A two-point diagnostic for the H II galaxy Hubble diagram

Kyle Leaf, Fulvio Melia

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


A previous analysis of starburst-dominated H II galaxies and H II regions has demonstrated a statistically significant preference for the Friedmann-Robertson-Walker cosmology with zero active mass, known as the Rh = ct universe, over Λcold dark matter (ΛCDM) and its related dark-matter parametrizations. In this paper, we employ a two-point diagnostic with these data to present a complementary statistical comparison of Rh = ct with Planck ΛCDM. Our two-point diagnostic compares, in a pairwise fashion, the difference between the distance modulus measured at two redshifts with that predicted by each cosmology. Our results support the conclusion drawn by a previous comparative analysis demonstrating that Rh = ct is statistically preferred over Planck ΛCDM. But we also find that the reported errors in the H II measurements may not be purely Gaussian, perhaps due to a partial contamination by non-Gaussian systematic effects. The use of H II galaxies and H II regions as standard candles may be improved even further with a better handling of the systematics in these sources.

Original languageEnglish (US)
Pages (from-to)4507-4513
Number of pages7
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Mar 1 2018


  • Cosmology: observations
  • Cosmology: theory
  • Distance scale
  • Galaxies: general
  • Large-scale structure of Universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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