Are pulsars the key to finding dark matter?

Ah, dark matter particles, what may you be? The reply nonetheless eludes us, and astronomers preserve attempting new concepts to search out them. A brand new paper in Bodily Overview Letters means that if dark matter is fabricated from axions, we would see their remnant glow close to pulsars.

Whereas the preferred candidate particles for dark matter are weakly interacting huge particles (WIMPs), one other fashionable possibility is the hypothetical axion. Axions weren’t initially proposed to unravel dark matter, however slightly to deal with some vexing subtleties in particle physics. [Fun fact: Axion is a brand of dishwashing liquid popular in Latin America. Axions are so named because they “clean up” the particle physics problem.]

In accordance with concept, axions are low-mass, chargeless particles that would not work together strongly with common matter or mild, which appears like an ideal dark matter candidate. Axions can decay into photons, however the mild produced can be so diffuse and faint that we will not detect it.

This new examine proposes a means we would be capable to detect the remnant glow of axions. In the event that they exist, axions may very well be produced in extraordinarily robust magnetic fields, akin to these round neutron stars and black holes. The strongest electromagnetic fields are round pulsars, so that will be the most effective place to look. Pulsars are neutron stars that generate highly effective streams of power from their magnetic poles. The polar regions would additionally produce huge portions of axions, a few of which might decay into mild. So in concept pulsar mild ought to comprise the sunshine of axion decay.

So the authors used a primary mannequin to estimate the quantity of sunshine that will be produced by axion decay and what the spectrum of that mild can be. They then simulated how this extra would seem within the radio flashes of highly effective pulsars. They then in contrast their mannequin to observations of 27 close by pulsars to see if they may detect an extra of radio mild that will show axion decay.

Sadly, the crew discovered no proof for axions. Based mostly on their observations, they have been capable of constrain the mass of axions in the event that they do exist. Based mostly on the information, axions will be no lighter than 10^-8 electron volts and no heavier than 10^-5 electron volts, which is way lighter than even neutrinos.

One of many strengths of this result’s that it would not assume axions are dark matter, solely that axions exist. That is actually extra of a particle physics check than a cosmological one, which is why the mass constraint will be so direct. However as soon as once more the particles of dark matter stay hidden. Assuming dark matter particles exist, which is a narrative for an additional time.