October 2, 2023

Strange Galactic Signal Coming From the Center of the Galaxy Has Potential New Explanation

View of the gamma-ray sky. Credit: NASA/DOE/Fermi LAT Collaboration
Scientists from The Australian National University (ANU) have found an alternative explanation for a strange gamma-ray signal originating from the center of the galaxy, which was long claimed as a signature of dark matter.
Gamma-rays are the kind of electromagnetic radiation with the fastest wavelength and greatest energy.
Co-author of the research study Associate Professor Roland Crocker stated this particular gamma-ray signal– referred to as the Galactic Center Excess– may actually come from a particular type of rapidly-rotating neutron star, the super-dense stellar residues of some stars a lot more huge than our sun.

The Galactic Center Excess is an unforeseen concentration of gamma-rays emerging from the center of our galaxy that has long puzzled astronomers.
” Our work does not toss any doubt on the existence of the signal, but uses another possible source,” Associate Professor Crocker stated.
” It is based upon millisecond pulsars– neutron stars that spin actually quickly– around 100 times a 2nd.
” Scientists have previously spotted gamma-ray emissions from individual millisecond pulsars in the area of the solar system, so we understand these objects give off gamma-rays. Our model demonstrates that the integrated emission from a whole population of such stars, around 100,000 in number, would produce a signal entirely compatible with the Galactic Center Excess.”.
The discovery may indicate scientists need to re-think where they try to find hints about dark matter.
” The nature of dark matter is entirely unknown, so any prospective clues amass a lot of enjoyment,” Associate Professor Crocker stated.
” But our outcomes indicate another important source of gamma-ray production.
” For circumstances, the gamma-ray signal from Andromeda, the next closest large galaxy to our own may be mostly due to millisecond pulsars.”.
ANU Masters trainee Anuj Gautam led the research study, which also included researchers from The Australian Defence Force Academy, University of Canterbury, and University of Tokyo..
The research study has actually been published in the journal Nature Astronomy.
Reference: “Millisecond pulsars from accretion-induced collapse as the origin of the Galactic Centre gamma-ray excess signal” by Anuj Gautam, Roland M. Crocker, Lilia Ferrario, Ashley J. Ruiter, Harrison Ploeg, Chris Gordon and Oscar Macias, 28 April 2022, Nature Astronomy.DOI: 10.1038/ s41550-022-01658-3.