Astronomers are now equipped with a new pair of eyes in the sky.
As of mid-February, the new Imaging X-ray Polarimetry Explorer (IXPE) observation platform, orbiting Earth since late 2021, sent back its first exploration images to scientists on the ground—revealing new scenes of the cosmos with its X-ray eyes.
On Dec. 9, 2021, NASA, in conjunction with the Italian Space Agency (ISA), launched IXPE into orbit to examine space like never before. Aboard the Space X Falcon 9 rocket in Cape Canaveral, IXPE was sent into orbit 370 miles (600 km) over the earth’s equator. On Dec. 15, the imaging platform’s boom was successfully deployed, providing the distance needed to focus X-rays onto its detectors. The IXPE team then spent the next three weeks adjusting the telescope’s alignment, maneuvering, and pointing capabilities.
These system tests involved the use of two stellar calibrating targets: a black hole-powered galaxy core with jets shooting into space (known as 1ES 1959+650) and a pulsar (called SMC X-1), whose brightness allowed the team to observe where light fell on the IXPE’s polarization-sensitive detectors and make small adjustments.
Then, the IXPE trained its newly minted X-ray eyes on its first ever scientific imaging target: Cassiopeia A, the nebulous remains of a star that went supernova during the 17th century. This cosmic graveyard consists of a nebula some 10 light-years in diameter with a compact center believed to be a neutron star or black hole, which was first discovered by an older X-ray telescope, Chandra X-Ray Observatory, which was launched in 1999. The two observatories, IXPE and Chandra, feature different kinds of detectors that capture differing levels of angular resolution, or sharpness.
IXPE’s X-ray sensors are expected to uncover new insights about light polarization—measuring how X-ray light is oriented as it travels through space—and clues as to the environment where this light originates from. Researchers are currently working with the data produced to create a first ever X-ray polarization map of Cassiopeia A, which will offer insights as to how X-rays are produced within the object.
“IXPE’s future polarization images should unveil the mechanisms at the heart of this famous cosmic accelerator,” said Roger Romani, an IXPE co-investigator at Stanford University. “To fill in some of those details, we’ve developed a way to make IXPE’s measurements even more precise using machine learning techniques. We’re looking forward to what we’ll find as we analyze all the data.”
The NASA-ISA collaboration is in partnership with 12 other countries, while Ball Aerospace, headquartered in Broomfield, Colorado, manages the spacecraft’s operations.
