Astr112 Photography Projects, Fall 2007

Galaxies (NGC 474 and NGC 470), Chantale Andree

NGC 474 and NGC 470 are different types of galaxies that are about 100 million light years from Earth in the constellation of the Fish Pisces. Galaxies are thought to have formed billions of years after the Big Bang through clumps of matter scattered throughout the universe. Some of the matter attracted into larger clumps and became visible galaxies. Astronomers believe that the different types of galaxies are caused by how quickly they were formed, and by collisions/interaction of the galaxies. The two galaxies in the picture are different types, and the shapes of the galaxies are caused by them interacting.

NGC 474 (galaxy on the left) is a shell galaxy that has an estimated linear size of 203,600 light years (including the shells). Shell galaxies get their name from the wide arcs that surround the galaxy. The ‘shells’ of NGC 474 can be faintly seen in the photograph. The shells in the galaxy are thought to be formed because of the interaction with NGC 470 -- NGC 470 is either pulling out the material or it is a ripple effect from the galaxies colliding. NGC 470 (the galaxy on right) is a lenticular galaxy that has a linear size of 58,100 light years. A lenticular galaxy is a galaxy that has a bright central bulge, but it does not seem to have any clearly defined arms. Lenticular galaxies get their name because of their resemblance of a lens when they are looked at edge-on.

References:
Lochner, Jim. "Formation of Galaxies."NASA Goddard Space Flight Center . <http://imagine.gsfc.nasa.gov/docs/teachers/galaxies/imagine/page22.htmll>.

"NGC 474 and NGC 470." Skyhound. <http://www.skyhound.com/sh/archive/nov/NGC_470.html>