http://arxiv.org/abs/1510.05545
We evaluate the local variance of the Hubble Constant $H_0$ with low-z Type Ia Supernovae (SNe). Our analyses are performed using a hemispherical comparison procedure to test whether the bulk flow motion can reconcile the measurement of the Hubble Constant $H_0$ from standard candles ($H_0 = 73.8 \pm 2.4 \; \mathrm{km \; s}^{-1}\; \mathrm{Mpc}^{-1}$) with that of the Planck’s Cosmic Microwave Background data ($67.8 \pm 0.9 \; \mathrm{km \; s}^{-1} \mathrm{Mpc}^{-1}$). We obtain that $H_0$ ranges from $68.9 \pm 0.5 \; \mathrm{km \; s}^{-1} \mathrm{Mpc}^{-1}$ to $71.2 \pm 0.7 \; \mathrm{km \; s}^{-1} \mathrm{Mpc}^{-1}$ through the celestial sphere, with maximal dipolar anisotropy towards the $(l,b) = (315^{\circ},27^{\circ})$ direction. Interestingly, this result is in good agreement with both $H_0$ estimations, as well as the bulk flow direction reported in the literature. In addition, we assess the statistical significance of this variance with different prescriptions of Monte Carlo simulations, finding a good concordance for its amplitude given the limitation of the SNe data set in terms of celestial coverage and their distance uncertainties. Additionally, we test the null hypothesis of this anisotropic direction being a random effect, albeit we can reject such hypothesis with good statistical significance. We then conclude that the conflict between these different Hubble Constant determinations can be unified by correctly taking into account the bulk flow motion of the local Universe.
C. Bengaly
Tue, 20 Oct 15
8/92
Comments: N/A
You must be logged in to post a comment.