M-60 is on the right, NGC 4647 is on the left. CCD image taken with an ST-9E CCD camera thru Kopernik's 20-inch F/8.1 telescope. The field of view is about 8x8 arc minutes, with South at the top. Exposure = 10 minutes.
Note (up-date): the small streak to the left of M-60 was identified as Asteroid (35642) 1998 KF53. It was magnitude 17.3 when it moved thru the field of view while we were taking this image!
Quote from the Deep Sky Field Guide to Uranometria 2000:
M-60: Very bright center, smooth nebulosity.
NGC 4647: Very small, bright nucleus, very many knotty arms, outer dark lane on one side. Contact pair with M-60.
Quote by Johann G. Koehler (April 11th and 13th, 1779): “(M-59 and M-60) Two very small nebulae, hardly visible in a 3-foot telescope; one above the other.”
Quote by Barnabus Oriani (April 12th, 1779): “Very pale and looking exactly like the comet.”
Quote by Charles Messier (April 15th, 1779): “'A nebula in Virgo, a little more distinct than the two preceding, (M 58 and M 59)........ Reported on the chart of the comet of 1779. He discovered the three nebulae while observing the comet which passed very close to them. The latter passed so near on the 13th and 14th April that they were both in the same field of view and he could not see it. It was not until the 15th, while looking for the comet, that he perceived the nebula. None of the three nebulae appears to contain a star”
Johann G. Koehler of Dresden discovered M-60 and nearby M-59 in April 1779 while observing the comet of that year. The comet passed near the two galaxies. The next evening Italian astronomer Barnabus Oriani found M-60 while observing the comet, and while he apparently missed nearby M-59, he did fine M-49 and M-60. Charles Messier independently discovered M-60 a few nights later while observing the same comet.
M-60, like M-49 and M-87, is a giant elliptical galaxy. Its mass, as given by Erik Holmberg in his 1964 Catalogue of External Galaxies, is about one trillion solar masses, roughly 5 times that of the Milky Way. Compared with M 32, the elliptical companion of the Andromeda Galaxy, it is 200 times as massive. Its diameter is about 120,000 light years.
The faint spiral galaxy, NGC 4647 is nearly in contact with M-60. It has a mass of about 10 billion suns, and its small bright nucleus falls into the least energetic class of Active Galactic Nuclei. This galaxy was the host of 15th magnitude Type I supernova 1979a.
The M-60 - NGC 4647 pair makes up Arp 116, and is classified by Arp as one of his "Elliptical and E-like galaxies close to and perturbing spirals." Arp noted that for NGC 4647 "Absorption heavier on spiral side away from Elliptical galaxy." Many astronomers think that giant elliptical galaxies like M-60 form when two or more smaller galaxies collide and combine into a single galaxy. Arp 116 could be an example of this process.
Classification: SAB(rs)c III-IV
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George Normandin, KAS
April 23rd, 2002