Chandra X-ray Image of Westerlund 1
A very massive star collapsed to form a neutron star and not a black hole as expected, according to results from Chandra on the star cluster Westerlund 1. This discovery shows that nature has a harder time making black holes than previously thought.
Scale: Image is 300 by 270 arcsec
(Credit: NASA/CXC/UCLA/M.Muno et al.)

ESO Optical Image of Westerlund 1
This optical image of the super star cluster "Westerlund 1" is from the European Southern Observatory's 2.2-m MPG/ESO Wide-Field Imager. The foreground stars appear blue, while the hot massive members of the cluster look orange, and the cool massive ones come out red. Westerlund 1 is located in the Southern constellation Ara (the Altar). It was discovered in 1961 from Australia by Swedish astronomer Bengt Westerlund. This cluster is behind a huge interstellar cloud of gas and dust, which blocks most of its visible light.
Scale: Image is 300 by 270 arcsec
(Credit: ESO/WFI/2.2-m MPG)

2MASS Infrared Image of Westerlund 1
This image shows the star cluster "Westerlund 1" in infrared light as observed by the 2 Micron All-Sky Survey (2MASS). The field of view is approximately twice as large the Chandra image.
Scale: Image is 13 arcmin per side
(Credit: 2MASS/UMass/IPAC-Caltech/NASA/NSF)