Mysterious Gamma Rays Have Been Found in Galaxies Fueled by Feeding Black Holes.
Hundreds of previously undetected gamma-ray sources have been linked to blazars, active galaxies with a feeding supermassive black hole at their heart that fire energy jets towards Earth, according to a team of astronomers.
The study, which was published in The Astronomical Journal, tackles one of the most difficult problems in high-energy gamma-ray astronomy: finding low-energy equivalents to unknown gamma-ray sources.
The Fermi Gamma-ray Space Telescope (Fermi), which was launched in 2008 and monitors the sky in high-energy radiation from a low-Earth orbit, has discovered nearly a third of the objects observed so far.
When gas is trapped by the gravitational force of a supermassive black hole at the center of an active galaxy, known as an active galactic nucleus (AGN), a blazar is formed. This entity can have a mass billions of times that of the sun.
As the gas is eventually “fed” to the huge center object, it forms an accretion ring surrounding the black hole. Before the gas reaches the black hole’s event horizon, the point beyond which no light can escape, it produces so much electromagnetic radiation that AGNs are often brighter than the combined emissions of all the stars in the galaxy in which it resides.
When this incredibly intense jet, which includes material blasted across space at 99 percent the speed of light, is oriented such that it is pointed straight towards Earth, it is called a blazar.
“The term blazar simply refers to an active galaxy with a jet pointing toward Earth,” said Francis Halzen, a physics professor at the University of Wisconsin-Madison. “Of course, this means we’re smack dab in the middle of the black hole’s particle beam.” Blazars have been found as the most common source of gamma rays, leading astronomers to suspect that unidentified gamma-ray sources could also be from these dynamic galaxies with a central supermassive black hole busily eating material.
The challenge is that astronomers must examine candidates in visible light to fully comprehend this connection and determine the nature of these mysterious gamma-ray sources.
To do so, a group of experts lead by Dr.. from Mexico’s National Institute of Astrophysics This is a condensed version of the information.