IXPE is an X-ray astronomy mission launching in 2021 that is revolutionizing our understanding of cosmic phenomena such as blazars and supernova remnants. On December 9, astronomers and physicists marked two years of landmark X-ray science results from NASA's IXPE (Imaging X-ray Polar Explorer) mission.

The Imaging X-ray Polar Explorer (IXPE), launched in December 2021, is an important astronomical instrument orbiting the Earth and used to study X-ray radiation from cosmic phenomena such as quasars, quasars, and black holes. Its discovery played a key role in unraveling long-standing cosmic mysteries, such as the acceleration process of quasars and the activity of supernova remnants. Source: NASA

IXPE is a joint mission of NASA and the Italian Space Agency to study polarized X-ray light. Polarization is a property of light that helps reveal information about its origin, such as the geometry and inner workings of the powerful energy source that emits this light.

IXPE was launched on December 9, 2021, orbiting the Earth at an altitude of about 340 miles, studying X-ray radiation from powerful cosmic phenomena thousands to billions of light-years away from the Earth, including the remnants of supernova explosions such as quasars, blazars, and neutron stars, as well as high-energy particle streams ejected from near black holes at nearly the speed of light.

An animation of IXPE being deployed in space before embarking on an operation to scientifically study the universe. Source: NASA

"Adding X-ray polarization to our radio, infrared and optical polarization arsenal will be a game changer," said Alan Marscher, an astronomer at Boston University who led a research team using the IXPE findings to analyze supermassive black holes.

"We are all familiar with X-rays as medical diagnostic tools for humans," said Josephine Wong, a researcher at Stanford University. "Here, we use them in a different way, but again they reveal information that we cannot see."

Martin Weisskopf is an astrophysicist who led the development of IXPE and served as IXPE's principal investigator until his retirement from NASA in the spring of 2022.

"Without a doubt, IXPE has shown that X-ray polarimetry is very important and relevant for further understanding of these fascinating X-ray systems." -Martin Weisskopf, retired IXPE principal researcher

Scientists have long understood the basic principles of blazars such as Markarian501 and Markarian421. A quasar is a huge black hole that feeds on swirling matter and produces powerful jets of high-speed cosmic particles that fly in two directions perpendicular to the disk. But how are these particles accelerated to such high energies? IXPE data published in the journal Nature in November 2022 identified the culprit of Macharia 501 as shock waves inside the jet.

This illustration from NASA shows the structure of a black hole's jet inferred from recent observations of the blazar Markarian 421 by the Imaging X-ray Polar Explorer (IXPE). The jets are powered by an accretion disk, shown at the bottom of the image, which orbits the black hole and falls into it over time. A spiral magnetic field passes through the jet. IXPE's observations indicate that the X-rays must be produced by shocks inside matter rotating around a spiral magnetic field. The inset shows the impact front itself. X-rays are produced in the white region closest to the impact front, while optical and radio emissions must come from turbulent regions farther away from the impact. Source: NASA/Pablo Garcia

"We finally have all the pieces of the puzzle, and they add up to a very clear picture," said Yannis Liodakis, a NASA postdoctoral program researcher at NASA's Marshall Space Flight Center in Huntsville, Alabama.

IXPE also conducted unprecedented studies of three supernova remnants - Cassiopeia A, Tycho and SN1006 - to help scientists further understand the origins and processes of the magnetic fields surrounding these phenomena.

IXPE also sheds new light on the fundamental mechanics of our galaxy. According to research conducted by IXPE in early 2022, the supermassive black hole Sagittarius A* at the center of the Milky Way woke up about 200 years ago, swallowing gas and other cosmic garbage, triggering strong and short-lived X-ray flares. Combining data from IXPE, Chandra and the European Space Agency's XMM-Newton mission, the researchers determined that the event occurred around the early 19th century.

"We know that active galaxies and supermassive black holes can change on human timescales," said IXPE project scientist Steve Ehlert of NASA's Marshall Division. "IXPE is helping us better understand the timescales on which the black hole at the center of the Milky Way changes. We are eager to observe it further to determine which changes are typical and which are unique."

This new image of supernova remnant SN1006 combines data from NASA's Imaging X-ray Polarization Explorer and NASA's Chandra X-ray Observatory. The red, green and blue elements reflect the low-, medium- and high-energy X-rays detected by Chandra, respectively. Shown in purple in the upper left corner are IXPE data measuring the polarization of X-ray light, along with lines representing the outward motion of the remnant's magnetic field. Source: X-ray: NASA/CXC/SAO (Chandra); NASA/MSFC/Nanjing University/P.Zhou et al. (IXPE); IR: NASA/JPL/CalTech/Spitzer; ImageProcessing: NASA/CXC/SAO/J.Schmidt

IXPE also supports observations of unexpected cosmic events—such as the brightest pulse of intense radiation on record that suddenly swept through the solar system in October 2022.

Researchers say the pulse originated from a powerful gamma-ray burst that may not occur once in 10,000 years. IXPE supported data from NASA's Fermi Space Telescope and other imagers, helping to determine how the powerful emission was organized and confirming that Earth imagers observed the jet almost directly head-on.

Perhaps what excites space scientists most is that IXPE’s data is overturning traditional views on various types of high energy sources.

"In the past two years, we've seen a lot of polarized X-ray results that are so surprising that they throw theoretical models out the window," Ellert said.

"Seeing results we didn't expect leads to new questions, new theories. It's really exciting!" - Steve Ehlert, IXPE project scientist

The excitement continues among IXPE partners around the world. In June this year, the mission was officially extended by 20 months after its initial two-year flight, which means IXPE will continue to observe high-energy X-ray radiation throughout the universe until at least September 2025.

The new year will also mark the launch of the IXPE General Observer Program, which invites astrophysicists and other space scientists around the world to propose and participate in research using the IXPE telescope. From February 2024, 80% of IXPE time will be available to the wider scientific community.

Compiled source: ScitechDaily