Images of galaxies colliding
kenobi-wan-obi: NGC 474 The multiple layers of emission appear strangely complex and unexpected given the relatively featureless appearance of the elliptical galaxy in less deep images. Image Copyright: Canada-France-Hawaii Telescope (Jean-Charles Cuillandre)/Coelum (Giovanni Anselmi)
The “Black Widow” pulsar is moving through the galaxy at a speed of almost a million kilometers per hour. A bow shock wave due to this motion is visible to optical telescopes, shown in this image as the greenish crescent shape. The pressure behind the bow shock creates a second shock wave that sweeps the cloud of high-energy particles back from the pulsar to form the cocoon.
Active Black Hole Squashes Star Formation New data from the Herschel Space Observatory shows that galaxies with the most powerful, active, supermassive black holes at their cores produce fewer stars than galaxies with less ones. (www.nasa.gov/...) Image Credit: NASA/JPL-Caltech
Astronomy Photographer of the Year 2012 - Winner. M51 The Whirlpool Galaxy by Martin Pugh. M51 or the Whirlpool is the archetypal spiral galaxy and for centuries astronomers have studied it in order to understand how galaxies form and evolve. Here the photographer has made use of exceptionally stable atmospheric conditions, minimising the twinkling or ‘seeing’ caused by air turbulence to produce a sharp, clear image in which every detail of the galaxy is visible.