Can Old Galaxies at High Redshifts and Baryon Acoustic Oscillations Constrain H_0?

A new age-redshift test is proposed in order to constrain $H_0$ with basis on the existence of old high redshift galaxies (OHRG). As should be expected, the estimates of $H_0$ based on the OHRG are heavily dependent on the cosmological description. In the flat concordance model ($\Lambda$CDM), for example, the value of $H_0$ depends on the mass density parameter $\Omega_M=1 - \Omega_{\Lambda}$. Such a degeneracy can be broken trough a joint analysis involving the OHRG and baryon acoustic oscillation (BAO) signature. In the framework of the $\Lambda CDM$ model our joint analysis yields a value of $H_0=71^{+4}_{-4}\kms$ Mpc$^{-1}$ ($1\sigma$) with the best fit density parameter $\Omega_M=0.27\pm0.03$. Such results are in good agreement with independent studies from the {\it{Hubble Space Telescope}} key project and the recent estimates of WMAP, thereby suggesting that the combination of these two independent phenomena provides an interesting method to constrain the Hubble constant.

Comment: 16 pages, 6 figures, 1 table