What is Dark Energy?

...one of the fundamental unknowns in contemporary cosmology.

The goal of the Water Maser Cosmology Project is to constrain the fundamental nature of Dark Energy via measurement of the Hubble constant with a few percent accuracy. Today, the best estimate of the Hubble constant is uncertain by perhaps 10% when all things are considered.

The WMCP targets active galactic nuclei that contain sources of water maser emission in the accretion disks around central supermassive black holes. Radio interferometer mapping and long-term spectroscopic monitoring of these masers enables measurement of high-accuracy geometric distances, which when combined with known galaxy redshifts, yields a robust estimate of the Hubble constant independent of the systematics that affect estimates today.

	The Dark Universe	Maser Cosmology
	Maser Cosmology Recipe	Are many AGN known to contain masers?

Group member publications related to the WMCP