Speaker
Mihael Kodric
(USM)
Description
We obtained the currently largest near-infrared Cepheid sample in the Andromeda Galaxy (M31). Despite of having random phased observations, the obtained period-luminosity relations (PLRs) have a very small dispersion. This remarkably small dispersion allows us to show that the PLRs are significantly better described by a broken slope at ten days than a linear slope. The Riess et al. (2012) M31 Cepheid sample is a subsample of our data, but our data gives a different PLR zero point if the same slope is used for both samples. That leads to an 3.2% larger Hubble constant H0 for our data. This result shows that sample selection influences the H0 estimation and begs the question how close we are to the 1% goal of determining H0.
