Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



TIME AND SPACE
Nearby pulsars shed light on the antimatter puzzle
by Staff Writers
Krakow, Poland (SPX) Nov 27, 2017


In cosmic rays there are more high-energy positrons than could be produced by pulsars in our vicinity: Geminga and PSR B0656+14. (Source: John Pretz)

There are too many high-energy positrons in the cosmic rays reaching the Earth. These positrons (particles that are antimatter equivalents of electrons) could be being produced by pulsars in our vicinity. The most recent measurements from the HAWC Observatory in Mexico have practically excluded this possibility, strengthening the competing and much more exotic hypothesis concerning the origin of the excess positrons.

Our planet is immersed in cosmic rays. The particles reaching the Earth from the depths of the Universe include positrons - antimatter equivalents of electrons. Astrophysicists have long been intrigued by why there are far more high-energy positrons in the cosmic rays than could be expected by current theoretical models. The latest attempt at an answer is the observations made by a team of several dozen researchers from the United States, Mexico, Germany and Poland, conducted using the recently activated High-Altitude Water Cherenkov Gamma-Ray Observatory (HAWC) detector.

The analysis of the measurements of the cosmic ray particles, which has just been published in the prestigious scientific journal Science, included the participation of a research group from the Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN) in Cracow, financed by the Polish National Science Centre OPUS grant.

"We know that high-energy particles of cosmic rays, travelling through our galaxy, quickly dissipate their energy by interacting with other radiation and magnetic fields. This is how particles of primary cosmic rays behave. Positrons are secondary, they come from interactions in which primary radiation is involved. We would therefore expect a similar dependence: a marked decrease in the number of high-energy positrons," explains Prof. Sabrina Casanova (IFJ PAN) and adds: "The reality is different. Satellite and terrestrial observatories record many more high-energy positrons than they should. Our aim was to check whether the source of the positron excess was astronomical objects in our vicinity, such as pulsars and their surrounding nebulae."

The HAWC Observatory is located on the slopes of the Mexican volcano Sierra Negra at an altitude of over 4100 metres above sea level. It houses 300 water tanks, surrounded by detectors sensitive to fleeting flashes of light, known as Cherenkov radiation. This radiation appears in the tank when a particle moving at a speed greater than the speed of light in water falls into it.

Each day at HAWC, in this manner, the presence of cosmic gamma photons with energies from 100 gigaelectronvolts (GeV) to 100 teraelectronvolts (TeV) is recorded.

These are energies even trillions of times greater than the energy of visible light photons and are over a dozen times greater than the energy of protons in the LHC accelerator. (It is worth noting that throughout the history of cosmic ray measurements, particles with energies of even up to 300 000 000 TeV have been recorded.)

"Detectors at the HAWC observatory record gamma radiation emitted, among others, by a certain population of electrons produced by pulsars and accelerated by them to huge energies. The basic question was: are there enough of these electrons for interactions with them to then produce the right number of positrons?" says Dr. Francisco Salesa Greus (IFJ PAN).

The experimental team conducted a very detailed analysis of the data collected for two relatively close pulsars known as Geminga and PSR B0656+14. The first is about 800 and the other over 900 light years distant from us. Both are among the strongest sources of cosmic rays in our region of the galaxy.

The analysis, covering 17 months of observation, showed that the radiation from both pulsars and their surrounding nebulae was indeed responsible for some of the positrons in the cosmic rays. However, contrary to the expectations of a large group of researchers, this contribution turned out to be several times too small to explain the actual number of TeV positrons.

"Since the involvement of close-by pulsars in the generation of high-energy positrons reaching us is so modest, other explanations become more and more likely. The most interesting is the hypothesis about the origin of excess positrons from the decay or annihilation of dark matter," comments Prof. Casanova.

If the hypothesis of the origin of positrons from the annihilation or decay of dark matter turns out, over time, to be true, the excess positrons in cosmic rays would be the first particles recorded by humans to be derived from the interaction of dark matter. Whether or not they really are, will be decided by future observations.

Research paper

TIME AND SPACE
Electron backscatter diffraction yields microstructure insights
Washington DC (SPX) Nov 17, 2017
High-efficiency electric motors with tailored speed-torques, determined by their magnetic components, are essential for sustainable, successful electric automobile drive concepts. Soft magnetic core engineering plays a key role in these motors, where the main soft magnetic materials used today are electrical steels. But for higher-frequency applications, soft magnetic composites (SMCs) are also ... read more

Related Links
The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
Understanding Time and Space


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

TIME AND SPACE
Does the Outer Space Treaty at 50 need a rethink

NASA to send critical science, instruments to Space Station

New motion sensors major step towards cheaper wearable technology

Can a magnetic sail slow down an interstellar probe

TIME AND SPACE
Flat-Earther's self-launch plan hits a snag

Aerojet Rocketdyne supports ULA Delta II launch of JPSS-1

Old Rivals India, China Nurture New Rivalry in Satellite Launch Business

NASA launches next-generation weather satellite

TIME AND SPACE
Gadgets for Mars

Ice shapes the landslide landscape on Mars

Previous evidence of water on Mars now identified as grainflows

Winds Blow Dust off the Solar Panels Improving Energy Levels

TIME AND SPACE
Nation 'leads world' in remote sensing technology

China plans for nuclear-powered interplanetary capacity by 2040

China plans first sea based launch by 2018

China's reusable spacecraft to be launched in 2020

TIME AND SPACE
Need to double number of operational satellites: ISRO chief

Space Launch plans UK industry tour

Astronaut meets volcano

European Space Week starts in Estonia

TIME AND SPACE
Booming life for 'PUBG' death-match computer game

3rd SES bids farewell to ANGELS satellite

New way to write magnetic info could pave the way for hardware neural networks

Borophene shines alone as 2-D plasmonic material

TIME AND SPACE
First known interstellar visitor is an 'oddball'

Lava or Not, Exoplanet 55 Cancri e Likely to have Atmosphere

Images of strange solar system visitor peel away some of the mystery

Familiar-Looking Messenger from Another Solar System

TIME AND SPACE
Pluto's hydrocarbon haze keeps dwarf planet colder than expected

Jupiter's Stunning Southern Hemisphere

Watching Jupiter's multiple pulsating X-ray Aurora

Help Nickname New Horizons' Next Flyby Target




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement