Near-infrared, kilosecond variability of the wisps and jet in the Crab pulsar wind nebula

Abstract

We present a time-lapse sequence of 20 near-infrared (J and K′ band) snapshots of the central 20 × 20 of the Crab pulsar wind nebula, taken at subarcsecond resolution with the Hokupa'a/QUIRC adaptive optics camera on the Gemini North Telescope and sampled at intervals of 10 minutes and 24 hr. It is observed that the equatorial wisps and polar knots in the termination shock of the pulsar wind appear to fluctuate in brightness on kilosecond timescales. Maximum flux variations of ±24% ±4% and ±14% ±4% relative to the mean (in 1.2 ks) are measured for the wisps and knots, respectively, with the greatest statistical significance in the J band, where the nebula background is less prominent. The J ..