Heated polar caps in PSR 0656+14 and PSR 1055-52

We present new ASCA observations covering the 0.5-10 keV X-ray range of the cooling neutron star candidates PSR 0656+14 and PSR 1055-52. Previous ROSAT observations had shown that two-component models, either two blackbodies or a blackbody plus a power-law, provided the best spectral fits to their X-ray emission. The combined ASCA and ROSAT spectrum of PSR 0656+14 reveals two blackbody components with T approximate to 8 x 10(5) K and T approximate to 1.5 x 10(6) K and shows evidence that a power-law component is needed to account for higher energy photons. This three-component fit gives a reduced chi(2) that is half the value of a more conventional two component fit (1.3 as compared to 2.4). The fit to the combined spectrum for PSR 1055-52 yields a two-blackbody fit with T approximate to 8 x 10(5) K and T approximate to 3.7 x 10(6) K. Our results favor the existence of a hot polar cap in each of these pulsars with the ratio of the polar cap area to the neutron star surface area being 7 x 10(-3) and 3 x 10(-5) for PSR 0656+14 and PSR 1055-52, respectively. The results are compared to models that make predictions of polar cap heating processes.