“Abode of Space-Faring Civilizations?” –Giant Elliptical Galaxy NGC 4874 Holds 30,000 Globular Star Clusters: ‘Most in the Universe’

 

Coma (1)

 

A giant elliptical galaxy, about ten times larger than the Milky Way, observed by the Hubble Space Telescope harbors more than 30,000 globular clusters, which according to astronomer Rosanne DiStefano at the Harvard-Smithsonian CfA "might be the first place in which intelligent life is identified in our galaxy." Globular star clusters are extraordinary in almost every way. The globulars, which are found in the halo of galaxies, are densely packed, holding a million stars in a ball only about 100 light-years across on average. They're old, dating back almost to the birth of the Milky Way. And according to research, could be extraordinarily good places to look for space-faring civilizations, says DiStefano.  

In the center of a rich cluster of galaxies located in the direction of the constellation of Coma Berenices, lies NGC 4874 galaxy surrounded by a swarm of star clusters. NGC 4874 is a giant elliptical galaxy, about ten times larger than the Milky Way, at the center of the Coma Galaxy Cluster (shown above). With its strong gravitational pull, it is able to hold onto more than 30,000 globular clusters of stars, more than any other galaxy that we know of, and even has a few dwarf galaxies in its grasp.

In this NASA/ESA Hubble Space Telescope image, NGC 4874 is the brightest object, located to the right of the frame and seen as a bright star-like core surrounded by a hazy halo. A few of the other galaxies of the cluster are also visible, looking like flying saucers dancing around NGC 4874. But the really remarkable feature of this image is the point-like objects around NGC 4874, revealed on a closer look: almost all of them are clusters of stars that belong to the galaxy. Each of these globular star clusters contains many hundreds of thousands of stars.

 

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Recently, astronomers discovered that a few of these point-like objects are not star clusters but ultra-compact dwarf galaxies, also under the gravitational influence of NGC 4874. Being only about 200 light-years across and mostly made up of old stars, these galaxies resemble brighter and larger versions of globular clusters. They are thought to be the cores of small elliptical galaxies that, due to the violent interactions with other galaxies in the cluster, lost their gas and surrounding stars.

This Hubble image also shows many more distant galaxies that do not belong to the cluster, seen as small smudges in the background. While the galaxies in the Coma Cluster are located about 350 million light-years away, these other objects are much farther out. Their light took several hundred million to billions of years to reach us.

This picture was created from optical and near-infrared exposures taken with the Wide Field Channel of Hubble's Advanced Camera for Surveys. The field of view is 3.3 arcminutes across.

The Daily Galaxy via NASA

Image credit Top of the Page: A team of astronomers has discovered enormous arms of hot gas in the Coma cluster of galaxies by using NASA's Chandra X-ray Observatory and ESA's XMM-Newton. These features, which span at least half a million light years, provide insight into how the Coma cluster has grown through mergers of smaller groups and clusters of galaxies to become one of the largest structures in the Universe held together by gravity. The composite image, with Chandra data in pink and optical data from the Sloan Digital Sky Survey appearing in white and blue, features these spectacular arms.

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