Exchanges of identity in deep space

September 07, 2017

Like in a nail-biting thriller full of escapes and subterfuge, photons from far-off light sources, such as blazars, could go up against a continuous exchange of identity in their journey through the Universe. This is an operation that would allow these very tiny particles of light to escape an enemy which, if encountered, would annihilate them. This is the phenomenon studied by a group of researchers from the University of Salento, Bari, the National Institute for Nuclear Physics (INFN), the National Institute for Astrophysics (INAF) and SISSA thanks to brand new simulation models that reproduce the complexity of the cosmos as never before. Normally, very high energy photons (gamma rays) should "collide" with the background light emitted by galaxies transformed into pairs of matter and antimatter particles, as envisaged by the Theory of Relativity. For this reason, the sources of very high energy gamma rays should appear significantly less bright than what is observed in many cases.

A possible explanation for this surprising anomaly is that light photons are transformed into hypothetical weakly-interacting particles, "axions" which, in turn, would change into photons, all due to the interaction with magnetic fields. With these metamorphoses, a part of the photons would escape interaction with the intergalactic background light that would make them disappear. The importance of this process is emphasised by the study published on Physical Review Letters, which re-created an extremely refined model of the Cosmic Web, a network of filaments composed of gas and dark matter present throughout the Universe and of its magnetic fields. The aforementioned effects are now awaiting comparison with those obtained experimentally through Cherenkov Telescope Array new generation telescopes.

In this research, through complex and unprecedented computer simulations made at the CSCS Supercomputing Centre in Lugano, scholars have reproduced the so-called Cosmic Web and the magnetic fields associated with this to investigate the possibility, advanced from previous theories, that photons from a light source are transformed into axions, hypothetical elementary particles, on interacting with an extragalactic magnetic field. Axions could then be retransformed into photons by interacting with other magnetic fields. Researchers Daniele Montanino, Franco Vazza, Alessandro Mirizzi and Matteo Viel explain: "Photons from luminous bodies disappear when they encounter extragalactic background light (EBL). But if on their journey they head into these transformations as envisaged by these theories, it would explain why, in addition to giving very important information on processes that occur in the universe, distant celestial bodies are brighter than expected from an observation on Earth. These changes would, in fact, enable a greater number of photons to reach the Earth".

In the simulations made by scientists, thanks to the wealth of magnetic fields present in the Cosmic Web's filaments recreated with the simulations, the conversion phenomenon would seem much more relevant than predicted by previous models: "Our simulations reproduce a very realistic picture of the cosmos' structure. From what we have observed, the distribution of the Cosmic Web envisaged by us would markedly increase the probability of these transformations". The next step in the research? To compare simulation results with the experimental data obtained through the use of the Cherenkov Telescope Array Observatories detectors, the new-generation astronomical observatories, one of which is positioned in the Canary Islands and the other in Chile, that will study the Universe through very high energy gamma rays.
-end-


Scuola Internazionale Superiore di Studi Avanzati

Related Magnetic Fields Articles from Brightsurf:

Physicists circumvent centuries-old theory to cancel magnetic fields
A team of scientists including two physicists at the University of Sussex has found a way to circumvent a 178-year old theory which means they can effectively cancel magnetic fields at a distance.

Magnetic fields on the moon are the remnant of an ancient core dynamo
An international simulation study by scientists from the US, Australia, and Germany, shows that alternative explanatory models such as asteroid impacts do not generate sufficiently large magnetic fields.

Modelling extreme magnetic fields and temperature variation on distant stars
New research is helping to explain one of the big questions that has perplexed astrophysicists for the past 30 years - what causes the changing brightness of distant stars called magnetars.

Could megatesla magnetic fields be realized on Earth?
A team of researchers led by Osaka University discovered a novel mechanism called a ''microtube implosion,'' demonstrating the generation of megatesla-order magnetic fields, which is three orders of magnitude higher than those ever experimentally achieved.

Superconductors are super resilient to magnetic fields
A Professor at the University of Tsukuba provides a new theoretical mechanism that explains the ability of superconductive materials to bounce back from being exposed to a magnetic field.

A tiny instrument to measure the faintest magnetic fields
Physicists at the University of Basel have developed a minuscule instrument able to detect extremely faint magnetic fields.

Graphene sensors find subtleties in magnetic fields
Cornell researchers used an ultrathin graphene ''sandwich'' to create a tiny magnetic field sensor that can operate over a greater temperature range than previous sensors, while also detecting miniscule changes in magnetic fields that might otherwise get lost within a larger magnetic background.

Twisting magnetic fields for extreme plasma compression
A new spin on the magnetic compression of plasmas could improve materials science, nuclear fusion research, X-ray generation and laboratory astrophysics, research led by the University of Michigan suggests.

How magnetic fields and 3D printers will create the pills of tomorrow
Doctors could soon be administering an entire course of treatment for life-threatening conditions with a 3D printed capsule controlled by magnetic fields thanks to advances made by University of Sussex researchers.

Researchers develop ultra-sensitive device for detecting magnetic fields
The new magnetic sensor is inexpensive to make, works on minimal power and is 20 times more sensitive than many traditional sensors.

Read More: Magnetic Fields News and Magnetic Fields Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.