The subject of the new image from the NASA/ESA Hubble Space Telescope is NGC 474, a gigantic elliptical galaxy located some 100 million light-years from Earth.
NGC 474 lies approximately 100 million light-years away in the constellation of Pisces.
This elliptical galaxy was discovered in 1784 by the German-born British astronomer Wilhelm Herschel.
Also known as LEDA 4801 and Arp 227, it forms an interacting pair with the spiral galaxy NGC 470.
NGC 474 has a diameter of 250,000 light-years — 2.5 times larger than our own Milky Way Galaxy.
“Along with its enormous size, NGC 474 has a series of complex layered shells that surround its spherical-shaped core,” Hubble astronomers said.
“The cause of these shells is unknown, but they may be the aftereffects of the giant galaxy absorbing one or more smaller galaxies.”
“In the same way a pebble creates ripples on a pond when dropped into the water, the absorbed galaxy creates waves that form the shells.”
“About 10% of elliptical galaxies have shell structures, but unlike the majority of elliptical galaxies, which are associated with galaxy clusters, shelled ellipticals usually lie in relatively empty space. It may be that they’ve cannibalized their neighbors.”
The color image of NGC 474 is made up of observations from Hubble’s Advanced Camera for Surveys (ACS), Wide Field and Planetary Camera 2 (WFPC2) and Wide Field Camera 3 (WFC3) instruments in the infrared and optical parts of the spectrum.
Several filters were used to sample various wavelengths. The color results from assigning different hues to each monochromatic image associated with an individual filter.
“The color blue represents visible blue light while the color orange represents near infrared light,” the researchers explained.
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