The origin of these shells is unidentified, however astronomers theorize that they may be the aftereffects of the huge galaxy absorbing one or more smaller galaxies. Most elliptical galaxies are associated with galaxy clusters, however NGC 474 is in a fairly empty part of space. Only a much smaller sized spiral galaxy, NGC 470, is close-by and visible in the Digital Sky Survey image above.
The image was created utilizing information from Hubbles Advanced Camera for Surveys. Additional gap-filling information was provided by Hubbles Wide Field and Planetary Camera 2 and Wide Field Camera 3. The color blue represents visible blue light while the color orange represents near-infrared light that is just out of the range of human vision.
Hubble Space Telescope image of NGC 474, a gigantic elliptical galaxy NGC 474 located about 100 million light-years from Earth. Credit: NASA, ESA, and D. Carter (Liverpool John Moores University); Image processing: G. Kober (NASA Goddard/Catholic University of America).
This new NASA Hubble Space Telescope image captures the main area of the huge elliptical galaxy NGC 474. Located around 100 million light-years from Earth, NGC 474 spans around 250,000 light-years throughout– thats 2.5 times bigger than our own Milky Way galaxy!
Together with its gigantic size, NGC 474 has a series of complex layered shells that surround its spherical-shaped core. The origin of these shells is unidentified, however astronomers theorize that they might be the side effects of the giant galaxy absorbing several smaller galaxies. In a similar way to how a pebble creates ripples on a pond when dropped into the water, the absorbed galaxy produces waves that form the shells.
Most elliptical galaxies are associated with galaxy clusters, but NGC 474 is in a fairly empty part of area. Just a much smaller sized spiral galaxy, NGC 470, is visible and close-by in the Digital Sky Survey image above.
About 10% of elliptical galaxies have shell structures, but unlike the majority of elliptical galaxies, which are related to galaxy clusters, shelled ellipticals usually depend on reasonably void. It might be that theyve cannibalized their next-door neighbors.