The collective research results of an international team of astrophysicists studying the Hubble constant is featured in the July issue of the journal Nature Astronomy. Participating from Princeton’s Department of Astrophysical Sciences include the project’s leader, Kenta Hotokezaka, the Lyman Spitzer, Jr. Postdoctoral Fellow and Kento Masuda, NASA Sagan Postdoctoral Fellow.
Important in the study of cosmology, the Hubble constant is used to measure the expansion rate of the Universe. The 2017 discovery of the merger of two neutron stars, GW170817, has led to using new radio observations analyzing gravitational waves (GW) and electromagnetic localization (EM) as an independent measurement of the Hubble constant. This new method challenges the two most successful techniques for measuring the Hubble constant which are Planck predicted observations of the microwave background and Type la supernovae measurements of exploding stars. Since these two existing measurement standards are not in agreement with one another, Hotokezaka and his team decided to determine a third, independent value of the Hubble constant to better understand the expansion rate of the Universe.
Princeton University’s online news page features a story about the research; the article can be read here