The Antennae Galaxies (aka NGC 4038 and NGC 4039) are a distorted pair of colliding spiral galaxies about 70 million light-years away, in the constellation of Corvus (The Crow). This false color image combines observations made in two different millimeter wavelength ranges from the European Southern Observatory’s ALMA with visible light observations from the Hubble Space Telescope.
Visible light—shown here mainly in blue—reveals the newborn stars in the galaxies, ALMA’s view shows the clouds of dense cold gas from which new stars form. The ALMA observations—shown here in red, pink and yellow—were made at specific wavelengths of millimetre and submillimetre light,tuned to detect carbon monoxide molecules in the otherwise invisible hydrogen clouds, where new stars are forming. Massive concentrations of gas are found not only in the hearts of the two galaxies but also in the chaotic region where they are colliding. The total amount of gas is billions of times the mass of the Sun, a rich reservoir of material for future generations of stars.
Image Credit: NASA / ESA / ESO