Searching for Debris Disks around Seven Radio Pulsars

Abstract

We report on our searches for debris disks around seven relatively nearby radio pulsars, which are isolated sources that were carefully selected as targets on the basis of our deep K_s -band imaging survey. The K_s images obtained with the 6.5 m Baade Magellan Telescope at Las Campanas Observatory are analyzed together with the Spitzer/IRAC images at 4.5 and 8.0 μm and the WISE images at 3.4, 4.6, 12, and 22 μm. No infrared counterparts of these pulsars are found, with flux upper limits of ~μJy at near-infrared (λ < 10 μm) and ~10-1000 μJy at mid-infrared wavelengths (λ > 10 μm). The results of this search are discussed in terms of the efficiency of converting the pulsar spin-down energy to thermal energy and X-ray heating of debris disks, with a comparison made of the two magnetars 4U 0142+61 and 1E 2259+586, which are suggested to harbor a debris disk.