The mysterious ghost hand discovered by NASA’s X-ray telescopes

NASAIXPE’s Chandra and IXPE telescopes unveil the magnetic “bones” of the “hand” shape. Pulsar The Wind Nebula, MSH 15-52, provides pioneering insights into X-ray polarization and magnetic field dynamics.

• Chandra and IXPE data were used to examine the pulsating wind nebula known as MSH 15-52.
• Pulsar wind nebulae are clouds of energetic particles hurtling away from dead and collapsing stars.
• The MSH 15-52 is known for its shape that resembles a human hand.
• IXPE observed it for about 17 days of observing time, the longest look at a single object yet for this mission.

The marvel of pulsars

Rotating neutron stars with strong magnetic fields, or pulsars, act as laboratories for extreme physics, providing high-energy conditions that cannot be replicated on Earth. Young pulsars can create jets of matter and antimatter that move away from the pulsar’s poles, along with intense winds, forming a “pulsar wind nebula.”

Discovery of the “hand in space”

In 2001, NASA’s Chandra X-ray Observatory first observed the pulsar PSR B1509-58 and revealed that the pulsar’s wind nebula (referred to as MSH 15-52) resembled a human hand. The pulsar is located at the base of the nebula’s “palm.” Now Chandra’s data on MSH 15-52 have been combined with data from NASA’s newest X-ray telescope, the X-ray Polarimetry Explorer (IXPE), to reveal the “bones” of this remarkable structure’s magnetic field. IXPE stared at MSH 15-52 for 17 days, the longest it has looked at any object since its December 2021 launch.

This is a view of MSH 15-52 from the Chandra X-ray observation. It does not include the IXPE X-ray and infrared observations included in the composite image at the top of the article. Image credit: X-ray: NASA/CXC/Stanford University./R. Roman et al. (Chandra); Image processing: NASA/CXC/SAO/J. Schmidt

Interpretation of the composite image

In a new composite image, Chandra data appears in orange (low-energy X-rays), green, and blue (high-energy X-rays), while diffuse purple represents IXPE observations. The pulsar is located in the bright region at the base of the palm and the fingers point toward low-energy X-ray clouds in the surrounding remnants of the supernova that formed the pulsar. The image also includes infrared data from the Red and Blue Data Release 2 Dark Energy Plane Survey (DECaPS2).

The first medical x-ray performed by Wilhelm Röntgen of the hand of his wife Anna Bertha Ludwig. Credit: Wilhelm Roentgen

X-ray polarization and magnetic map

IXPE data provide the first map of the magnetic field in a ‘hand’. It reveals information about the direction of the X-ray electric field determined by the magnetic field of the X-ray source. This is called “X-ray polarization”.

An additional X-ray image (below) shows a map of the magnetic field at MSH 15-52. In this image, short straight lines represent IXPE polarization measurements, mapping the direction of the local magnetic field. Orange “bars” indicate the most accurate measurements, followed by cyan and blue bars with less precise measurements. Complex field lines trace the “wrist,” “palm,” and “fingers” of the hand, perhaps helping to identify extended finger-like structures.

Map of the magnetic field at MSH 15-52. The lines represent IXPE polarization measurements, mapping the direction of the local magnetic field. The length of the bars indicates the amount of polarization. Image credit: X-ray: NASA/CXC/Stanford University./R. Roman et al. (Chandra); NASA/MSFC (IXPE); Infrared: NASA/JPL-Caltech/DECaPS; Image processing: NASA/CXC/SAO/J. Schmidt

Magnetic field and polarization

The amount of polarization, indicated by the length of the band, is remarkably high, reaching the maximum expected from theoretical work. To achieve this strength, the magnetic field must be very straight and uniform, which means there is little turbulence in those regions of the pulsar wind nebula.

One particularly interesting feature of MSH 15-52 is the bright X-ray jet directed from the pulsar into the “wrist” at the bottom of the image. The new IXPE data reveal that the polarization at the beginning of the flow is low, likely because this is a turbulent region with complex, entangled magnetic fields associated with the generation of high-energy particles. By the end of the jet, the magnetic field lines appear to straighten out and become more regular, causing the polarization to become much greater.

A paper describing these findings has been published by Roger Romani of Stanford University and his collaborators the Astrophysical Journal On October 23, 2023.

Reference: “The cosmic polarizing hand: IXPE observations of PSR B1509−58/MSH 15−52” by Roger W. Romani, Josephine Wong, Nicola Di Lalla, Nicola Omudi, Fei Shih, C.-Y. Ng, Riccardo Ferrazzoli, Alessandro De Marco, Niccolò Pocciantini, Maura Biglia, Patrick Slane, Martin C. Weiskopf, Simon Johnston, Marta Burgay, Ding Wei, Yijun Yang, Shuming Zhang, Lucio A. Antonelli, Matteo Bacchetti, Luca Baldini, Wayne H. Baumgartner, Ronaldo Bellazzini, Stefano Bianchi, Stephen D. Bongiorno, Raffaella Bonino, Alessandro Brez, Fiamma Capitano, Simone Castellano, Elisabetta Cavazotti, Shen Ting Chen, Niccolò Cebrario, Stefano Ciprini, Enrico Costa, Alessandra De Rosa, Ettore del Monte, Laura De Gesu, Immacolata Donnarumma, Viktor Doroshenko, Michal Dovciak , Steven R. Eilert, Teruaki Enotto, Yuri Evangelista, Sergio Fabiani, Javier A. Garcia, Shoichi Junji, Kiyoshi Hayashida, Jeremy Hill, Wataru Iwakiri, Ioannis Leoudakis, Philip Kart, Vladimir Karas, Dawun E. Kim, Takao Kitaguchi, Jeffrey J. Kolodziejczak, Henryk Krawczynski, Fabio LaMonaca, Luca Latronico, Grzegorz Madejski, Simon Maldera, Alberto Manfreda, Frédéric Marin, Andrea Marinucci, Alan B. Marcher, Herman L. Marshall, Francesco Massaro, Giorgio Matte, Riccardo Medi, Ikuyuki Mitsuishi, Tsunefumi Mizuno, Fabio Moelleri, Michela Negro, Stephen L. Udell, Chiara Oppedisano, Luigi Pazziani, Alessandro Papetto , George G. Pavlov, Matteo Perry, Melissa Pace Rollins, Pierre-Olivier Petrucci, Andrea Possenti, Juri Potanin, Simonetta Boccetti, Brian D. Ramsey, John Rankin, Ajay Ratheesh, Oliver J. Roberts, Carmelo Sgro, Paolo Sovita, Gloria Spandri, Douglas A. Swartz, Toru Tamagawa, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Allen F. Tennant, Nicholas E. Thomas, Francesco Tompesi, Alessio Troa, Sergey Tsygankov, Roberto Torola, Jaco Fink, Kenoah Wu and Sylvia Zane, October 23, 2023, Astrophysical Journal.
doi: 10.3847/1538-4357/acfa02

IXPE is a collaboration between NASA and the Italian Space Agency with scientific partners and collaborators in 12 countries. IXPE is headed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. Ball Aerospace, based in Broomfield, Colorado, manages spacecraft operations in collaboration with the University of Colorado Laboratory for Atmospheric and Space Physics in Boulder.

NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.