"Well Folks,how will this fit? "NASA astronomers detect high-energy 'signal' from outside our galaxy in 'serendipitous discovery'
Posted Fri 12 Jan 2024 at 9:47pmFriday 12 Jan 2024 at 9:47pm, updated 21h ago21 hours ago
This artist's concept shows the entire sky in gamma rays, with magenta
circles illustrating the direction from which more high-energy gamma
rays seem to be arriving.(Supplied: NASA's Goddard Space Flight Center)Link copied
Astronomers
have discovered a surprising light "signal" from outside of our galaxy
after analysing 13 years of data from NASA's Fermi Gamma-ray Space
Telescope.
Key points:
- The source of a high-energy burst of light found outside our galaxy is unknown
- NASA astronomers detected it after analysing data from a powerful gamma ray telescope
- They were originally searching for a feature that could help us understand the "early universe"
The
powerful telescope detects gamma rays, which are extremely high-energy
bursts of light created by violent events like exploding stars and
nuclear blasts.
Alexander
Kashlinsky β a cosmologist at the University of Maryland and NASA's
Goddard Space Flight Center in Greenbelt β presented an unexpected
finding from the observatory at this week's meeting of the American
Astronomical Society.
"It is a completely serendipitous discovery," he said at the event in New Orleans.
"We found a much stronger signal, and in a different part of the sky, than the one we were looking for."
The
gamma-ray signal was intriguingly found in a similar direction as
another unexplained feature produced by some of the most energetic
cosmic particles ever detected.
A research paper describing the discovery was published in The Astrophysical Journal Letters on Wednesday.
A quest to understand the 'early universe'
The
research team was originally searching for a gamma-ray feature related
to the cosmic microwave background (CMB), which is the oldest known
light in the universe.
Scientists
say the CMB is a relic from when the hot, expanding universe had cooled
enough to form the first atoms after the Big Bang.
The
subsequent burst of light was stretched by the expansion of the
universe over 13 billion years and was first detected in the form of
faint microwaves in 1965.
NASAβs Fermi Gamma-ray Space Telescope, illustrated here, scans the entire sky every three hours as it orbits Earth.(Supplied: NASA's Goddard Space Flight Center)
Astronomers
in the 1970s discovered the CMB had a "dipole" structure, meaning it
has two ends with temperature deviations in opposite directions.
The
CMB was found to be sightly hotter with more microwaves than average
toward the constellation Leo, and colder by the same amount with fewer
microwaves than average in the opposite direction.
Scientists generally regard this dipole pattern as a result of the movement of our solar system relative to the CMB.
But
the research team hoped to confirm or challenge that idea by studying
other forms of light, such as gamma rays, for a similar pattern.
Co-author
Fernando Atrio-Barandela, a professor of theoretical physics at the
University of Salamanca in Spain, said such a measurement is important.
"A
disagreement with the size and direction of the CMB dipole could
provide us with a glimpse into physical processes operating in the very
early universe, potentially back to when it was less than a trillionth
of a second old," he said.
The team combined 13 years of gamma ray data from NASA's Fermi Large Area Telescope to analyse the cosmic gamma ray background.
Co-author
Chris Shrader β who is an astrophysicist at the Catholic University of
America in Washington and Goddard β said the researchers found a gamma
ray dipole, but its peak was located in the southern sky, far from the
CMB's.
"Its magnitude is 10 times greater than what we would expect from our motion," he said.
"While
it is not what we were looking for, we suspect it may be related to a
similar feature reported for the highest-energy cosmic rays."
This similar feature was first observed by the Pierre Auger Observatory in Argentina in 2017.
The
observatory discovered a dipole peak of ultra high-energy cosmic rays
in a similar location and magnitude to the gamma ray peak.
The
researchers suspect the two phenomena are linked and that there is an
unidentified source producing both the gamma rays and the ultra
high-energy particles.
To
solve this cosmic conundrum, astronomers must either locate these
mysterious sources or propose alternative explanations for both
features.
I found it interesting. Can only wonder what believers will make of it
jtg