Can modified gravity silence radio-loud pulsars?
Abstract
We perform magnetospheric studies in the modified gravity (MOG) framework to investigate effects of MOG on radio pulsar energetics with the main question being ``can MOG explain how radio pulsars turn into radio-quiet ones?'' In order to realize our aim, first, we have obtained exact vacuum analytical solutions of Maxwell equations for magnetic fields in the exterior of neutron stars in MOG. Then we have derived the analytical expressions for Goldreich-Julian charge density and unscreened parallel electric field solving the Poisson equation in the MOG frame. Calculations have shown that effects of MOG shift the radio pulsar death line up in $P\stackrel{\ifmmode \dot{}\else \textperiodcentered \fi{}}{P}$ diagram rend-ring objects that are radio loud in general relativity radio quiet in MOG. Using observational data, we estimate the upper limit for parameter $\ensuremath{\alpha}$ for the millisecond pulsars J2145-0750, J0024-7204D, and J0024-7204H, as $\ensuremath{\alpha}=1.6011$, 3.06528, and 0.9747, respectively.