This image shows the CO emission from the central few kiloparsecs of the nearby active galaxy NGC 5033. The distance to this galaxy is roughly 12.3 Mpc (megaparsecs) so the linear scale of the image is roughly 60 parsecs per second of arc. The contours and color image show the emission detected by our observations of the nuclear region of NGC 5033. These observations were made with the BIMA interferometer at Hat Creek, CA in the fall of 1994 and spring of 1995.

Why CO? Emission from CO (carbon monoxide) molecules is generally used by astronomers to trace regions of dense gas. These dense gas regions are for the most part made up of molecular hydrogen (H2) but because the gas in these regions is cold (roughly 5 to 30 degrees Kelvin) the radiation from hydrogen molecules is not detectable. Beside hydrogen and helium the most abundant elements are carbon, nitrogen, and oxygen. In general the strongest transitions of any molecular species observed are that of CO.