Astronomers have unveiled unprecedented detail of the pulsar wind nebula MSH 15-52 through new, high-resolution radio observations. These findings, published on August 20, 2025, in The Astrophysical Journal, offer fresh insights into the complex structure of this celestial object, famously known as the "Cosmic Hand" or "Hand of God." The nebula is powered by the pulsar PSR B1509-58, a rapidly spinning neutron star approximately 12 miles in diameter that rotates nearly seven times per second.
The pulsar's immense power propels a wind of charged particles that sculpts the surrounding nebula, which spans an astonishing 150 light-years. Utilizing the Australia Telescope Compact Array (ATCA) with a resolution of 2 arcseconds, researchers mapped MSH 15-52 in radio wavelengths. These new radio maps reveal intricate filamentary structures, many of which are aligned with the nebula's magnetic fields. These delicate filaments are believed to form as the pulsar's wind collides with the debris from the supernova that created it.
A key revelation from these observations is the discrepancy between radio and X-ray emissions. Several prominent X-ray features, including a jet emanating from the pulsar and the nebula's distinctive "fingers," do not have corresponding radio signals. Astronomers theorize that this indicates the escape of highly energetic particles along magnetic field lines, a phenomenon likened to the sonic boom generated by supersonic aircraft.
The associated supernova remnant, RCW 89, also presents intriguing characteristics. Its radio emissions appear as patchy structures that closely align with clumps observed in X-ray and optical light, suggesting an interaction with a dense cloud of hydrogen gas. However, a sharp X-ray boundary, previously interpreted as the supernova's blast wave, lacks any radio emission, challenging existing models of young supernova remnants.
These findings enhance our comprehension of cosmic structures and the extreme environments in which they form. The detailed radio mapping provides a crucial piece in understanding how pulsars influence their surroundings and how energetic particles propagate through the cosmos, prompting further investigation into these complex processes.