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3838 - FAST
RADIO BURSTS - what
can radio waves teach us? For over a
decade now, so-called fast radio bursts (FRBs) have been puzzling scientists.
These ultra-short-lived, bright flashes of radio waves across the sky happen
all day, but no one yet knows what causes them.
------ 3838 - FAST RADIO BURSTS - what can radio waves teach us?
- Radio waves are the low frequency, broad
wavelength end of the electromagnetic spectrum.
It is light that our eyes can not see.
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- Although FRBs are still a mystery, new
observations of this strange phenomenon may actually help astronomers learn
more about our own galactic neighborhood.
Astronomers are measuring our Milky Way's mass using an FRB, and, it
turns out our galaxy is lighter than expected.
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- Astronomers built an observatory called
the Deep Synoptic Array (DSA), a collection of 110 radio antennas nestled in
the Owens Valley of Central California on the ancestral lands of the Big Pine
Paiute Tribe, to make more precise measurements of FRBs.
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- Their goal is to pinpoint the location on
the sky of each FRB they observe, to help figure out where these flashes
originate. This task requires highly detailed resolution, the equivalent of
spotting a dime on the surface of the moon.
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- At the same time, the array must survey a
large chunk of the sky to have any hope of spotting the extremely short bursts.
Surveying a large amount of sky means processing a lot of data, so the array's
computers are processing 24 gigabytes per second. This is far beyond the
capabilities of most computers.
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- In the long run, astronomers hope to build
an even more advanced FRB observatory, nicknamed “DSA-2000”, an array of two
thousand radio dishes in the Nevada desert.
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- DSA-110 has helped astronomers discover 30
FRBs with precise locations, more than matching the 21 scientists had
previously traced in the years since the first FRB was detected in 2007.
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- As it turns out, more than 80% of baryonic
matter, not dark matter, but actually matter, is invisible in the nearby
universe. This hidden matter is really
spread out, making it hard for our telescopes to see. Dark matter is the mysterious substance that
astronomers can't see directly, but have observed through its gravitational
signature on galaxies.
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- As the radio waves travel from distant
galaxies to our antennas on Earth, certain frequencies of the waves will be
delayed, an indicator of how much stuff there is between the observer and the
FRB. Data from the DSA revealed that our Milky Way has far less regular matter
than astronomers expected.
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- Whereas most of the universe is made of
around 16% regular matter and 84% dark matter, our Milky Way is less than 10%
regular matter and over 90% dark matter.
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- These unexpected results strongly support
scenarios predicted by galaxy-formation simulations where feedback processes
expel matter from the halos of galaxies.
These processes are fundamental to galaxy formation, whereby matter is
funneled in and blown out of galaxies in cycles.
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- This is only the first year of observations
with the newly-christened DSA, which began commissioning in February 2022, and
the observatory is still ramping up, with only 63 of the 110 dishes involved in
the new research. So there's likely much more to come out of that California
valley to help unravel the story of FRBs and more.
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- Fast radio bursts (FRBs) are
ultra-short-lived, bright flashes of radio waves that happen across the sky happen
all day, but no one yet knows what causes them.
-
- A gaslaxy's unexpected lightness could hint
at blowouts in our galaxy's past. These results strongly support scenarios
predicted by galaxy-formation simulations where feedback processes expel matter
from the halos of galaxies. These processes are fundamental to galaxy
formation, whereby matter is funneled in and blown out of galaxies in cycles.
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January 22, 2022 FAST
RADIO BURSTS - radio waves teach us? 3838
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--------------------- --- Monday, January 23, 2023 ---------------------------
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