Peeking into a Neutron Star: Neutrons, Condensates, or Quarks?

Feryal Ozel (Univ of Arizona) - Mar 3, 2008 at 12:10 pm

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 mass and radius of neutron stars and is a key focus of Beyond Einstein science. I will discuss how we can break degeneracies between the neutron star parameters by combining recent developments in our understanding of neutron star atmospheres with observations of distinct spectroscopic phenomena from the same neutron star source. I will present a unique measurement of the mass and radius of the neutron star in EXO 0748-676. The high inferred mass and large radius of this neutron star rule out all the soft equations of state of neutron star matter. I will conclude with our recent radiation-hydrodynamical calculations of phenomena on accreting neutron stars that further reduce measurement biases.

The seminar will be held in 544 Campbell Hall.


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