The universe is a spooky place. Besides the lurking Dark Matter and Dark Energy, even some of the things we can see look like they’d go bump in the night if space carried sound waves. Just in time for Halloween, NASA has released an image of one of the most eerie of all, a nebula nicknamed the “Hand of God” for its skeletal-looking fingers.
Properly named MSH 15-52, or PSR B1509-58, the nebula is appropriately the product of a dead star, more specifically a pulsar left behind by a supernova explosion 1,600 years ago. The neutron star left behind is spinning rapidly, releasing jets of matter and antimatter from its poles and a powerful wind.
The wind is sweeping up material thrown off during and before the supernova explosion. The pulsar sits at what pareidolia makes appear to our eyes to be the base of a palm, with the wind in one direction forming a forearm and in the other, glowing fingers.
For obvious reasons, MSH 15-52 has been a favorite for X-ray telescopes to image, but it’s not the creepy view that caused NASA to devote 17 days of the Imaging X-ray Polarimetry Explorer (IXPE)’s time to the nebula. This is the longest the IXPE has spent on any single object, and a considerable allocation of resources. This data has been combined with observations from the Chandra X-ray telescope to make the image above.
“The IXPE data gives us the first map of the magnetic field in the ‘hand’,” Professor Roger Romani of Stanford University, said in a statement. “The charged particles producing the X-rays travel along the magnetic field, determining the basic shape of the nebula, like the bones do in a person’s hand.”
As its name suggests, the IXPE doesn’t just collect X-rays, it captures their polarization, providing information that previous X-ray telescopes could not. Large parts of MSH 15-52 are unusually polarized, in some cases the maximum thought to be theoretically possible. That requires a magnetic field that is not only very powerful, but straight and uniform.
The Australia Telescope Compact Array previously used the polarization of radio waves to gain some insight into the nebula’s magnetic fields, but could not achieve anything like the precision X-rays offer.
“We’re all familiar with X-rays as a diagnostic medical tool for humans,” said co-author PhD student Josephine Wong. “Here we’re using X-rays in a different way, but they are again revealing information that is otherwise hidden from us.”
However, this magnetization varies greatly through the nebula. The brightest jet, which forms the hand’s “wrist” is initially not initially very polarized, which Romani, Wong, and colleagues attribute to tangled magnetic fields in a region of turbulence. To the extent the base of the wrist jet is polarized at all, it appears to be at an angle to the rest of the nebula, hard to detect from our line of sight.
As the jet moves away from the pulsar, the field lines straighten out and polarization increases. The researchers conclude that particles are being accelerated in the turbulent regions before flowing to where the field is straighter.
Since its 2021 launch, the IXPE has also spent time on other recently formed pulsars in our part of the galaxy, including the Crab and Vela nebulae, products of supernovae 1,000 and 11,000 years ago, respectively.
The IXPE’s results indicate similar magnetic fields around each, leading the team to conclude they’re a more common feature of wind nebulae than previously recognized.
And no, you’re not imagining it, the hand lacks a little finger – maybe something even more scary is out there lopping off space digits.
The study is open access in The Astrophysical Journal.