Optical observations of psr j0205+6449

Abstract

PSR J0205+6449 is an X-ray and radio pulsar in supernova (SN) remnant 3C 58. We report on observations of the central region of 3C 58 using the 4.2-m William Herschel Telescope at the Isaac Newton Group of Telescopes, La Palma, with the intention of identifying the optical counterpart of PSR J0205+6449 and characterizing its pulsar wind nebula (PWN). Around the pulsar position, we identified extended emission with a magnitude of B = 23.97 +/- 0.10 ag, V = 22.95 +/- 0.05 mag and R = 22.15 +/- 0.03 mag consistent with a PWN. From the R-band image, we identified three knots with m(R) = 24.08 +/- 0.07 mag (o1), 24.15 +/- 0.07 mag (o2) and 24.24 +/- 0.08 mag (o3). We confirm the presence of an optical PWN around PSR J0205+6449 and give an upper limit of m(R) approximate to 24 for the optical magnitude of the pulsar. Furthermore, we make the tentative suggestion that our object o1, with an m(R) approximate to 24.08, is the optical counterpart. If confirmed, the pulsar would have an L-R/L-X approximate to 0.004 and an optical efficiency of about five per cent of the Crab pulsar. Such a low efficiency is more consistent with the characteristic age of the pulsar rather than that of SN 1181.