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For refcode 1988MNRAS.235..297M:
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Copyright by Royal Astronomical Society. 1988MNRAS.235..297M Giant H II regions as distance indicators - II. Application to H II galaxies and the value of the Hubble constant Jorge Melnick European Southern Observatory, Karl Schwarzschild Str. 2, D-8046, Garching bei Munchen, FRG Roberto Terlevich Royal Greenwich Observatory Mariano Moles Instituto de Astrofisica de Andalucia Accepted 1988 March 22. Received 1988 February 26; in original form 1987 April 28 Summary. The (integrated) H{beta} luminosities of giant H II regions and of H II galaxies (giant H II regions in dwarf galaxies) can be predicted with an accuracy comparable to the observational errors from the velocity widths of their emission-line profiles and the nebular oxygen abundances. The zero point of the correlation between these parameters is calibrated using the homogeneous sample of giant H II regions in nearby galaxies with well determined distances discussed in the first paper of this series. The calibration is applied to distant H II galaxies to obtain a value for Hubble's constant H_0_. After correcting the fluxes for Malmquist bias and the radial velocities for the motion of the Local Group we find H_0_=89+/-10 km^-1^ Mpc^-1^. From four H II galaxies in the Virgo cluster, a true distance modulus of (m-M)_Vir_=30.9+/-0.15 is obtained for that cluster. The effects of the large-scale inhomogeneities in the Hubble flow shown to exist by Dressler et al. are emphasized and illustrated using the distance to Virgo to calibrate the kinematical distances of six rich clusters out to redshifts of ~9000 km s^-1^. We conclude that values of H_0_ obtained using 'nearby' (cz < 5000 km s^-1^) galaxies may be systematically biased by streaming motions. A detailed discussion of possible systematic errors is presented.
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