Fermi Large Area Telescope reveals pulsing gamma-ray sources
September 9, 2009
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."
More information: Results of the two studies: "Detection of 16 gamma-ray pulsars through blind frequency searches using the Fermi LAT;" and "A population of gamma-ray millisecond pulsars seen with the Fermi Large Area Telescope" were published on July 2, 2009 in Science Express and may be found on the Internet at http://www.scienceexpress.org .
Source: Naval Research Laboratory (news : web)
Jul 02, 2009 |
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The is a great discovery. It seems to confirm that repulsive interactions between neutrons are a major energy source in the cosmos.
Again, congratulations!
Oliver K. Manuel
http://www.omatumr.com
Of course you do switch back and forth between neutron cores and iron cores. But either way its beta decay you are claiming.
So how does evidence for gamma rays in an accretion disc support you.
Ethelred
Death to short posts Tell Physorg what you think.
Yes, "pulsars generate a lot of power" . . . . from neutron repulsion.
They also have accretion disks, just like the proto-planetary disk that formed all of the planets orbiting the early Sun.
With kind regards,
Oliver K. Manuel
http://www.omatumr.com
Or perhaps its that rate of SPIN of a VERY massive object with a strong magnetic field that accelerates ions to near the speed of light plus creating electron positron pairs in the process. I call that a LOT of power. With no need to suppose a new source of energy that ISN'T a source of energy in the first place.
Even if neutron repel, totally unproven as NO ONE supports you on this, the energy would still come from somewhere else same as with any spring type system.
I pointed that out before and you consistently ignore it.
The source of power in the accretion disk is the vast momentum of the neutron star and mass conversion in the accretion disk from those electron-positron pairs.
Ethelred
I encourage you to read the new book "Heaven and Earth: global warming/the missing science" (Taylor Trade Tublishing, New York, 2009) by Professor Ian Plimer - Australia's best known geologist.
I bought a new copy of this 504 page soft-back book from Amazon.com for $14.93
With kind regards,
Oliver K. Manuel
http://www.omatumr.com
Save it for the meteorology discussions.
Ethelred
Brevity is for soulless twits.
Have you guys EVER read George Bernard Shaw?
A continuing campaign to convince Physorg that they do not want to emulate Youtube.
You will find the error in your statement that,
Read the book yourself and find out if you correctly described PROFESSOR IAN PLIMER as NO ONE.
Best wishes,
Oliver K. Manuel
http://www.omatumr.com
I did check to see if it was at the library in Anaheim. Even if it had been there I still wouldn't have checked it out UNLESS you can give a clue as to what and where is the part you think supports you. Perhaps if it was in the index I could check it without going through the whole thing.
I am quite willing to read the parts that are relevant but I simply am not going to buy it to do so.
However I did find a review of the book.
two lines to keep physog from botching it
http://scienceblo...imer.php
?utm_source=combinedfeed&utm_medium=rss
And it looks very much like he is using you as a source so that would not be independent. While you could construe that as a person supporting you it would not be EVIDENCE in support of you.
In other words it remains totally unproven and you are the only source.
Ethelred
Briefs, a lawyers guide to verbal excess
Death to short posts. Tell Physorg what you think.
FREELY AVAILABLE TO ANYONE WHO LOOKS
Repulsive forces between neutrons was discovered in the spring of 2000 - with the help of five graduate students - in the rest mass data of all known nuclei in an Advanced Nuclear Chemistry course (Chem 471) that I taught..
1. See: CRADLE OF THE NUCLIDES http://tinyurl.com/2otxps
2. Neutron repulsion confirmed as energy source, Journal of Fusion Energy 20 (2001) pages 197-201:http://tinyurl.com/mw7mhu
3. Other papers cited in: Fingerprints of a local supernova, in SPACE EXPLORATION RESEARCH (Nova Science Publishers, Inc., Hauppauge, NY, in press, 38 pp, 2009); ISBN: 978-1-60692-264-4
http://arxiv.org/pdf/0905.0684
Implications for SPACE SCIENCE, NUCLEAR SCIENCE & COSMOLOGY are here:
http://www.physor...489.html
With kind regards,
Oliver K. Manuel
You need confirmation from OTHERS not just yourself or one single person that is quoting you. A geologist and not a physicist at that.
Ethelred