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Fermi telescope finds farthest blazars yet

Black-hole-powered galaxies called blazars are the most common sources detected by NASA's Fermi. As matter falls toward the supermassive black hole at the galaxy's center, some of it is accelerated outward at nearly the speed of light along jets pointed in opposite directions. When one of the jets happens to be aimed in the direction of Earth, as illustrated here, the galaxy appears especially bright and is classified as a blazar. Credit: M. Weiss/CfA

NASA’s Fermi Gamma-ray Space Telescope has located the farthest blazars yet pinpointed in the universe.  Blazars are galaxies that emit powerful gamma rays from the supermassive black holes at their centers.

According to Phys.Org, the light arriving from the most distant blazar dates from when the universe was only about 1.4 billion years old – almost ten percent of its current age.

“Despite their youth, these far-flung blazars host some of the most massive black holes known,” Roopesh Ojha of NASA’s Goddard Space Flight Center said. “That they developed so early in cosmic history challenges current ideas of how supermassive black holes form and grow, and we want to find more of these objects to help us better understand the process.”

Fermi’s Large Area Telescope (LAT) searches the sky for gamma radiation, and about half of the gamma-ray sources it finds are blazars.

Astronomers think a blazar’s intense emissions are created when some of the matter falling toward a monster black hole is accelerated into space at speeds approaching the speed of light.  The black hole produces two jets of high-energy particles that shoot out from opposite sides of the black hole.  When one jet happens to face Earth’s observatories, the output can be detected in every light spectrum, including the highest-energy light – gamma rays.

The newly detected blazars date from when the universe was between 1.4 and 1.9 billion years old.

“Once we found these sources, we collected all the available multiwavelength data on them and derived properties like the black hole mass, the accretion disk luminosity, and the jet power,” Vaidehi Paliya of Clemson University said.

Two of the blazars have black holes of at least a billion solar masses.  All of the ancient blazars emit over two trillion times the energy output of the Sun.

“The main question now is how these huge black holes could have formed in such a young universe,” Dario Gasparrini of the Italian Space Agency said.  “We don’t know what mechanisms triggered their rapid development.”

“We think Fermi has detected just the tip of the iceberg, the first examples of a galaxy population that previously has not been detected in gamma rays,” Marco Ajello of Clemson University said.

The study has been submitted to The Astrophysical Journal Letters.

Kathy Fey

Kathy Fey

Staff Writer
Kathy Fey is a freelance writer with a creative writing degree from Mount Holyoke College. She is an active blogger and erstwhile facilitator of science and engineering programs for children.
About Kathy Fey (605 Articles)
Kathy Fey is a freelance writer with a creative writing degree from Mount Holyoke College. She is an active blogger and erstwhile facilitator of science and engineering programs for children.