AstroTalk Episode February 2, 2017
Blazars In The Early Universe
3:10pm - 3:28pm
Blazars are very compact quasars (quasi-stellar radio sources) that are associated with presumed supermassive black holes. They are located at the center of active, giant elliptical galaxies. Blazars are among the most energetic phenomena in the universe. Scientists working with NASA's Fermi Gamma Ray Telescope have detected a blazar that breaks the record for the most distant blazar ever detected. The previous record holder sent its light toward Earth when the universe was only 2.1 Billion years old, but this newly discovered blazar breaks that record. Its light started coming toward Earth when the universe was only 1.4 Billion years old. In this galaxy, light and matter is pulled toward the central black hole, then gathers in an accretion disk, like cars gather on a road in a traffic jam. The matter heats up, and when the matter falls into toward the black hole, a small amount of it gathers and gets redirected into 2 particle jets, which shoot the matter out in opposite directions, along the central axis of rotation of the galaxy. When either of these jets is direct into the direction of the the Earth, then scientists can detect the jet. The energy output of the accretion disk has the output equivalent to 2 trillion times the energy output of our Sun. Scientists are surprised that a massive black hole such as this one, which is billions times the mass of our Sun, could have formed at such an early stage in our early universe. They are now trying to determine what caused the rapid development of this black hole. Scientists also detected 4 other blazars which appeared on a time scale when our universe was only 1.4 - 1.9 billion years old. Two of these blazars are powered by black holes that have the mass of more than 1 billion Suns. The detection of these blazars, at such an early stage in the universe, challenges some of the models that n ow describe how black holes formed and grow.