One of the most intriguing questions in the astrophysics of neutron stars is whether their interiors harbour deconfined quark matter. With the first multi-messenger observation of a binary neutron star merger (GW170817) new constraints became available for masses and radii of neutron stars.
I will discuss what we may infer for their mass and the central density at the onset of deconfinement under certain assumptions that may become testable in the near future. First, I will present examples of hadronic as well as quark matter equations of state and our attempts for a unified approach [1,2].
Then I will focus on the implications that precise simultaneous measurements of mass and radius in certain regions of the mass-radius diagram will have for disentangling the onset of deconfinement and the characteristics of the phase transition [3-5]. Such measurements are expected in near future from the NICER experiment.
I will discuss Bayesian analyses with the presently available data as well as fictitious mass-radius data that could in principle be the outcome of the NICER observations. Finally I will give an outlook on possible consequences for the structure of the QCD phase diagram, in particular for the existence of one or more critical endpoints of first-order phase transitions.
Literature:
[1] N.-U.F. Bastian, D.B. Blaschke, T. Fischer, G. Röpke, Universe 4 (2018) 67; arxiv:1804.10178
[2] N.-U.F. Bastian, D.B. Blaschke, arxiv:1812.11766
[3] S. Blacker, N.-U.F. Bastian, A. Bauswein, D.B. Blaschke, T. Fischer, arxiv:2006.03789
[4] D. Blaschke, A. Ayriyan, D.E. Alvarez-Castillo, H. Grigorian, Universe 6 (2020) 81
[5] M. Shahrbaf, D. Blaschke, S. Khanmohamadi, J. Phys. G (2020) to appear; arxiv:2004.14377
Filipe Veloso e Pedro Costa