Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cosmic debris: Study looks inside the universe's most powerful explosions

10.04.2015

Finding sets the stage for discoveries from the next generation of neutrino telescopes

A new study provides an inside look at the most powerful explosions in the universe: gamma-ray bursts.

These rare explosions happen when extremely massive stars go supernova. The stars' strong magnetic fields channel most of the explosion's energy into two powerful plasma jets, one at each magnetic pole. The jets spray energetic particles for light-years in both directions, at close to light speed.

On Earth, we detect bits of the resulting debris as gamma rays. Researchers also suspect--but haven't been able to prove conclusively--that GRBs are the source of at least some of the cosmic rays and neutrinos that pepper our planet from space.

Now, physicists at The Ohio State University and their colleagues have begun to answer that question. By building some of the most detailed computer simulations ever made of a GRB jet's internal structure, they have been able to model particle production inside of it.

Their finding--that the non-uniform internal structure of the jets is key to determining the emission of the different kinds of astroparticles--appears online April 10 in the journal Nature Communications. The study also raises new questions that can be answered only by the next generation of neutrino telescopes.

Mauricio Bustamante, a Fellow of the Center for Cosmology and AstroParticle Physics at Ohio State, explained that the new computer model is a natural outgrowth of recent findings in astroparticle physics, such as the first confirmed cosmic neutrinos detected at the IceCube Neutrino Observatory at the South Pole in 2013.

"Previously, the details of the non-uniformity of the GRB jets were not too important in our models, and that was a totally valid assumption--up until IceCube saw the first cosmic neutrinos a couple of years ago," he said. "Now that we have seen them, we can start excluding some of our initial predictions, and we decided to go one step further and do this more complex analysis."

With partners at Penn State and the DESY national research center in Germany, Bustamante wrote new computer code to take into account the shock waves that are likely to occur within the jets. They simulated what would happen when blobs of plasma in the jets collided, and calculated the particle production in each region.

In their model, some regions of the jet are denser than others, and some plasma blobs travel faster than others.

Bustamante offered the analogy of the plasma jet as a long highway, albeit one where the cars are traveling at different speeds close to the speed of light.

"Everywhere on the highway there are fast-moving cars, but some of them will be fast sports cars, while others will be extra-fast Formula 1 racers. They will collide all over the highway, and when they do they will create debris. The debris always contains neutrinos, cosmic rays and gamma rays, but, depending on where the collisions occurred, one of these will typically dominate the emission," he said.

"If the cars collide close to the beginning of the highway, where the concentration of cars is higher, the debris will be mostly neutrinos. As they race along the highway, the concentration of cars goes down, and so when a collision occurs halfway through the length of the highway, the debris will be mostly cosmic rays. Further down the road, the concentration is even lower, and the gamma rays that we observe at Earth are produced in the collisions at this stage."

The amount of debris that reaches Earth depends on how energetic the star is and how far away it is.

One implication of the model is that the rate of neutrino production in GRBs might be lower than previously thought, so only a minimal number--say, 10 percent--of neutrinos detected on Earth are likely to come from GRBs. The density of neutrinos that reach Earth is called the neutrino flux, and the model predicts that the likely neutrino flux from GRBs is below the threshold of detection for today's neutrino telescopes.

"We expect that the next generation of neutrino telescopes, such as IceCube-Gen-2, will be sensitive to this minimal flux that we're predicting," Bustamante said. Then astrophysicists can use the model to refine notions of GRB internal structure and better understand the sources of cosmic particles detected on Earth.

Co-authors on the paper were Philipp Baerwald and Kohta Murase of the Institute for Gravitation and the Cosmos at Penn State and Walter Winter of DESY in Germany.

This work was funded by NASA, the German Research Foundation, and the U.S. National Science Foundation.

Contact: Mauricio Bustamante, (614) 292-0734; Bustamanteramirez.1@osu.edu

Written by Pam Frost Gorder, (614) 292-9475; Gorder.1@osu.edu

Media Contact

Pam Frost Gorder
Gorder.1@osu.edu
614-292-9475

 @osuresearch

http://news.osu.edu 

Pam Frost Gorder | EurekAlert!

More articles from Physics and Astronomy:

nachricht Water without windows: Capturing water vapor inside an electron microscope
13.12.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University

nachricht Columbia engineers create artificial graphene in a nanofabricated semiconductor structure
13.12.2017 | Columbia University School of Engineering and Applied Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

A whole-body approach to understanding chemosensory cells

13.12.2017 | Health and Medicine

Water without windows: Capturing water vapor inside an electron microscope

13.12.2017 | Physics and Astronomy

Cellular Self-Digestion Process Triggers Autoimmune Disease

13.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>