(ORDO NEWS) — Most of the light passing through the universe is invisible to the human eye. Beyond the medium wavelengths that we can see, there is a whole cosmos shining in high and low energy radiation.
But we humans are smart little animals, and we’ve managed to create tools that can see light that we can’t.
One of them is NASA‘s Fermi Gamma-ray Space Telescope, an observatory in low Earth orbit that monitors the sky for gamma rays, the most energetic light in the universe.
Fermi constantly monitors the entire sky, observing gamma ray sources and how they change over time, providing astronomers with a map of the different gamma ray sources that we can detect.
This data is compiled into a catalog that scientists can use to investigate the production of gamma rays.
The animation represents a year of fluctuations in gamma radiation from 1525 sources, represented by pulsating purple circles, collected between February 2022 and February 2023, each frame representing three days of observations.
The larger the circle, the brighter the gamma radiation. The yellow circle, meanwhile, represents the Sun’s apparent path across the sky at that time period.
“We were inspired to assemble this database by astronomers who study galaxies and want to compare visible and gamma-ray light curves over long time scales,” says astrophysicist of NASA’s Marshall Space Flight Center in Huntsville.
“We have been receiving requests to process one object at a time. Now the scientific community has access to all analyzed data throughout the catalog.”
Most of the flashing lights you see come from galaxies known as blazars. This is a subset of quasar galaxies.
A quasar is a galaxy with an extremely active nucleus, which means that the supermassive black hole is consuming matter at a tremendous rate.
This material is heated up by the extreme activity around the black hole, so that it scatters all over space. Quasars emit the brightest light in the universe.
Some of these quasars have plasma jets emitted from the core of the galaxy. As the black hole feeds, some of the material orbiting it is deflected and accelerated along magnetic field lines outside the event horizon.
Upon reaching the poles, this material is ejected into space at high speeds, often approaching the speed of light in a vacuum.
A blazar is a quasar whose jet is directed at or near Earth. Because of this orientation, the light appears even brighter across the entire spectrum.
Blazars are known sources of gamma rays, but their light fluctuates in fairly short periods of time; their fluctuations could help astronomers study how these giants feed.
Combined with other data, they can also help answer questions about the universe.
For example, only recently the detection of neutrinos by observatories such as IceCube in Antarctica has been traced back to blazar galaxies.
Blazars represent more than 90 percent of the gamma ray sources in the new addition to the Fermi gamma ray. -beam directory.
Other gamma-emitting objects include neutron stars called pulsars, broken remnants of material left over from supernova explosions, and binary systems such as binary neutron stars.
And there is gamma radiation from the plane of the Milky Way galaxy, represented in the animation as a mottled orange band running through the center of the image.
There, a brighter color corresponds to a brighter glow.
We hope that long-term observations will provide a deeper understanding of some of the phenomena associated with gamma-ray sources.
For example, tracing neutrinos to a brighter period of blazar activity could help narrow down the processes that produce these mysterious particles.
“Having a historical database of light curves,” says astrophysicist Michela Negro of the University of Maryland, Baltimore County and NASA’s Goddard Space Flight Center, “could provide new insights into past events with the help of a multi-messenger.”
And we get a hint of how we could see the universe if we had alien eyes.
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