May 28 2021
The impressive image below displays the exceptionally contorted look of NGC 2276, an appearance due to two distinct astrophysical interactions—one with the superheated gas permeating galaxy clusters, and one with a closeby galactic neighbor.
This spectacular image from the NASA/ESA Hubble Space Telescope shows the trailing arms of NGC 2276, a spiral galaxy 120 million light-years away in the constellation of Cepheus. At first glance, the delicate tracery of bright spiral arms and dark dust lanes resembles countless other spiral galaxies. A closer look reveals a strangely lopsided galaxy shaped by gravitational interaction and intense star formation. Image Credit: ESA/Hubble & NASA, P. Sell.
NGC 2276’s interaction with the intracluster medium—the superheated gas present between the galaxies in galaxy clusters—has triggered a burst of star formation across one edge of the galaxy.
This star formation wave is evident as the bright, blue-tinged glow of newly developed huge stars toward the left side of this image, and provides the galaxy an oddly lopsided appearance. Also, NGC 2276’s latest burst of star formation is associated with the look of more exotic inhabitants—neutron stars and black holes present in the binary systems.
On the galaxy’s other side from this explosion of new stars, the gravitational attraction of a smaller companion is drawing the NGC 2276’s outer edges out of shape. Such an interaction with the small lens-shaped galaxy NGC 2300 has deformed the outermost spiral arms of NGC 2276, thereby providing the wrong idea that the bigger galaxy is directed face-on to Earth.
NGC 2276 and its troublesome companion NGC 2300 can both be viewed in the accompanying image, which displays a broader view of the galaxies in interaction.
In no case NGC 2276 is the only galaxy that has a weird look. The Atlas of Peculiar Galaxies—a catalog of exceptional galaxies published in 1966—consists of a menagerie of strange and fantastic galaxies, such as ring-shaped galaxies, spectacular galaxy mergers, and other galactic oddities.
As NGC 2276 suits an exceptionally contorted galaxy, it has the honor of being listed in the Atlas of Peculiar Galaxies two times—once for its lopsided spiral arms and another time for its interaction with its smaller neighbor NGC 2300.