Astronomers have used NASA’s Imaging X-ray Polarimetry Explorer, IXPE, to directly measure the magnetic fields around PSR J1101−6101, a pulsar inside what astronomers call the Lighthouse Nebula, NASA says in a July 9 release. NASA describes it as the first such measurement for this pulsar, which spins 16 times per second; the results appear in a paper in the Astrophysical Journal, also posted on arXiv. IXPE observed the nebula for nearly 18 days in June 2025.
The team studied two narrow X-ray offshoots, a long “filament” and a shorter “trail.” Researchers have suspected since 2008 that the highest-energy particles escape the pulsar’s bow shock and stream along the galaxy’s magnetic field lines to form the filament, NASA says. “If the magnetic field points along the filament, that confirms that the filament’s particles are flowing along the field,” said lead author Jack Dinsmore, a Stanford graduate student. The analysis confirmed with more than 99% confidence that the field does align with the flow, according to NASA.
The result also raised questions. “The high polarization degree we measured indicates lower turbulence than such models require,” said co-author Roger Romani of Stanford. In the trail, X-ray data pointed to a magnetic field parallel to the trail while radio observations pointed almost exactly perpendicular, which Niccolò Bucciantini of Italy’s National Institute for Astrophysics called “the first clear indication that particles of different energies occupy distinct regions within the system.”
IXPE flies as a joint mission of NASA and the Italian Space Agency, led by NASA’s Marshall Space Flight Center, NASA says.