Astronomers have announced the discovery of a rare gamma ray emanating from an ancient galactic nucleus more than 12 billion light years away.
Only a small fraction of the galaxies in the cylinder can emit gamma rays. These high-energy photons are believed to originate from the vicinity of the supermassive black hole that resides in the center of the galaxy. When this happens, they are called active galaxies.
Astronomers estimate that less than 1% of active galaxies emit gamma rays towards Earth. The nucleus of these rare galaxies was then called Blazar. It is one of the most powerful sources of radiation in the universe.
Blazar is of two types: planar spectral quasars (FSRQ) and BL Lacertae objects (BL Lac). While the FSRQs are the relatively young galaxy nuclei with a lot of dust surrounding the black hole, the BL Lac objects are the FSRQs that evolved after consuming large amounts of matter to power the black hole. Lead author of the article Vaidehi Paliya from the German Research Institute DESY compared FSRQ to a new adult, while BL Lac represents the elderly.
The most remote and oldest BL Lake ever to be discovered is located about 11.3 billion light years from us. This means that when the gamma ray launch took place, our universe was only about 2.5 billion years after the Big Bang.
However, in a study recently published in Astrophysical Journal Letters, Paliya and his colleagues say the record was broken by a newly discovered BL Lac named 4FGL J1219. 0 + 3653. It is 12.1 billion light years from us and releases gamma beams at the age of 1.7 years. By comparison, the oldest known FSRQ occurred about a billion years after the Big Bang.
This discovery calls into question the current hypothesis that BL Lac is the last stage in the evolution of the FSRQ, prompting astronomers to reconsider the evolution of Blazar as well as the active galaxies.