logo observatoire

SÉMINAIRE DU LERMA
OBSERVATOIRE DE PARIS
logo lerma



!!! Lundi !!! 23 juin 2008 à 14h


77 avenue Denfert Rochereau, Paris 14



!!! Salle DANJON !!!, Observatoire de Paris





Mega-masers, Dark Energy and the Hubble Constant



Fred LO

NRAO, USA



Résumé : Powerful water maser emission (water mega-masers) can be found in accretion disks in the nuclei of some galaxies. Besides providing a measure of the mass at the nucleus, such mega-masers can be used to determine the angular diameter distance to the host galaxy, based on a simple model. We will explain the importance of determining the Hubble Constant to a high accuracy for constraining the equation of state of Dark Energy and present recent results of the Mega-maser Cosmology Project that has the goal of determining the Hubble Constant to ~3\%. In addition, we will also present a brief status report of NRAO facilities and some key science projects.