Galaxies NGC 4550 and NGC 4551

The close pair of galaxies NGC 4550 and NGC 4551 lies about 18 arc minutes south of the much brighter elliptical galaxy M-89. Although they appear close together on the sky there is no sign of interaction between the pair, and they have different red shifts. Both are probably a part of the Virgo Galaxy Cluster. Older catalogs list NGC 4550 as an edge-on barred spiral galaxy. However, relying on more recent observations, many astronomers now believe that it is a lenticular galaxy with two odd counter-rotating stellar disks. NGC 4551 is usually considered an elliptical galaxy. The classification of both of these galaxies remains uncertain.

VCC 1606 and VCC 1637 are just visible in the Kopernik image above. They are more apparent in the original uncompressed image (too large for posting on the web). Both are probably dwarf elliptical galaxies that are a part of the Virgo Galaxy Cluster, but they may also be more distant background galaxies.

QSO 1232+125 appears to be simply a 17.2 magnitude star. However its spectra reveals it to be a Quasar, one of the strangest objects in the sky. This object, like all quasars, is moving away from us at a substantial fraction of the speed of light. Using the Hubble Law its estimated distance is more than 10 Billion Light Years. The light captured in the Kopernik image was already more than half way here when the sun was first formed. Based on observations, including those of the Hubble Space Telescope, most astronomers now believe that these incredibly bright objects are massive black holes at the cores of the distant galaxies of the early universe. The light comes from super-heated gas spiraling into the black hole. There is much less gas in galaxies now, so the central black holes in close galaxies, and our own Milky Way, no longer shine with the brightness of the Quasars.

Click below to

George Normandin, KAS

June 18th, 2000