CCAPP Seminar: "Sample variance in the local measurements of the Hubble constant" Heidi Wu (OSU)

Image
CCAPP Logo
September 19, 2017
11:30AM - 12:30PM
Location
PRB 4138

Date Range
Add to Calendar 2017-09-19 11:30:00 2017-09-19 12:30:00 CCAPP Seminar: "Sample variance in the local measurements of the Hubble constant" Heidi Wu (OSU) The Hubble constant H0 has recently been measured to percent-level precision, but two of the key results are in tension.  The local measurements using distance ladder have indicated H0 ~ 73 km/s/Mpc, while the global measurements using cosmic microwave background have indicated H0 ~ 67 km/s/Mpc.  In this talk, I will first review the methods and results of both local and global measurements, as well as previous attempts to alleviate this tension.  I will then present our efforts of using simulations to quantify the sample variance in the local measurements of H0.  Taking into account the inhomogeneous selection of type Ia supernovae, we find that this tension cannot be alleviated by sample variance or local density fluctuations.   I will conclude with future experiments that may resolve this tension. PRB 4138 Center for Cosmology and AstroParticle Physics (CCAPP) ccapp@osu.edu America/New_York public
Description

The Hubble constant H0 has recently been measured to percent-level precision, but two of the key results are in tension.  The local measurements using distance ladder have indicated H0 ~ 73 km/s/Mpc, while the global measurements using cosmic microwave background have indicated H0 ~ 67 km/s/Mpc.  In this talk, I will first review the methods and results of both local and global measurements, as well as previous attempts to alleviate this tension.  I will then present our efforts of using simulations to quantify the sample variance in the local measurements of H0.  Taking into account the inhomogeneous selection of type Ia supernovae, we find that this tension cannot be alleviated by sample variance or local density fluctuations.   I will conclude with future experiments that may resolve this tension.

Events Filters: