title: Ultimate energy density of observable cold baryonic matter.
abstract: We demonstrate that the largest measured mass of a neutron star establishes an upper bound to the energy density of observable cold baryonic matter. An equation of state-independent expression satisfied by both normal neutron stars and self-bound quark matter stars is derived for the largest energy density of matter inside stars as a function of their masses. The largest observed mass sets the lowest upper limit to the density. Implications from existing and future neutron star mass measurements are discussed.
authors.affiliation: Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Lattimer
authors.forename: Madappa
authors.initials: M
authors.lastname: Prakash