Bayesian inference of neutron star properties in f(Q) gravity using NICER observations

Abstract

In this work, we investigate neutron stars (NSs) in the strong field regime within the framework of symmetric teleparallel f ( Q ) gravity, considering three representative models: linear, logarithmic, and exponential. While Bayesian studies of NS observations are well established in general relativity and curvature based modified gravity theories, such analyses in f ( Q ) gravity remain largely unexplored. For the first time we perform a Bayesian inference analysis by confronting theoretical NS mass-radius predictions with NICER observations of PSR J0030+0451, PSR J0740+6620, PSR J0437+4715, and PSR J0614+3329 in the background of nonmetricity based gravity. The dense matter equation of state is fixed to DDME2 in order to isolate the effects of modified gravity on NS structure. Our results indicate a statistical preference for the exponential f ( Q ) model over the linear and logarithmic cases, as supported by the Bayes-factor analysis, and show that its parameters are comparatively well constrained. For this model, we obtain a radius and tidal deformability at

of

$$R_{1.4} = 11.27^{+0.53}_{-0.36}\,\textrm{km}$$ R 1.4 = 11 . 27 - 0.36 + 0.53 km

and

$$\varLambda _{1.4} = 156.95^{+84.02}_{-41.73}$$ Λ 1.4 = 156 . 95 - 41.73 + 84.02

, respectively, consistent with current observational constraints. The median values of the maximum mass are found to be around

$$M_{\max }\approx 2.3M_\odot $$ M max ≈ 2.3 M ⊙

for all three constrained models. However, the upper parts of the 95% credible regions of the mass-radius relations extend beyond

$$2.5M_\odot $$ 2.5 M ⊙

and approach

$$\sim 3M_\odot $$ ∼ 3 M ⊙

within the adopted framework. This indicates the possibility of comparatively massive stable compact configurations in the Bayesian constrained parameter space. These results highlight the potential of NSs as powerful probes of symmetric teleparallel gravity in the strong field regime. We note that these results are conditional on the use of a fixed DDME2 equation of state and the coincident-gauge formulation adopted in this work.