Los Alamos National Laboratory

Los Alamos National Laboratory

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Resource Revolutions

Why are there so many anti-electrons in our region of the galaxy?
January 1, 2020
Resource Revolution

A pair of nearby pulsars—ultradense, highly magnetized, and rapidly rotating neutron stars, shown here within a high-energy gamma-ray sky map—seemed a likely source for the excess of positrons flying through space and raining down on the earth. Recent observations, however, suggest otherwise. CREDIT: HAWC collaboration

If pulsars are not the source, then what is?

What is producing the excess positrons zipping through our part of the galaxy? Whatever it is must be within about a thousand light years of Earth, about 1 percent of the diameter of the galaxy; otherwise, the positrons would have lost too much energy from interactions with interstellar radiation and magnetic fields to account for their measured abundance and energy. Theorists have posited only a handful of possible sources. Perhaps the most likely would be a collection of astrophysical objects that produce and accelerate positrons. This would include pulsars, supernovae, and micro-quasars, and the most likely of these, researchers expected, would be pulsars. But it’s just not a match with the latest observational data.


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