Asteroid 2005YU55 was throughly examined from groudn and space during its passage of Earth last week. It was examined by radar and at X-ray, UV and IR wavelengths

One of the world’s largest optical/infrared telescopes has captured near-infrared light images of asteroid YU55 as it was departing its close flyby of Earth the night of Nov. 8, 2011. The first unprocessed infrared images of the coal-black asteroid appear to confirm that the asteroid does not have any small companion satellites and that it may be somewhat smaller than some researchers have suspected. asteroid investigators William Merline and Peter Tamblyn of Southwest Research Institute and Chris Neyman of Keck Observatory took the IR images of the asteroid (left in the image)

"Swift's ultraviolet and X-ray capability gives scientists a unique perspective on comets and asteroids, expanding the spectral window beyond the radio, infrared and optical observations so well handled by big ground-based facilities," said Sergio Campana, a Swift team member at Brera Observatory in Merate, Italy.

Sources: Keck Observatory and SWIFT homepage