2008A&A...479..793Z

We performed deep optical observations of the field of an old, fast-moving radio pulsar PSR B1133+16 in an attempt to detect its optical counterpart and a bow shock nebula. The observations were carried out using the direct imaging mode of FORS1 at the ESO VLT/UT1 telescope in the B, R, and H_α bands. We also used archival images of the same field obtained with the VLT in the B band and with the Chandra/ACIS in X-rays. In the B band we detected a faint derived from a sample of pulsars detected in both spectral domains. No Balmer bow shock was detected, implying a low density of ambient matter around the pulsar. However, in the X-ray and H_α images we found the signature of a trail extending ∼4''-5'' behind the pulsar and coinciding with the direction of its proper motion. If confirmed by deeper studies, this is the first time such a trail has been seen in the optical and X-ray wavelengths. Further observations at later epochs are necessary to confirm the identification of the pulsar by the candidate's proper motion measurements.