NASA's Swift, Fermi Probe Fireworks From a Flaring Gamma-Ray Star

“At times, this remarkable object has erupted with more than a hundred flares in as little as 20 minutes,” said Loredana Vetere, who is coordinating the Swift observations at Pennsylvania State University. “The most intense flares emitted more total energy than the sun does in 20 years.”

The object, which has long been known as an X-ray source, lies in the southern constellation Norma. During the past two years, astronomers have identified pulsing radio and X-ray signals from it. The object began a series of modest eruptions on Oct. 3, 2008, then settled down. It roared back to life Jan. 22 with an intense episode.

Because of the recent outbursts, astronomers will classify the object as a soft-gamma-ray repeater — only the sixth known. In 2004, a giant flare from another soft-gamma-ray repeater was so intense it measurably affected Earth's upper atmosphere from 50,000 light-years away.

Scientists think the source is a spinning neutron star, which is the superdense, city-sized remains of an exploded star. Although only about 12 miles across, a neutron star contains more mass than the sun. The object has been cataloged as SGR J1550-5418.

While neutron stars typically possess intense magnetic fields, a subgroup displays fields 1,000 times stronger. These so-called magnetars have the strongest magnetic fields of any known object in the universe. SGR J1550-5418, which rotates once every 2.07 seconds, holds the record for the fastest-spinning magnetar. Astronomers think magnetars power their flares by tapping into the tremendous energy of their magnetic fields.

“The ability of Fermi's gamma-ray burst monitor to resolve the fine structure within these events will help us better understand how magnetars unleash their energy,” said Chryssa Kouveliotou, an astrophysicist at NASA's Marshall Space Flight Center in Huntsville, Ala. The object has triggered the instrument more than 95 times since Jan. 22.

Using data from Swift's X-ray telescope, Jules Halpern at Columbia University captured the first “light echoes” ever seen from a soft-gamma-ray repeater. Images acquired when the latest flaring episode began show what appear to be expanding halos around the source. Multiple rings form as X-rays interact with dust clouds at different distances, with closer clouds producing larger rings. Both the rings and their apparent expansion are an illusion caused by the finite speed of light and the longer path the scattered light must travel.

“X-rays from the brightest bursts scatter off of dust clouds between us and the star,” Halpern said. “As a result, we don't really know the distance to this object as well as we would like. These images will help us make a more precise measurement and also determine the distance to the dust clouds.”

NASA's Wind satellite, the joint NASA-Japan Suzaku mission, and the European Space Agency's INTEGRAL satellite also have detected flares from SGR J1550-5418.

NASA's Goddard Space Flight Center in Greenbelt, Md., manages the Swift satellite. It is being operated in collaboration with partners in the U.S., the United Kingdom, Italy, Germany and Japan. NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics observatory developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden, and the U.S.

To see the related images, visit:
http://www.nasa.gov/mission_pages/swift/bursts/gammaray_fireworks.html
For more information about the Swift satellite, visit:
http://www.nasa.gov/swift
For more information about the Fermi mission, visit:
http://www.nasa.gov/fermi

Media Contact

J.D. Harrington EurekAlert!

All latest news from the category: Physics and Astronomy

This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.

innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors