NASA’s IXPE mission papers revolutionized our understanding of particle acceleration in black holes by using microquasar SS 433 as a case study to detect aligned magnetic fields in its jets.

The powerful gravitational fields of black holes can absorb matter from entire planets; They are often so powerful that they expel streams of particles traveling at the speed of light in formations known as jets. Scientists understand that these high-speed jets can accelerate these particles, called cosmic rays, but little is known about the process.

The latest findings by researchers using data from NASA’s Imaging X-ray Polarimetry Explorer (IXPE) spacecraft give scientists new clues about how particles accelerate in this extreme environment. The observations were made from a “microquasar”, a system containing a black hole absorbing material from a companion star.

More information about SS 433

The microquasar in question (Stevenson and Sandulik 433 or SS 433) is located at the center of the W50 supernova remnant in the constellation Eagle, about 18,000 light-years from Earth. SS 433’s powerful jets, which distort the remnant’s shape and earn it the nickname of the Manatee Nebula, reach speeds of more than 48,000 miles per second, about 26% of the speed of light. Discovered in the late 1970s, SS 433 is the first microquasar ever discovered.

IXPE’s three onboard telescopes measure a special property of X-ray light called polarization, which gives scientists information about the organization and alignment of electromagnetic waves at X-ray frequencies. X-ray polarization helps researchers understand physical processes occurring in extreme regions of our universe, such as the environment around black holes, and how particles are accelerated in these regions.

Groundbreaking discoveries and implications for the future

IXPE spent 18 days in April and May 2023 studying one such accelerator region in the eastern part of SS 433, where emissions are produced by energetic electrons spiraling in a magnetic field, a process called synchrotron radiation.

“The IXPE data show that the magnetic field near the acceleration region points in the direction of the jets,” said Philip Kaaret, an astrophysicist at NASA’s Marshall Space Flight Center in Huntsville, Ala., and principal investigator of the IXPE mission along with the lead author. . A new article about the finds at SS 433.

“The high level of polarization seen in IXPE indicates that the magnetic field is well-ordered and at least half of the field points in a single direction,” Kaaret said. said.

He said the discovery was unexpected. Researchers have long suggested that the interaction between the jet and the interstellar medium (the environment of gas and dust between stars) creates a shock that likely leads to irregular magnetic fields.

Kaaret said the data points to a new possibility that magnetic fields inside powerful jets can be “trapped” and stretched as they collide with interstellar matter, directly affecting their alignment in the particle acceleration region.

Since the 1980s, researchers have suggested that SS 433’s jets act as particle accelerators. In 2018, observers at the High Altitude Water Cherenkov Observatory in Puebla, Mexico tested the effect of jet acceleration, and scientists used NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Space Agency’s XMM-Newton observatories to map out the field. acceleration. .

As researchers continue to evaluate the results of IXPE and discover new targets in space, their data may also help determine whether the same mechanism is at work to align magnetic fields in streams ejected by a variety of phenomena, from supernova remnants to those emitted from black hole jets. debris. of stars exploding like blazars.