6 May 2010
6 May 2010
Speaker: Feryal Ozel (University of Arizona)
Title:Astrophysical Measurement of the Equation of State of Neutron Star
Abstract:Neutron stars are the densest objects in the universe and may contain
hyperon-dominated matter, condensed mesons, or even deconfined or
strange quark matter. Because of their low temperatures and high
chemical potentials, the physical conditions in their interiors differ
greatly from the dense conditions of the early universe or those
achieved at hadron colliders. This region of the QCD phase diagram can
best be probed through astrophysical observations that measure the
masses and radii of neutron stars. I will discuss how we can break
degeneracies in the measurements of neutron star properties by combining
recent developments in our understanding of their atmospheres with
observations of multiple spectroscopic phenomena from X-ray binaries.
I will present unique measurements of the masses and radii of three
neutron stars in low-mass X-ray binaries and show the equations of
state of neutron star matter that are compatible with these observations.
These measurement constrain, for the first time, the pressure of cold matter
above nuclear saturation density and offer tantalizing evidence for new
degrees of freedom at ultrahigh densities.