The Energy Sources of Ultraluminous Galaxies
Friday, November 27, 2009 - 12:21
in Astronomy & Space
(PhysOrg.com) -- Ultraluminous infrared galaxies ((ULIRGs) are galaxies whose luminosity exceeds that of a trillion suns; for comparison, the Milky Way galaxy has a typical (and much more modest) luminosity of only about ten billion suns. ULIRGs were discovered by an all-sky infrared survey satellite in the 1980's, and since then the origin(s) of their huge infrared emission has been widely debated. Extreme infrared activity is known to be associated with interacting galaxies, and optical imaging indeed shows that many ULIRGs are in collision, but this fact does not answer the question of what physical mechanism powers the luminosity. Might the same process be underway at a low level in our galaxy?