SIMBAD references

After reviewing the multifrequency behaviour of the Isolated Neutron Stars detected so far, we analyze for each object the efficiency of conversion of the star's rotational energy loss into optical, X and γ radiation. Although the number of pulsars detected at different wavelengths is rather limited, a pattern is seen to emerge from our analysis pointing towards the period derivative as the leading parameter to describe the multifrequency emission of INS. One object in particular, PSR 1509-58, stands out as archetypal for the {dot}(P)-dependence of its luminosity at different wavelengths.