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

R. V. Lobato; G. A. Carvalho; C. A. Bertulani

doi:10.1140/epjc/s10052-021-09785-3

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2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2021) 81: 1013
https://doi.org/10.1140/epjc/s10052-021-09785-3

Regular Article - Theoretical Physics

Neutron stars in $f (R, L_{m})$ $f(\mathtt {R,L_m})$ gravity with realistic equations of state: joint-constrains with GW170817, massive pulsars, and the PSR J0030+0451 mass-radius from NICER data

R. V. Lobato¹^,2^a, G. A. Carvalho³ and C. A. Bertulani¹

¹ Department of Physics and Astronomy, Texas A&M University-Commerce, 75429, Commerce, TX, USA
² Departamento de Fisica, Universidad de los Andes, Bogotá, Colombia
³ Instituto de Pesquisa e Desenvolvimento (IP&D), Universidade do Vale do Paraíba, 12244-000, São José dos Campos, SP, Brazil

^a r.vieira@uniandes.edu.co

Received: 1 June 2021
Accepted: 31 October 2021
Published online: 18 November 2021

Abstract

In this work, we investigate neutron stars (NS) in $f (R, L_{m})$ $f(\mathtt {R,L_m})$ theory of gravity for the case $f (R, L_{m}) = R + L_{m} + σ R L_{m}$ $f(\mathtt {R,L_m})= \mathtt {R}+ \mathtt {L_m}+ \sigma \mathtt {R}\mathtt {L_m}$ , where $R$ $\mathtt {R}$ is the Ricci scalar and $L_{m}$ $\mathtt {L_m}$ the Lagrangian matter density. In the term $σ R L_{m}$ $\sigma \mathtt {R}\mathtt {L_m}$ , $σ$ $\sigma$ 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 $1.4 M_{⊙}$ $1.4~M_{\odot }$ .

© This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply 2021

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