2023-10-06 18:00:13
The Crab Nebula is a remnant of a supernova explosion that contains a pulsar at its center. – NASA/CXC/ASU/J. HESTER ET AL.
MADRID, 6 Oct. (EUROPA PRESS) –
A group of astrophysicists has shown that if dark matter is composed of axions, it can manifest itself in the form of an additional subtle glow from pulsating stars.
The light emitted by axions – a subatomic particle whose existence has not yet been proven – detectable in the form of radio waves, It would be only a small fraction of the total light that these brilliant cosmic beacons send our way.
It is necessary to know very precisely what a pulsar would be like without axions and what a pulsar would be like with axions to be able to see the difference, let alone quantify that difference and convert it into a measure of an amount of dark matter.
This is exactly what a team of physicists and astronomers has done. In a collaborative effort between scientists at the universities of Princeton and Amsterdam, a comprehensive theoretical framework has been built that allows a detailed understanding of how axions are produced, how axions escape the gravitational pull of the neutron star, and how, during his escape, They are converted into low energy radio radiation.
The theoretical results were then transferred to a computer to model axion production around pulsars, using state-of-the-art plasma numerical simulations that were originally developed to understand the physics behind how pulsars emit radio waves, reports the University of Amsterdam.
Once virtually produced, the propagation of the axions through the electromagnetic fields of the neutron star was simulated. This allowed the researchers to quantitatively understand the subsequent production of radio waves and model how this process it would provide an additional radio signal in addition to the intrinsic emission generated by the pulsar itself.
The theory and simulation results were then subjected to a first observational test. Using observations of 27 nearby pulsars, the researchers compared the observed radio waves with the models, to see if any measured excesses could provide evidence for the existence of axions. Unfortunately, the answer was “no,” or perhaps more optimistically, “not yet.” Axions don’t immediately jump out at us, but perhaps that wasn’t expected. If dark matter revealed its secrets so easily, it would have been observed long ago.
Therefore, hope for definitive detection of axions now lies in future observations. Meanwhile, the current non-observation of radio signals from axions is an interesting result in itself. The first comparison between simulations and real pulsars has put the strictest limits yet on the interaction that axions can have with light, according to the authors, whose work is published in Physical Review Letters.
The ultimate goal is to prove that axions exist or to make sure that it is extremely unlikely that axions are a constituent of dark matter. The new results are only a first step in that direction; They are just the beginning of what could become a completely new and highly interdisciplinary field that has the potential to dramatically advance the search for axions, the authors say.
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