NASA Explains Fermi Telescope Does Not Detect Gamma-Rays From Nearby Supernova

Space.com

NASA’s Fermi Gamma-ray Space Telescope "detected none of the high-energy gamma-ray light" from a nearby supernova. NASA explains.   Credit: NASA Goddard Space Flight Center

Transcript

00:00NASA's Fermi Gamma-ray Space Telescope

00:04watches the sky for gamma rays, the highest energy form of light.

00:08These detections help scientists learn more about the most powerful

00:12events in the cosmos. However, a recent absence

00:16of gamma ray detection may have been just as informative.

00:20Cosmic rays are small particles like protons and helium nuclei

00:24traveling at nearly the speed of light. It takes a lot of energy to

00:28accelerate them to that speed, so scientists assume they're driven by

00:32powerful events like exploding stars, called supernovae.

00:36Because cosmic rays are charged particles, they interact with magnetic

00:40fields as they travel. These interactions mean they don't follow a

00:44straight line from their sources, and so scientists can't trace where they came from.

00:48But when cosmic rays smash into other particles, they produce gamma rays.

00:52And gamma rays do travel to us straight from their

00:56sources. Fermi has even detected such gamma rays from

01:00supernova remnants, which are thousands of years old.

01:04If supernovae and their remnants really are a key source of cosmic rays,

01:08then calculations tell astronomers how many gamma rays Fermi should detect.

01:12But so far, the telescope hasn't seen enough gamma

01:16rays from these sources. Scientists had suspected

01:20this was because the supernovae were too far away, or observations began

01:24too late, well after peak production.

01:28In May 2023, Fermi observed the most luminous nearby

01:32supernova seen since the mission launched 15 years ago.

01:36It captured data from the first few weeks of the explosion, when scientists

01:40anticipated the greatest production of cosmic rays. But Fermi

01:44didn't see any gamma rays from the explosion.

01:48Scientists aren't yet sure what this means for the link between cosmic rays and supernovae.

01:52There's still a lot of work left to do, but Fermi's non-detection

01:56has added a very important new piece to this high-energy

02:00puzzle.

Category

Transcript

Recommended