The Brightest Galaxies in the Universe!

Scientists call really bright galaxies ultraluminous galaxies (ULGs). Many of these ULGs are actually two galaxies colliding into each other in space! There are some ULGs that emit mostly infrared light. The Spitzer Space Telescope will be able to study this kind of ULG.

Interacting galaxies. Images from Kitt Peak National Observatory (left) and Hubble Space Telescope (right).
Scientists also want to study active galactic nuclei (AGN). These objects often appear bright in infrared, radio, and x-rays but very faint in visible light. Many scientists think that AGN might be powered by black holes.

What is the Spitzer Space Telescope? What is the Purpose of the Spitzer Space Telescope ? What Will the Spitzer Space Telescope Do? Building the Spitzer Space Telescope