Artist’s representation of a magnetar. Credit: ESO/L. Calçada
A University of Colorado at Boulder astrophysicist is browsing the light originating from a remote, and very effective celestial things, for what might be the most evasive compound in deep space: dark matter.
In 2 current research studies, Jeremy Darling, a teacher in the Department of Astrophysical and Planetary Sciences, has actually taken a deep take a look at PSR J1745-2900. This body is a magnetar, or a kind of collapsed star that creates an exceptionally strong electromagnetic field.
“It’s the best natural dark matter detector we know about,” stated Darling, likewise of the Center for Astrophysics and Space Astronomy (CASA) at CU Boulder.
He described that dark matter is a sort of cosmic glue—an as-of-yet unknown particle that comprises approximately 27% of the mass of deep space and assists to bind together galaxies like our own Milky Way. To date, researchers have actually mainly led the hunt for this unnoticeable matter utilizing lab devices.
Darling has actually taken a various method in his newest research study: Drawing on telescope information, he’s peering at PSR J1745-2900 to see if he can spot the faint signals of one prospect for dark matter—a particle called the axion—changing into light. So far, the researcher’s search has actually turned up empty. But his outcomes might assist physicists operating in laboratories around the globe to limit their own looks for the axion.
The brand-new research studies are likewise a suggestion that scientists can still seek to the skies to resolve a few of the hardest concerns in science, Darling stated. He released his preliminary of outcomes this month in The Astrophysical Journal Letters and Physical Review Letters.
“In astrophysics, we find all of these interesting problems like dark matter and dark energy, then we step back and let physicists solve them,” he stated. “It’s a shame.”
Natural experiment
Darling wishes to alter that—in this case, with a little assistance from PSR J1745-2900.
This magnetar orbits the supermassive great void at the center of the Milky Way Galaxy from a range of less than a light-year away. And it’s a force of nature: PSR J1745-2900 creates an electromagnetic field that is approximately a billion times more effective than the most effective magnet on Earth.
An picture of the middle of the Milky Way Galaxy revealing the area of the supermassive great void at its center, called Sagittarius A*, and the neighboring magnetar PSR J1745-2900. Credit: NASA/CXC/FIT/E
“Magnetars have all of the magnetic field that a star has, but it’s been crunched down into an area about 20 kilometers across,” Darling stated.
And it’s where Darling has actually fished for dark matter.
He described that researchers have yet to find a single axion, a theoretical particle very first proposed in the 1970s. Physicists, nevertheless, forecast that these ephemeral little bits of matter might have been developed in huge numbers throughout the early life of deep space—and in big sufficient amounts to discuss the universes’ additional mass from dark matter. According to theory, axions are billions or perhaps trillions of times lighter than electrons and would connect just hardly ever with their environments.
That makes them practically difficult to observe, with one huge exception: If an axion goes through a strong electromagnetic field, it can change into light that scientists could, in theory, spot.
Scientists, consisting of a group at JILA on the CU Boulder school, have actually utilized lab-generated electromagnetic fields to attempt to record that shift in action. Darling and other researchers had a various concept: Why not attempt the very same search however on a much larger scale?
“Magnetars are the most magnetic objects we know of in the universe,” he stated. “There’s no way we could get close to that strength in the lab.”
Narrowing in
To utilize that natural electromagnetic field, Darling made use of observations of PSR J1745-2900 taken by the Karl G. Jansky Very Large Array, an observatory in New Mexico. If the magnetar was, certainly, changing axions into light, that transformation may appear in the radiation emerging from the collapsed star.
The effort is a bit like trying to find a single needle in a truly, truly huge haystack. Darling stated that while theorists have actually put limitations on how heavy axions may be, these particles might still have a vast array of possible masses. Each of those masses, in turn, would produce light with a particular wavelength, practically like a finger print left by dark matter.
Several of the 28 meal antennae that comprise the Very Large Array, situated in Socorro, New Mexico, U.S.A.. Credit: CGP Grey, CC BY 2.0
Darling hasn’t yet found any of those unique wavelengths in the light originating from the magnetar. But he has actually had the ability to utilize the observations to penetrate the possible presence of axions throughout the best series of masses yet—okay for his very first effort. He included that such studies can match the work occurring in Earth-based experiments.
Konrad Lehnert concurred. He’s part of an experiment led by Yale University—called, not remarkably, HAYSTAC—that is looking for axions utilizing electromagnetic fields developed in laboratories throughout the nation.
Lehnert described that astrophysical research studies like Darling’s might serve as a sort of scout in the hunt for axions—determining intriguing signals in the light of magnetars, which lab scientists might then go into with much higher accuracy.
“These well-controlled experiments would be able to sort out which of the astrophysical signals might have a dark matter origin,” stated Lehnert, a fellow at JILA, a joint research study institute in between CU Boulder and the National Institute of Standards and Technology (NIST).
Darling prepares to continue his own search, which suggests looking even better at the magnetar at the center of our galaxy: “We need to fill in those gaps and go even deeper.”
References:
“New Limits on Axionic Dark Matter from the Magnetar PSR J1745-2900” by Jeremy Darling, 7 September 2020, The Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/abb23f
“Search for Axionic Dark Matter Using the Magnetar PSR J1745-2900” by Jeremy Darling, 17 September 2020, Physical Review Letters.
DOI: 10.1103/PhysRevLett.125.121103
