Powerful Gamma Rays from a Galaxy Far, Far Away Detected by VERITAS

In April 2015, a flood of powerful gamma rays slammed into the Earth's atmosphere. Now, scientists have taken a closer look at the data captured by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) to learn a bit more about the faraway galaxy where the gamma rays came from.

Gamma rays are photons of light with very high energies. These gamma rays came from a galaxy known as PKS 1441+25, which is a rare type of galaxy known as a blazar. At the center of this particular galaxy is a supermassive black hole that's surrounded by a disk of hot gas and dust.

As material from the disk swirls toward the supermassive black hole, some of it gets channeled into twin jets that blast outward like water from a fire hose. In fact, the material can travel close to the speed of light. One of these jets is aimed nearly in the direction of Earth, which gives us a view straight into the galaxy core.

"We're looking down the barrel of this relativistic jet," said Wystan Benbow, one of the researchers, in a news release. "That's why we're able to see the gamma rays at all."

One of the unknowns in blazar physics is the exact location of gamma-ray emissions. Using data from VERITAS, as well as the Fermi Gamma-Ray Space Telescope, the researchers found that the source of the gamma rays was actually surprisingly far from the galaxy's black hole. In addition, the region emitting gamma rays was larger than typically seen in an active galaxy.

"These jets have clumps in them," said Matteo Cerruti, co-author of the study. "It's possible that two of those clumps may have collided and that's what generated the burst of energy."

The findings reveal a bit more about this particular galaxy and show a bit more about the emission of gamma rays.

The findings are published in the Astrophysical Journal Letters.

Related Stories

Mars Clay May Have Formed Far More Recently Than Once Thought

Saturn's Moons Captured in Stunning View by NASA's Cassini Spacecraft

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).