Featured Research

from universities, journals, and other organizations

Integral Disproves Dark Matter Origin For Mystery Radiation

Date:
August 2, 2009
Source:
European Space Agency
Summary:
A team of researchers working with data from ESA's Integral gamma-ray observatory has disproved theories that some form of dark matter explains mysterious radiation in the Milky Way.

Combining more than 4 years of observations, the inner Galaxy has been mapped in the 511 keV positron annihilation line with unprecedented detail as shown above using the SPI spectrometer. For the first time, positron annihilation is found to be asymmetric in the inner Galactic disk. Consistent with earlier findings, the annihilation emission is brightest around the Galactic centre. In the sky maps, the Galactic centre is at the origin and the Galactic disk runs along the equator.
Credit: ESA/ INTEGRAL/ MPE (G. Weidenspointner et al.)

A team of researchers working with data from ESA’s Integral gamma-ray observatory has disproved theories that some form of dark matter explains mysterious radiation in the Milky Way.

That this radiation exists has been known since the 1970s, and several theories have been proposed to explain it. Integral’s unprecedented spectral and spatial resolution showed that it strongly peaks towards the centre of the Galaxy, with an asymmetry along the Galactic disc.

Several researchers have invoked a variety of dark matter to explain Integral’s observations. Dark matter is thought to exist throughout the Universe – undetectable matter that differs from the normal material that makes up stars, planets and us. It is also believed to be present within and around the Milky Way, in the form of a halo.

The recent study has found that the ‘positrons’ fuelling the radiation are not produced from dark matter but from an entirely different, and much less mysterious, source: massive stars explode and leave behind radioactive elements that decay into lighter particles, including positrons, the antimatter counterparts of electrons.

The reasoning behind the original hypothesis was that positrons, being electrically charged, would be affected by magnetic fields and thus would not be able to travel far. As the radiation was observed in places that did not match the known distribution of stars, dark matter was invoked as an alternative for the origin of the positrons.

But the recent finding by a team of astronomers led by Richard Lingenfelter at the University of California at San Diego, proves otherwise. The astronomers show that the positrons formed by radioactive decay of elements left behind after explosions of massive stars are, in fact, able to travel great distances, with many leaving the thin Galactic disc.

Taking this into account, dark matter is no longer required to explain what Integral saw. A better understanding of how positrons behave has explained the mysterious radiation in our Galaxy.


Story Source:

The above story is based on materials provided by European Space Agency. Note: Materials may be edited for content and length.


Journal Reference:

  1. Lingenfelter, R.E., Higdon, J.C. Rothschild, R.E. Is There a Dark Matter Signal in the Galactic Positron Annihilation Radiation? Physical Review Letters, 2009; 103 (3): 031301 DOI: 10.1103/PhysRevLett.103.031301

Cite This Page:

European Space Agency. "Integral Disproves Dark Matter Origin For Mystery Radiation." ScienceDaily. ScienceDaily, 2 August 2009. <www.sciencedaily.com/releases/2009/08/090801122552.htm>.
European Space Agency. (2009, August 2). Integral Disproves Dark Matter Origin For Mystery Radiation. ScienceDaily. Retrieved August 28, 2014 from www.sciencedaily.com/releases/2009/08/090801122552.htm
European Space Agency. "Integral Disproves Dark Matter Origin For Mystery Radiation." ScienceDaily. www.sciencedaily.com/releases/2009/08/090801122552.htm (accessed August 28, 2014).

Share This




More Space & Time News

Thursday, August 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Experiment Tests Whether Universe Is Actually A Hologram

Experiment Tests Whether Universe Is Actually A Hologram

Newsy (Aug. 27, 2014) Researchers at Fermilab are using a device called "The Holometer" to test whether our universe is actually a 2-D hologram that just seems 3-D. Video provided by Newsy
Powered by NewsLook.com
SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com
Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Newsy (Aug. 21, 2014) Russian cosmonauts say they've found evidence of sea plankton on the International Space Station's windows. NASA is a little more skeptical. Video provided by Newsy
Powered by NewsLook.com
Space to Ground: Hello Georges

Space to Ground: Hello Georges

NASA (Aug. 18, 2014) Europe's ATV-5 delivers new science and the crew tests smart SPHERES. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
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