New data gathered by scientists at the Harvard-Smithsonian Center for Astrophysics using the Very Energetic Radiation Imaging Telescope Array System (VERITAS) in Arizona has given astronomers an inside look at a galaxy across the solar system with a black hole at its heart. The data stems from a flood of gamma rays that, after traveling for a time period that roughly equates to half the age of the universe, pierced the Earth's atmosphere and created a shower of light that hit the mirrors of VERITAS.
Gamma rays are made up of photons of light with extremely high energies, and these particular rays come from the galaxy PKS 1441+25, which is a rare type of galaxy called a blazar. At its core is a supermassive black hole, although the data from the VERITAS reveals that the source of the gamma rays is surprisingly far away from the black hole.
"We're looking down the barrel of this relativistic jet," Wystan Benbow, who participated in the research, said in a press release. "That's why we're able to see the gamma rays at all."
Additionally, the source of the gamma rays is larger than expected for a standard active galaxy, measuring a third of a light-year across.
"These jets tend to have clumps in them. It's possible that two of those clumps may have collided and that's what generated the burst of energy," said Matteo Cerruti, co-author of the study.
The fact that the researchers were able to measure the high-energy gamma rays at all is a feat in itself, given the fact that they tend to be absorbed at their source or on their journey to Earth. These findings will help scientists shed light on the phenomenon referred to as extragalactic background light (EBL), which is a faint haze of light that can be seen blanketing the universe. Data from EBL can be used to trace the history of the universe, and with the new gamma ray data, we can also determine the abundance of EBL.
The findings were published in the Dec. 15 issue of Astrophysical Journal Letters.
