Fermi Large Area Telescope reveals pulsing gamma-ray sources

Sep 09, 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 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 that can emit radiation across the . Prior to the launch of Fermi, gamma-ray pulsations were only detected from pulsars previously discovered using radio or X-ray 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 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 " 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)

Explore further: Chandra X-ray Observatory finds planet that makes star act deceptively old

add to favorites email to friend print save as pdf

Related Stories

Fermi telescope unveils a dozen new pulsars

Jan 06, 2009

(PhysOrg.com) -- NASA's Fermi Gamma-ray Space Telescope has discovered 12 new gamma-ray-only pulsars and has detected gamma-ray pulses from 18 others. The finds are transforming our understanding of how these ...

GLAST: The Challenge of Too Much New Data

May 22, 2007

The astrophysics community enthusiastically awaits the upcoming launch of the Gamma-ray Large Area Space Telescope (GLAST), the latest and most powerful gamma-ray telescope. But interpreting the huge amount of new data that ...

Large Area Telescope explores high-energy particles

Jul 28, 2009

(PhysOrg.com) -- NASA's Fermi Gamma-ray Space Telescope is making some exciting discoveries about cosmic rays and the Large Area Telescope aboard Fermi is the tool in this investigation. Scientists in the ...

Recommended for you

The entropy of black holes

Sep 12, 2014

Yesterday I talked about black hole thermodynamics, specifically how you can write the laws of thermodynamics as laws about black holes. Central to the idea of thermodynamics is the property of entropy, which c ...

Modified theory of dark matter

Sep 12, 2014

Dark matter is an aspect of the universe we still don't fully understand. We have lots of evidence pointing to its existence (as I outlined in a series of posts a while back), and the best evidence we have point ...

User comments : 9

Adjust slider to filter visible comments by rank

Display comments: newest first

omatumr
2 / 5 (4) Sep 09, 2009
CONGRATULATIONS!

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
Ethelred
5 / 5 (3) Sep 09, 2009
It confirms that pulsars generate a lot of power which is expected since they often have accretion disks. You are claiming beta decay in neutrons in iron cores. Not gamma rays in neutron stars.

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.
omatumr
2.3 / 5 (3) Sep 11, 2009
NEUTRON REPULSION IS THE SOURCE OF "POWER"

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




Ethelred
3 / 5 (2) Sep 12, 2009
Yes, "pulsars generate a lot of power" . . . . from neutron repulsion.

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
omatumr
2.3 / 5 (3) Sep 12, 2009
SEE: "HEAVEN and EARTH" by PROFESSOR IAN PLIMER

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
Ethelred
3.7 / 5 (3) Sep 13, 2009
And what does that book have to do with THIS discussion Oliver?

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.
omatumr
3.7 / 5 (3) Sep 13, 2009
IF YOU READ THE BOOK, "HEAVEN and EARTH," . . .

You will find the error in your statement that,

"Even if neutron repel, totally unproven as NO ONE supports you on this . . .


Read the book yourself and find out if you correctly described PROFESSOR IAN PLIMER as NO ONE.

And what does that book have to do with THIS discussion Oliver?

Ethelred


Best wishes,
Oliver K. Manuel
http://www.omatumr.com

Ethelred
3.7 / 5 (3) Sep 14, 2009
I am not buying that book on your say so.

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.
omatumr
2.3 / 5 (3) Sep 14, 2009
THE REPULSIVE FORCE BETWEEN NEUTRONS:
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
Ethelred
Sep 14, 2009
This comment has been removed by a moderator.
Ethelred
3.7 / 5 (3) Sep 15, 2009
Yes, and I read them all weeks ago. All the papers are yours. None have been confirmed by anyone else. The first one is evidence that large nuclei have more energy per nucleon than small nuclei and that is generally thought to be do more to the protons than the neutrons.

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