Emission of the galaxy BzK-15504

H-alpha line emission of the galaxy BzK-15504, at cosmological redshift of 2.38, corresponding to a time of 3 billion years after the Big Bang. The colours show whether the ionised gas is moving away from us (red), toward us (blue) or is stationary (green), relative to the overall rest frame of the galaxy. These data, obtained with SINFONI and adaptive optics (resulting in a resolution of 0.15", or 4,000 light years at the distance of the galaxy), show for the first time very clearly the gas motions in such a distant galaxy in the Early Universe. The galaxy appears to be a disc, like our Milky Way, and rotates at 230 km/s about the yellow axis, which is centred on the nucleus of the galaxy (white cross).