Bayesian inference of quark star equation of state using the NICER PSR J0030+0451 data

Abstract

We constrain the equation of state of quark stars within the Bayesian statistical approach using the mass and radius measurements of PSR J0030+0451 from NICER. Three types of bag models, with and without non-zero finite quark mass and/or superfluidity, are employed for quark stars made up with self-bound strange quark matter. We find the $90\%$ posterior credible boundary around the most probable values of the quark star maximum mass is $M_{\mathrm{TOV}}=2.38_{-0.23}^{+0.26}{M}_{\odot }$, within the model flexibility of the finite quark mass, the quark pairing gap, and the perturbative contribution from the one-gluon exchange. The radius of a canonical $1.4M_{\odot }$ quark star is $R_{1.4}\sim 12.3\mathrm{km}$, smaller than the results based on neutron star models.

7 pages, 4 figures, 3 tables; MNRAS in press. The analyses of quark star equation of state on the GW170817 and GW190425 data from LIGO/Virgo are reported in arXiv:2107.13997 (to appear in ApJL)