Featured Research

from universities, journals, and other organizations

Fermi Large Area Telescope Reveals Pulsing Gamma-ray Sources

Date:
September 9, 2009
Source:
Naval Research Laboratory
Summary:
Scientists have positively identified cosmic sources of gamma-ray emissions through the discovery of 16 pulsating neutron stars. Using the Large Area Telescope, the primary instrument on NASA's Fermi Gamma-ray Space Telescope satellite, the discoveries were made by conducting blind frequency searches on the sparse photon data provided by the LAT.

This image from the Fermi Gamma-ray Space Telescope displays newly found pulsars (circled in yellow) and millisecond pulsars (circled in magenta).
Credit: NASA/DoE/Fermi LAT Collaboration

Scientists at the Naval Research Laboratory (NRL) Space Science Division and a team of international researchers have positively identified cosmic sources of gamma-ray emissions through the discovery of 16 pulsating neutron stars.

Using the Large Area Telescope (LAT), the primary instrument on NASA's Fermi Gamma-ray Space Telescope satellite, the discoveries were made by conducting blind frequency searches on the sparse photon data provided by the LAT. The photons had energies between 20 Mega-electron-volts (MeVs) and 300 Giga-electron-volts (GeVs)— tens of millions to hundreds of billions of times more energetic than the photons we see with the human eye.

A second study, published at the same time, announced the detection of gamma-ray pulsations from eight Galactic millisecond pulsars (MSPs). Millisecond pulsars spin hundreds of times per second, but have magnetic fields 10,000 times lower than normal pulsars. These discoveries confirm that they, too, can produce powerful gamma-ray emissions.

"Fermi has truly unprecedented power for discovering and studying gamma ray pulsars," said Paul Ray astrophysicist, Naval Research Laboratory. "Since the demise of the Compton Gamma Ray Observatory a decade ago, we've wondered about the nature of unidentified gamma-ray sources it detected in our galaxy. These studies from Fermi lift the veil on many of them."

Pulsars are rapidly rotating, highly magnetized neutron stars that can emit radiation across the electromagnetic spectrum. Prior to the launch of Fermi, gamma-ray pulsations were only detected from pulsars previously discovered using radio or X-ray telescopes. Radio telescopes can detect pulsars only if one of the narrow radio beams is directly aimed at the telescope; otherwise the pulsar can remain hidden. The much broader gamma-ray beams allowed the new pulsars to be discovered as part of a comprehensive search for periodic gamma-ray emission using five months of Fermi LAT data and new computational techniques.

The newly discovered pulsars, with rotation periods that range from 48 to 444 milliseconds, help reveal the geometry of emission from rotation-powered pulsars and provide valuable information on population statistics, the energetics of pulsar wind nebulae and supernova remnants. A wide variety of astrophysical phenomena, such as pulsars, active galactic nuclei, gamma-ray bursts and some binary star systems are known to produce photons exceeding many MeVs.

"The Fermi LAT makes it possible for us to pinpoint neutron stars," said Eric Grove, astrophysicist and LAT Commissioner, NRL Space Science Division. "The combination of a very large collecting area, large field of view, and precision timing from an on-board Global Positioning System receiver enables the LAT to see sources that were far beyond the reach of previous gamma-ray telescopes."

Results of the two studies were published on July 2, 2009 in Science Express.

The LAT project is funded in the United States by NASA and developed in collaboration with the Department of Energy and by academic institutions and government agencies in France, Italy, Japan, and Sweden.


Story Source:

The above story is based on materials provided by Naval Research Laboratory. Note: Materials may be edited for content and length.


Journal References:

  1. Abdo et al. Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LAT. Science, 2009; 325 (5942): 840 DOI: 10.1126/science.1175558
  2. Abdo et al. A Population of Gamma-Ray Millisecond Pulsars Seen with the Fermi Large Area Telescope. Science, 2009; 325 (5942): 848 DOI: 10.1126/science.1176113

Cite This Page:

Naval Research Laboratory. "Fermi Large Area Telescope Reveals Pulsing Gamma-ray Sources." ScienceDaily. ScienceDaily, 9 September 2009. <www.sciencedaily.com/releases/2009/09/090909103006.htm>.
Naval Research Laboratory. (2009, September 9). Fermi Large Area Telescope Reveals Pulsing Gamma-ray Sources. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2009/09/090909103006.htm
Naval Research Laboratory. "Fermi Large Area Telescope Reveals Pulsing Gamma-ray Sources." ScienceDaily. www.sciencedaily.com/releases/2009/09/090909103006.htm (accessed April 23, 2014).

Share This



More Space & Time News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Nasa Gives You An Excuse to Post a Selfie on Earth Day

Nasa Gives You An Excuse to Post a Selfie on Earth Day

TheStreet (Apr. 22, 2014) NASA is inviting all social media users to take a selfie of themselves alongside nature and to post it to Twitter, Facebook, Flickr, Instagram, or Google Plus with the hashtag #globalselfie. NASA's goal is to crowd-source a collection of snapshots of the earth, ground-up, that will be used to create one "unique mosaic of the Blue Marble." This image will be available to all in May. Since this is probably one of the few times posting a selfie to Twitter won't be embarrassing, we suggest you give it a go for a good cause. Video provided by TheStreet
Powered by NewsLook.com
SpaceX's Dragon Spacecraft Captured by International Space Station

SpaceX's Dragon Spacecraft Captured by International Space Station

Reuters - US Online Video (Apr. 20, 2014) SpaceX's unmanned Dragon spacecraft makes a scheduled Easter Sunday rendezvous with the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Raw: Easter Morning Delivery for Space Station

Raw: Easter Morning Delivery for Space Station

AP (Apr. 20, 2014) Space station astronauts got a special Easter treat: a cargo ship full of supplies. The SpaceX company's cargo ship, Dragon, spent two days chasing the International Space Station following its launch from Cape Canaveral. (April 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins