A blazar is a galaxy whose central supermassive black hole emits a powerful jet of high velocity particles aimed almost directly at Earth. Astronomers have measured and successfully modelled the very high energy gamma ray emission from a blazar known as 1ES 1741+196 using VERITAS, the Very Energetic Radiation Imaging Telescope Array System.
In April 2015, after travelling for about half the age of the universe, a flood of powerful gamma rays from a distant galaxy slammed into Earth’s atmosphere. Observations of PKS 1441+25, a rare type of galaxy called a blazar, provide a look into the environment near a supermassive black hole at the galaxy’s centre and offer a glimpse into the state of the cosmos 7 billion years ago.
Astronomers using data from NASA’s Fermi Gamma-ray Space Telescope have detected hints of periodic changes in the brightness of a so-called “active” galaxy, whose emissions are powered by a supersized black hole. If confirmed, the discovery would mark the first years-long cyclic gamma-ray emission ever detected from any galaxy, which could provide new insights into physical processes near the black hole.