to suggest the presence of systematic errors in the diameters determined by ST for distant H II regions. An increase of about 40% (from 50 to approximately 75 km/s per Mpc) in the derived Hubble constant is obtained by adopting more physically based isophotal diameters. The derived distance scales are then compared with cruder scales determined from the H-alpha fluxes of the largest H II regions and from the diameters of the galaxies themselves, as defined by the H II regions. The presence of systematic errors in ST's results is confirmed, and evidence is found suggesting a small change in the distance scale in the direction of increasing Hubble constant. Publication: The Astrophysical Journal Pub Date: March 1979 DOI: 10.1086/156894 Bibcode: 1979ApJ...228..696K Keywords: Astrometry; Galactic Radiation; H Ii Regions; Luminous Intensity; Nebulae; Calibrating; Diameters; Distance; H Alpha Line; Hydrogen Ions; Isophotes; Red Shift; Size Determination; Astrophysics; Distances:H II Regions; H II Regions; H II Regions:Late-Type Galaxies; Hubble Constant full text sources ADS | data products NED (17) Related Materials (3) Part 1: 1979ApJ...228..394K Part 3: 1979ApJ...228..704K Part 4: 1981ApJ...247....9K
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