An international team of astronomers has published the results of a study of the pulsar nebula MSH 15-52, better known as the Hand of God. The Chandra X-ray telescope participated in these observations.

Hand of God

In 2009, NASA published images of an amazing structure located 17,000 light years from Earth. At its center is the pulsar PSR B1509-58, a rapidly rotating neutron star with a diameter of only 20 km. It was formed as a result of the collapse of a giant star that occurred approximately 1,700 years ago.

The Hand of God pulsar nebula. The image is based on data from the Chandra X-ray telescope and ATCA.
Source: X-ray: NASA/CXC/Univ. of Hong Kong/S. Zhang et al.; Radio: ATNF/CSIRO/ATCA; H-alpha: UK STFC/Royal Observatory Edinburgh; Image Processing: NASA/CXC/SAO/N. Wolk

Despite its tiny size, the pulsar has a significant impact on its surroundings. It is responsible for the formation of a complex nebula that spans 150 light years. It resembles an X-ray image of a human hand with the palm and fingers extended. This is why the nebula got the nickname “Hand of God.”

Since then, astronomers have continued to study this object using Chandra. Now the Australia Telescope Compact Array (ATCA) has joined the observations. Its data was combined with data from Chandra, allowing for a new look at the exploding star and its surroundings.

Anatomy of a dead star

In the new image of the Hand of God, ATCA radio data is marked in red. In turn, the blue, orange, and yellow colors correspond to Chandra’s X-ray data. Hydrogen gas is shown in gold, and the area where X-ray and radio data intersect is shown in purple. 

Structure of the pulsar nebula Hand of God.
Source: X-ray: NASA/CXC/Univ. of Hong Kong/S. Zhang et al.; Radio: ATNF/CSIRO/ATCA; H-alpha: UK STFC/Royal Observatory Edinburgh; Image Processing: NASA/CXC/SAO/N. Wolk

The pulsar rotates nearly seven times per second and has a strong magnetic field, approximately 15 trillion times stronger than Earth’s. Rapid rotation and a strong magnetic field make B1509-58 one of the most powerful electromagnetic generators in the Milky Way. Its powerful wind, consisting of electrons and other particles, creates the nebula.

Radio data from ATCA show complex filaments aligned with the magnetic field of the nebula, shown by short straight white lines in the additional image. These filaments may be the result of the pulsar wind colliding with the remnants of a supernova.

Direction of magnetic field lines in the pulsar nebula Hand of God.
Source: X-ray: NASA/CXC/Univ. of Hong Kong/S. Zhang et al.; Radio: ATNF/CSIRO/ATCA; H-alpha: UK STFC/Royal Observatory Edinburgh; Image Processing: NASA/CXC/SAO/N. Wolk

By comparing radio and X-ray data, researchers identified key differences between the two types of light sources. In particular, some notable X-ray features, including the jet at the bottom of the image and the inner parts of the three “fingers” at the top, are not detected in radio waves. This indicates that high-energy particles are escaping from the shock wave near the pulsar and moving along magnetic field lines, creating fingers.

Radio data also show that the structure of RCW 89 differs from typical young supernova remnants. Most of the radio emission is uneven and corresponds exactly to the clusters of X-ray and optical emission. It also extends far beyond X-rays. All these characteristics confirm the idea that RCW 89 is colliding with a dense cloud of hydrogen located nearby.

However, not all questions were answered. One of the mysterious areas is the sharp boundary of X-ray radiation in the upper right corner of the image, which appears to be a shock wave from a supernova. Supernova shock waves usually glow brightly in the radio waves of young supernova remnants, so researchers are surprised by the absence of a radio signal at the X-ray boundary.

MSH 15–52 and RCW 89 exhibit many unique features not found in other young pulsar nebulae. However, many questions remain unanswered regarding the formation and evolution of these structures. According to scientists, further research is needed to better understand the complex interaction between the pulsar wind and the supernova remnant.

  • According to NASA