Categories: Physics

New Pulsar “Clocks” Will Aid Gravitational Wave Detection

This illustration shows a pulsar’s magnetic field (blue) creates narrow beams of radiation (magenta). Image credit: NASA

How do you detect a ripple in space-time itself? Well, you need hundreds of precision clocks distributed throughout the galaxy, and the Fermi gamma ray telescope has given astronomers a new way to find them.

The “clocks” in question are actually millisecond pulsars – city-sized, sun-massed stars of ultradense matter that spin hundreds of times per second. Due to their powerful magnetic fields, pulsars emit most of their radiation in tightly focused beams, much like a lighthouse. Each spin of the pulsar corresponds to a “pulse” of radiation detectable from Earth. The rate at which millisecond pulsars pulse is extremely stable, so they serve as some of the most reliable clocks in the universe.

Astronomers watch for the slightest variations in the timing of millisecond pulsars which might suggest that space-time near the pulsar is being distorted by the passage of a gravitational wave. The problem is, to make a reliable measurement requires hundreds of pulsars, and until recently they have been extremely difficult to find.

“We’ve probably found far less than one percent of the millisecond pulsars in the Milky Way Galaxy,” said Scott Ransom of the National Radio Astronomy Observatory (NRAO).

Data from the Fermi gamma-ray space telescope, which started collecting data in 2008, have changed the way millisecond pulsars are detected. The Fermi telescope has identified hundreds of gamma-ray sources in the Milky Way. Gamma rays are high-energy photons, and they are produced near exotic objects, including millisecond pulsars.

“The data from Fermi were like a buried-treasure map,” Ransom said. “Using our radio telescopes to study the objects located by Fermi, we found 17 millisecond pulsars in three months. Large-scale searches had taken 10-15 years to find that many.”

Ransom and collaborator Mallory Roberts of Eureka Scientific used the National Science Foundation’s Robert C. Byrd Green Bank Telescope (GBT) to find eight of the 17 new pulsars.

Right now astronomers have only barely enough millisecond pulsars to make a convincing gravitational wave detection, but with Fermi to help identify more pulsars, the odds of detecting these ripples in space-time are steadily increasing.

Ransom and Roberts announced their discoveries today at the American Astronomical Society’s meeting in Washington, DC.

(NRAO Press Release)

Ryan Anderson

Ryan Anderson is a graduate student at Cornell University. He has a background in astronomy and physics, but now spends his days studying Mars. His research focuses on preparing for the upcoming Mars Science Laboratory mission by studying potential landing sites and shooting rocks with lasers.

Recent Posts

NASA is Building a Nuclear Reactor to Power Lunar and Martian Exploration!

NASA and the U.S. Dept. of Energy have come together to solicit design proposals for…

22 hours ago

InSight Peers Deep Below the Surface on Mars

The InSight lander has been on Mars, gathering data for a thousand days now, working…

2 days ago

Astronauts Took A Fly-around of the International Space Station. Here are Their Stunning Pictures

When astronauts left the International Space Station in early November to return home on the…

2 days ago

NASA Simulation Shows What Happens When Stars Get Too Close to Black Holes

What happens to a star when it strays too close to a monster black hole?…

3 days ago

The Parker Solar Probe is getting pelted by hypervelocity dust. Could they damage spacecraft?

There’s a pretty significant disadvantage to going really fast - if you get hit with…

3 days ago

The Decadal Survey is out! What new Missions and Telescopes are in the Works?

It’s that time again.  Once every ten years, the American astronomy community joins forces through…

3 days ago