Open AccessH ii galaxies as deep cosmological probes
Author(s) -
Melnick Jorge,
Terlevich Roberto,
Terlevich Elena
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03112.x
Subject(s) - physics , redshift , astrophysics , hubble's law , galaxy , cosmic distance ladder , cosmological constant , metric expansion of space , universe , diagram , cosmology , dark energy , astronomy , theoretical physics , statistics , mathematics
We re‐investigated the use of the Hubble diagram to measure the cosmological constant (Λ) and the mass density of the Universe (Ω M ). We find an important focusing effect in Λ for redshifts of about 3. This effect implies that the apparent magnitude of a standard candle at redshifts z =2–3 has almost no dependence on Λ for Ω M >0.2. This means that Ω M can be measured independently of Ω Λ by targeting the redshift range according to an estimate of the value of Ω M . We explore the evidence in support of the suggestion that extreme starburst galaxies, also known as H ii galaxies, can be used as distance estimators over a wide range of redshifts and reaching very high values. We have compiled literature data of H ii galaxies up to z ∼3 and found a good correlation between their luminosity and velocity dispersion measured from their strong emission lines, thus confirming the correlation already known to exist for H ii galaxies in the nearby Universe. Several systematic effects, such as age, extinction, kinematics and metallicity, are discussed, as well as the effects of different cosmologies.