Constraints on a Putative Pulsar in SN 1987A

We assume that all the energy loss of the putative pulsar in SN 1987A would contribute to the luminosity of the remnant, which acts like a bolometer. The bolometric luminosity of SN 1987A provides an upper bound on the pulsar's rate of energy loss. An isolated pulsar spinning down by magnetic dipole radiation alone, with initial rotation periods of 10-30 ms, as extrapolated for galactic young pulsars, can have a luminosity below the bolometric bound if either the magnetic field is weak, B $\sim$ 10$^{9}-10^{10}$ G, or if it is so strong that the pulsar luminosity decays rapidly, B $\sim$ 10$^{16}$ G.