Neutron stars in f(R,Lm) gravity with realistic equations of state: joint-constrains with GW170817, massive pulsars, and the PSR J0030+0451 mass-radius from NICER data

• Published in: The European physical journal. C, Particles and fields Vol. 81; no. 11
• Main Authors: Lobato, R. V., Carvalho, G. A., Bertulani, C. A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2021; Springer Nature B.V; Springer Science + Business Media
• Subjects: Astronomy; Astrophysics and Cosmology; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Elementary Particles; Equations of state; Equilibrium equations; Gravitation theory; Gravitational waves; Hadrons; Heavy Ions; Mathematical analysis; Measurement Science and Instrumentation; Neutron stars; Neutrons; Nuclear Energy; Nuclear Physics; Physics; Physics and Astronomy; Pulsars; Quantum Field Theories; Quantum Field Theory; Regular Article - Theoretical Physics; Relativity; String Theory
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-021-09785-3

In this work, we investigate neutron stars (NS) in f ( R , L m ) theory of gravity for the case f ( R , L m ) = R + L m + σ R L m , where R is the Ricci scalar and L m the Lagrangian matter density. In the term σ R L m , σ represents the coupling between the gravitational and particles fields. For the first time the hydrostatic equilibrium equations in the theory are solved considering realistic equations of state and NS masses and radii obtained are subject to joint constrains from massive pulsars, the gravitational wave event GW170817 and from the PSR J0030+0451 mass-radius from NASA’s Neutron Star Interior Composition Explorer ( NICER ) data. We show that in this theory of gravity, the mass-radius results can accommodate massive pulsars, while the general theory of relativity can hardly do it. The theory also can explain the observed NS within the radius region constrained by the GW170817 and PSR J0030+0451 observations for masses around 1.4 M ⊙ .