2017/10/16 by David Fernández-Arenas, E. Terlevich, Elena Terlevich +9 · 6 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Cepheid variable #Cosmic distance ladder #Galaxies: Formation, Evolution, Phenomena #Galaxy #Hubble's law #Luminosity #Physics #Redshift #Spiral galaxy #Stars #Stellar, planetary, and galactic studies #Velocity dispersion #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stx2710
30 pages, 28 figures, Accepted to be published in MNRAS
arxiv created 2017/10/16 · openalex publication_date 2017/10/17 · openalex created_date 2017/11/10 · arxiv updated 2017/12/20 · openalex updated_date 2026/08/05
The relationship between the integrated Hβ line luminosity and the velocity dispersion of the ionized gas of HII galaxies and giant HII regions represents an exciting standard candle that presently can be used up to redshifts z ~ 4. Locally it is used to obtain precise measurements of the Hubble constant by combining the slope of the relation obtained from nearby (z ≤ 0.2) HII galaxies with the zero point determined from giant HII regions belonging to an `anchor sample' of galaxies for which accurate redshift-independent distance moduli are available. We present new data for 36 giant HII regions in 13 galaxies of the anchor sample that includes the megamaser galaxy NGC 4258. Our data is the result of the first four years of observation of our primary sample of 130 giant HII regions in 73 galaxies with Cepheid determined distances. Our best estimate of the Hubble parameter is 71.0±2.8(random)±2.1(systematic) km /s Mpc This result is the product of an independent approach and, although at present less precise than the latest SNIa results, it is amenable to substantial improvement.