                        Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                               2024 November 7

                          Shell Galaxies in Pisces
                  Image Credit & Copyright: George Williams

   Explanation: This spectacular intergalactic skyscape features Arp 227,
   a curious system of galaxies from the 1966 Atlas of Peculiar Galaxies.
   Some 100 million light-years distant within the boundaries of the
   constellation Pisces, Arp 227 consists of the two galaxies prominent
   above and left of center, the shell galaxy NGC 474 and its blue,
   spiral-armed neighbor NGC 470. The readily apparent shells and star
   streams of NGC 474 are likely tidal features originating from the
   accretion of another smaller galaxy during close gravitational
   encounters that began over a billion years ago. The large galaxy on the
   bottom righthand side of the deep image, NGC 467, appears to be
   surrounded by faint shells and streams too, evidence of another merging
   galaxy system. Intriguing background galaxies are scattered around the
   field that also includes spiky foreground stars. Of course, those stars
   lie well within our own Milky Way Galaxy. The telescopic field of view
   spans 25 arc minutes or just under 1/2 degree on the sky.

                     Tomorrow's picture: pixels in space
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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