Galaxy Family Portrait

The Hubble Space Telescope snapped a family portrait of a pair of galaxies in the nearby Virgo galaxy, where a huge elliptical galaxy dwarfs its spiral sibling.

Arp 116
Messier 60, the fuzzy elliptical, poses with its spiral sibling, NGC 4647, for a Hubble family portrait.
NASA, ESA

The Hubble Space Telescope snapped this picture of a pair of galaxies “posing” for a family portrait in the nearby Virgo galaxy cluster, just 55 million light-years away.

The elliptical galaxy, known as Messier 60, dwarfs its spiral sibling, NGC 4647. And that’s not an optical illusion. The galaxies are close neighbors, so the difference in size is real. So is the contrast in color and structure. The larger galaxy glows a golden color thanks to its huge mass of older, cooler, and redder stars; meanwhile, clusters of newborn stars shine hot and blue in the spiral galaxy.

The differences don’t end there. A monstrous black hole 4.5 billion times the mass of our Sun lurks in M60, but if any black hole lives in NGC 4647, astronomers have yet to find conclusive evidence of its existence.

Weirdly, three different astronomers discovered M60 independently within days of each other in April 1779. NGC 4647 waited another five years for discovery by William Herschel. Though the two are close companions, astronomers still aren’t sure whether they’re interacting. If they were, the gravitational interactions might distort the galaxies or cause sudden bursts of star formation, neither of which are seen. But the detailed Hubble observations may reveal features of a nascent interaction.

Arp 116 zoom-out
A ground-based telescope zooms out on the galaxy pair Arp 116 and its environment in the Virgo galaxy cluster.
NASA, ESA, Digitized Sky Survey 2 (Acknowledgement: Davide De Martin)
Find Them Yourself

The galaxy duo makes a good deep-sky target for the telescope. M60 (RA: 12h 43m, Dec: 11d 33m) is relatively bright at 9th magnitude, an egg-shaped fuzz-ball with a slightly yellow hue. M60 is notable for its starlike nucleus. NGC 4647 lies to the northwest of M60 and, because it lies so close to M60 and is a magnitude fainter, it’s best seen using averted vision.

CATEGORIES
Galaxies, News
Monica Young

About Monica Young

Monica Young, a professional astronomer by training, is web editor of Sky & Telescope, where she creates, manages, and maintains website content, and contributes to the magazine.

One thought on “Galaxy Family Portrait

  1. Darian-RachalDarian Rachal

    On shots like this I always get a kick out of finding some tiny, obscure galaxy in the background and imagining it is the Milky Way, including the earth and all it’s human activity.

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