Researchers studied an exotic object called a blazar at the center of a large elliptical galaxy.
November 24, 2022
WASHINGTON (Reuters) – Most galaxies are built around giant black holes. While many of them are comparatively docile, like that at the center of our Milky Way, some are fierce – devouring surrounding material and unleashing huge and blindingly bright jets of high-energy particles far into space.
Using data from the recently deployed orbiting Imaging X-ray Polarimetry Explorer (IXPE) observatory, researchers on Wednesday offered an explanation for how these jets get so bright: Subatomic particles called electrons are excited by shock waves that collide with Moving away from the black hole at supersonic speeds.
Researchers studied an exotic object called Blazar at the center of a large elliptical galaxy called Markarian 501, located about 460 million light-years from Earth toward the constellation of Hercules. A light year is the distance that light travels in one year, 5.9 trillion miles (9.5 trillion km).
Blazars are a subset of objects called quasars, powered by supermassive black holes that feed on gas and other material at the centers of galaxies and send two jets of particles into space in opposite directions. Blazars are oriented so that one of their two jets is heading straight for us from our vantage point on Earth.
“Blazars are the most consistently bright objects in the observable universe. They are the most energetic. They have the biggest, scariest black holes, lead author of the study published in the journal Nature.
Scientists have long tried to understand how the jets fired by blazars become so bright and how the particles they contain behave. The jets from this blazar stretch out to a distance of about a million light-years.
IXPE, launched last December in a collaboration between the US space agency NASA and the Italian space agency, measures the brightness and polarization – a light property that involves the alignment of electromagnetic waves – of X-ray light from cosmic sources. Various phenomena, such as shock waves or turbulence, show polarization “signatures”.
The researchers found evidence that particles in the jet become energized when struck by a shock wave propagating outwards within the stream and emit X-rays as they accelerate. A shock wave is produced when something travels faster than the speed of sound through a medium like air — like a supersonic jet does when it flies through Earth’s atmosphere — or a region of particles and magnetic fields called a plasma, as in this case .
“The light we see from the jets comes from electrons,” said astrophysicist and study co-author Alan Marscher of Boston University. “X-rays like the ones we see in Markarian 501 can only come from extremely energetic electrons.”
The driving force behind this drama is a black hole, an extraordinarily dense object with gravity so strong that not even light can escape. The supermassive black hole at the center of Markarian 501 has a mass roughly billion times that of the Sun. That’s about 200 times the mass of Sagittarius A*, the Milky Way’s supermassive black hole.
“Black holes are unique laboratories to study fundamental physics under extreme conditions that we can’t replicate on Earth,” said Liodakis.
“However, before we can use them as such, we need to understand all the physical processes that take place. For many years we observed high-energy light from these sources and had some theories about what the particles emitting that light would be like. The X-ray polarization capabilities of IXPE allowed us to test our theories directly for the first time,” said Liodakis.
‘; var i = Math.floor(r_text.length * Math.random()); document.write(r_text[i]);
#space #observatory #solve #mystery #giant #black #holes