ALMA Test Image - November 2010
This shows the well-known spiral NGC253, with an optical image of the whole galaxy on the left (credit: ESO). The ALMA test images show dense clouds of gas in the central regions of the galaxy: (middle) the CO J = 2-1 line at 230 GHz and (right) the continuum and CO J = 6-5 line at 690 GHz. The small ellipse in the bottom left hand corner of each of the ALMA test images indicates the angular resolution – that shows the size of the beam formed when the signals from the antennas are combined together. There were six antennas for the 230 GHz observations and only four for those at 690 GHz.