Constraining neutron star properties with a new equation of state insensitive approach

Instead of parametrizing the pressure-density relation a neutron star (NS), one can parametrize its macroscopic properties such as mass ($M$), radius ($R$), and dimensionless tidal deformability ($\mathrm{\ensuremath{\Lambda}}$) to infer equation state (EOS) combining electromagnetic gravitational wave (GW) observations. We present new method $R(M)$ $\mathrm{\ensuremath{\Lambda}}(M)$ relations, which approximates candidate EOSs with accuracy better than 5% for all masses spans broad region $M\ensuremath{-}R\ensuremath{-}\mathrm{\ensuremath{\Lambda}}$ plane. Using this we combine $M\ensuremath{-}\mathrm{\ensuremath{\Lambda}}$ measurement from GW170817 GW190425, simultaneous $M\ensuremath{-}R$ pulsars PSR $\mathrm{J}0030+0451$ $\mathrm{J}0740+6620$ place joint constraints on NS properties. At 90% confidence, ${R}_{1.4}=12.0{5}_{\ensuremath{-}0.87}^{+0.98}\text{ }\text{ }\mathrm{km}$ ${\mathrm{\ensuremath{\Lambda}}}_{1.4}=37{2}_{\ensuremath{-}150}^{+220}$ $1.4\text{ }{M}_{\ensuremath{\bigodot}}$ NS, ${R}_{2.08}=12.6{5}_{\ensuremath{-}1.46}^{+1.36}\text{ $2.08\text{ NS. Furthermore, use inferred values maximum nonrotating ${M}_{\mathrm{max}}=2.5{2}_{\ensuremath{-}0.29}^{+0.33}\text{ investigate nature secondary objects in three potential star--black hole merger (NSBH) systems.