An international team of astrophysicists, using data from the X-ray Polarimetry Explorer (IXPE) Space Telescope, has published new findings on the blazar called Markarian 421, an active galactic nucleus and a powerful gamma-ray source located in the constellation Ursa Major, approximately 400 million light years from Earth. The study, which states the IXPE team's findings on Markarian 421, was published in the latest issue of “Nature Astronomy”, with Professor Luca Baldini of the University of Pisa among the authors.
The structure of a black hole jet as deduced from recent observations of the blazar Markarian 421 with the Imaging X-ray Polarimetry Explorer (IXPE). Credits: NASA/Pablo Garcia.
"Despite decades of study, scientists still do not fully understand the physical processes that determine the dynamics and the emission of the relativistic jets ejected by blazars," says Luca Baldini. "Furthermore, the IXPE’s revolutionary ability to “measure the polarisation of X-rays", i.e., the direction of oscillation of their electric field, gives astronomers unprecedented insight into these objects, their geometry and the origin of their emissions.
The satellite IXPE, with three space telescopes, has been in orbit since 2021. It is the result of a collaboration between NASA and the Italian Space Agency with partners and scientific collaborators in 12 countries, including the University of Pisa in synergy with the Pisa Section of the National Institute of Nuclear Physics. There are three detector units on board, which have been designed, integrated and qualified in Pisa by a working group led by Professor Luca Baldini, who involved students from the Department of Physics and the School of Engineering of the University of Pisa.