NASA’s Chandra captures Pulsar with its X-ray speed camera

Pulsars spin fast neutron stars They can form when massive stars run out of fuel, collapse and explode. These explosions sometimes produce a “kick,” which is what prompted this pulsar to pass through the remnants of a supernova explosion. The inset shows a close-up view of this pulsar in Chandra’s X-rays.

To make this discovery, the researchers compared Chandra images of G292.0 + 1.8 taken in 2006 and 2016. Two complementary images show the change in the pulsar’s position over the course of 10 years. The displacement at the source location is negligible because the pulsar is about 20,000 light-years from Earth, but it traveled about 190 billion km during this period. The researchers were able to measure this by combining high-resolution Chandra images with micro-technology to verify the coordinates of the pulsar and other X-ray sources using precise locations from the Gaia satellite.

The team calculated that the pulsar was moving at least 1.4 million miles per hour from the center of the lower left of the supernova remnant. This velocity is about 30% higher than the previous estimate of the pulsar’s velocity based on an indirect method, by measuring the pulsar’s distance from the center of the explosion.

The newly determined velocity of the pulsar suggests that G292.0 + 1.8 and the pulsar may be much smaller than astronomers previously thought. The researchers estimate that G292.0 + 1.8 could have erupted about 2,000 years ago as seen from Earth, rather than 3,000 years ago as previously calculated. This new age estimate for G292.0 + 1.8 is based on extrapolating the pulsar’s location in time to coincide with the center of the explosion.

Several civilizations around the world were recording supernova explosions at the time, opening up the possibility of direct observation of G292.0 + 1.8. However, G292.0 + 1.8 is below the horizon for most Northern Hemisphere civilizations that you may have observed and there are no recorded examples of a supernova observed in the Southern Hemisphere in the direction of G292.0 + 1.8.

Close-up of the Chandra image center of the G292 + 1.8. The direction of motion of the pulsar (arrow) and the location of the blast center (green oval) are shown based on the motion of debris seen in the optical data. The position of the pulsar was extrapolated 3000 years ago and the triangle represents the uncertainty in the induction angle. The agreement of the site of the induction with the epicenter of the explosion gives an age of approximately 2,000 years to the pulsar and G292 + 1.8. The center of mass (intersection) of the X-ray elements detected in the debris (Si, S, Ar, Ca) faces the blast center with respect to the moving pulsar. The asymmetry in the debris in the upper right of the explosion pushed the pulsar to the lower left, while retaining its momentum. Credit: X-ray: NASA/CXC/SAO/L. Shi et al.; Optics: Palomar DSS2

In addition to learning more about G292.0 + 1.8’s age, the research team also studied how the pulsar’s supernova gave its powerful boost. There are two main possibilities, both of which mean that matter is not emanating from the supernova uniformly in all directions. One possibility is that neutrinos The outlet in the explosion is ejected asymmetrically from the explosion, the other is that the debris from the explosion is ejected asymmetrically. If matter had a preferred orientation, the pulsar would be pushed in the opposite direction due to a physical principle called conservation of momentum.

The amount of neutrino asymmetry required to account for the high speed in the latter result would be extreme, supporting the interpretation that the asymmetry in the debris from the explosion gave the pulsar its kick.

The energy transferred to the pulsar from this explosion was enormous. Although the pulsar is only about 10 miles in diameter, the pulsar is 500,000 times the mass of the Earth and moves 20 times faster than the speed of the Earth orbiting the sun.

The latest work by Xi Long and Paul Plucinksky (Astrophysics Center | Harvard & Smithsonian) on G292.0 + 1.8 was presented at the 240th Meeting of the American Astronomical Society in Pasadena, California. The results are also discussed in a paper accepted for publication in The Astrophysical Journal. The other authors of the article are Daniel Patno and Terence Gaetz, both of whom work at the Center for Astrophysics.

Reference: “Correct motion of pulsar J1124-5916 in the galactic supernova remnant G292.0 + 1.8” by Xi Long, Daniel J. Patnaude, Paul P. Plucinsky, and Terrance J. Gaetz, Accepted, Astrophysical Journal.
arXiv: 2205.07951

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