View of the Galactic Plane from the ATLASGAL survey (annotated)

Colour-composite annotated image of part of the Galactic Plane seen by the ATLASGAL survey. In this image, the ATLASGAL submillimetre-wavelength data are shown in red, overlaid on a view of the region in infrared light, from the Midcourse Space Experiment (MSX) in green and blue. The total size of the image is approximately 42 degrees by 1.75 degrees.

Some of the most prominent features visible in the image are (from left to right):

• Messier 20 (the Trifid Nebula): A nebula containing an open cluster of stars as well as a stellar nursery. The name “Trifid” refers to the way that dense dust appears to divide it into three lobes at visible wavelengths.
• Sagittarius B2 (Sgr B2): One of the largest clouds of molecular gas in the Milky Way, this dense region lies close to the Galactic Centre and is rich in many different interstellar molecules.
• Galactic Centre: The centre of the Milky Way, home to a supermassive black hole more than four million times the mass of our Sun. It is about 25,000 light-years from Earth.
• NGC 6357: A diffuse nebula containing the open cluster Pismis 24, home to several very massive stars.
• NGC 6334: An emission nebula also known as the “Cat’s Paw Nebula”.
• RCW 120: A region where an expanding bubble of ionised gas about ten light-years across is causing the surrounding material to collapse into dense clumps that are the birthplaces of new stars.
• The Norma Arm: The region of somewhat brighter emission extending over about 10 degrees on the right-hand side of the image corresponds to the position of the Norma Arm, one of the spiral arms of the Milky Way.