Alternative High-z Cosmic Tracers and the Dark Energy Equation of State

Abstract

We propose to use alternative cosmic tracers to measure the dark energy equation of state and the matter content of the Universe [w(z) & Ω_m]. Our proposed method consists of two components: (a) tracing the Hubble relation using HII-like starburst galaxies, as an alternative to SNIa, which can be detected up to very large redshifts, z~4, and (b) measuring the clustering pattern of X-ray selected AGN at a median redshift of ~1. Each component of the method can in itself provide interesting constraints on the cosmological parameters, especially under our anticipation that we will reduce the corresponding random and systematic errors significantly. However, by joining their likelihood functions we will be able to put stringent cosmological constraints and break the known degeneracies between the dark energy equation of state (whether it is constant or variable) and the matter content of the universe and provide a powerful and alternative rute to measure the contribution to the global dynamics, and the equation of state, of dark energy. A preliminary joint analysis of X-ray selected AGN (based on a small XMM survey) and the currently largest SNIa sample (Kowalski et al 2008), provides: Omega_m=0.28^{+0.02}_{-0.04} and w=-1.0 +-0.1.

19 pages, 11 figures, to appear in JOP, proceedings of the "Recent Developments in Gravity, NEB XIII" conference, held in Thessaloniki, Macedonia, Greece, 4-6 June 2008

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Cited by in corpus (10)

• Determining the range of validity of quasar X-ray and UV flux measurements for constraining cosmological model parameters
• Cosmological constraints from HII starburst galaxy apparent magnitude and other cosmological measurements
• A Strategy to Measure the Dark Energy Equation of State using the HII galaxy Hubble Relation & X-ray AGN Clustering: Preliminary Results
• Cosmological constraints from higher-redshift gamma-ray burst, HII starburst galaxy, and quasar (and other) data
• The L-sigma Relation of Local HII Galaxies
• Constraints on dark energy from H II starburst galaxy apparent magnitude versus redshift data
• Evolution of Dark Energy Perturbations in Scalar-Tensor Cosmologies
• Using newest VLT-KMOS HII Galaxies and other cosmic tracers to test the $\Lambda$CDM tension
• Low- and high-redshift H II starburst galaxies obey different luminosity-velocity dispersion relations
• Cosmological Constraints using the newest VLT-KMOS HII Galaxies and the full Planck CMB spectrum