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NASA's Fermi Satellite watches cannonball pulses accelerate through space – ScienceDaily



Astronomers found a pulsating winding through space of nearly 2.5 million miles per hour – so fast that it could drive the distance between Earth and Moon in just 6 minutes. The discovery was made using NASA's Fermi Gamma-ray Space Telescope and the National Science Foundation Karl G. Jansky's Very Large Array (VLA).

Pulsars are super-dense, fast-paced neutron stars left when a massive star explodes. This one, called PSR J0002 + 6216 (J0002 for short), sports a radio transmitting tail that points directly to the expanding junk of a new supernova explosion.

"Thanks to its narrow dart-like tail and a continuous viewing angle, we can trace this pulsar straight back to its birthplace," said Frank Schinzel, a researcher at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico. "Further study of this object helps us better understand how these explosions can" kick "neutron stars at such a high speed."

Schinzel, along with his colleagues Matthew Kerr at the US Naval Research Laboratory in Washington and NRAO researchers Dale Frail, Urvashi Rau and Sanjay Bhatnagar, presented the discovery at the High Energy Astrophysics Division meeting of the American Astronomical Society in Monterey, California. A paper describing the team's results has been submitted for publication in a future edition of The Astrophysical magazines.

Pulsar J0002 was discovered in 2017 by a citizenship project called Einstein @ Home, which uses time on the computers for volunteers to process Fermi gamma ray data. Thanks to the computer's processing time collectively in excess of 10,000 years, the project has so far identified 23 gamma-ray pulsars.

Located approximately 6,500 light-years away in the Cassiopeia constellation, J0002 spins 8.7 times per second, giving a pulse of gamma rays with each rotation.

The pulse is about 53 light-years away from the center of a supernova plant called CTB 1. The rapid movement through interstellar gas results in shock waves that produce the tail of magnetic energy and accelerated particles detected at radio wavelengths by the VLA. The tail extends over 13 light years and clearly points back to the center of CTB 1.

With the help of Fermi data and a technology called pulsar timing, the team could measure how quickly and in what direction the pulser moves over our point of view.

"The longer the dataset, the more powerful is the pulsar-time technology," says Kerr. "Fermi's beautiful 10-year dataset is essentially what made this measurement possible."

The result supports the idea that the pulsar was kicked in at high speed by the supernova responsible for CTB 1, which occurred about 10,000 years ago.

J0002 faster through space five times faster than the average pulsar, and faster than 99 percent of those with measured speeds. It will eventually escape from our galaxy.

First, supernova's expanding debris would have moved outwards faster than J0002, but over thousands of years, the shell's interstellar gas interaction gave a move that gradually suppressed this movement. At the same time, the pulsar, more like a cannonball, fought steadily through the remains and released it about 5000 years after the explosion.

Exactly how the pulsar was accelerated to such a high speed during the supernova explosion remains unclear, and further studies of J0002 help to shed the light on the process. A possible mechanism involves instabilities in the collapsing star forming a region of dense, slowly moving matter that survives long enough to serve as a "gravitational tug", accelerating the prominent neutron star against it.

The team plans further observations using the VLA, the National Science Foundation's Very Long Baseline Array (VLBA) and NASA's Chandra X-ray Observatory.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under the co-operation agreement of Associated Universities, Inc.

The Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland. Fermi was developed in collaboration with U.S. Department of Energy with major contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.


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