Tidal deformabilities of neutron stars in scalar-Gauss-Bonnet gravity and their applications to multimessenger tests of gravity

The spacetime surrounding compact objects such as neutron stars and black holes provides an excellent place to study gravity in the strong, nonlinear, dynamical regime. Here, effects of strong curvature can leave their imprint on observables which we may use gravity. Recently, NICER provided a mass radius measurement isolated star using x-rays, while LIGO/Virgo measured tidal deformability through gravitational waves. These measurements be used test relation between compactness that are known universal general relativity. take (shift-symmetric) scalar-Gauss-Bonnet (motivated by low-energy effective theory string theory) example whether one apply theory. To do so, this paper is mostly devoted theoretically constructing tidally deformed solutions perturbatively calculate for first time. We find remains fixed dimensionless coupling constant though different from also present another directly applied observations NICER. For equations state considered paper, it still inconclusive meaningful bounds scalar Gauss-Bonnet with new relations. However, found bound pulsar $\mathrm{J}0740+6620$ comparable other existing hole observations.