Figure 5: Top: Fitting curves (solid curve) and numerical results (points) of the universal I-Love
(left) and Q-Love (right) relations for various equations of state, normalized as ,
and , is the neutron-star mass, is
the tidal Love number, is the rotation-induced quadrupole moment, and is the magnitude
of the neutron-star spin angular momentum. The neutron-star central density is the parameter varied
along each curve, or equivalently the neutron-star compactness. The top axis shows the neutron star
mass for the APR equation of state, with the vertical dashed line showing . Bottom:
Relative fractional errors between the fitting curve and the numerical results. Observe that these
relations are essentially independent of the equation of state, with loss of universality at the 1% level.
Image reproduced by permission from , copyright by APS.