Raphael Thys
IXPE spacecraft observing a blazar called Markarian 501
By Will Dunham
WASHINGTON (Reuters) - Most galaxies are built around humongous black holes. While many of these are comparatively docile, like the one at our Milky Way's center, some are fierce - guzzling surrounding material and unleashing huge and blazingly bright jets of high-energy particles far into space.
Using data from the recently deployed Imaging X-ray Polarimetry Explorer (IXPE) orbiting observatory, researchers on Wednesday offered an explanation for how these jets become so luminous: subatomic particles called electrons becoming energized by shock waves moving at supersonic speed away from the black hole.
The researchers studied an exotic object called a blazar at the center of a large elliptical galaxy named Markarian 501 located about 460 million light years away from Earth in the direction of the constellation Hercules. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).
Blazars are a subset of objects called quasars that are powered by supermassive black holes feeding on gas and other material at the center of galaxies and sending two jets of particles in opposite directions into space. Blazars are oriented such that one of their two jets from our vantage point on Earth is heading directly at us.
"Blazars are the most persistently bright objects in the observable universe. They are the most energetic. They have the biggest, scariest black holes. Everything that happens around them is so fascinating," said astronomer Yannis Liodakis of the Finnish Centre for Astronomy with ESO, lead author of the research published in the journal Nature.
Scientists have long sought to understand how the jets launched from blazars become so luminous and the behavior of the particles in them. The jets from this blazar extend to a distance of about a million light years.
IXPE, launched last December as a collaboration between the U.S. space agency NASA and the Italian Space Agency, measures the brightness and polarization - a property of light involving the orientation of the electromagnetic waves - of X-ray light from cosmic sources. Different phenomena, like shock waves or turbulence, present polarization "signatures."