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The Tiny Dots in This Image Aren't Stars or Galaxies. They're Black Holes
https://www.sciencealert.com ^ | 2 JANUARY 2022 | MICHELLE STARR

Posted on 01/03/2022 5:56:49 AM PST by Red Badger

(LOFAR/LOL Survey)

The image above may look like a fairly normal picture of the night sky, but what you're looking at is a lot more special than just glittering stars. Each of those white dots is an active supermassive black hole.

And each of those black holes is devouring material at the heart of a galaxy millions of light-years away – that's how they could be pinpointed at all.

Totaling 25,000 such dots, astronomers created the most detailed map to date of black holes at low radio frequencies in early 2021, an achievement that took years and a Europe-sized radio telescope to compile.

"This is the result of many years of work on incredibly difficult data," explained astronomer Francesco de Gasperin of the University of Hamburg in Germany. "We had to invent new methods to convert the radio signals into images of the sky."

(LOFAR/LOL Survey)

When they're just hanging out not doing much, black holes don't give off any detectable radiation, making them much harder to find. When a black hole is actively accreting material – spooling it in from a disc of dust and gas that circles it much as water circles a drain – the intense forces involved generate radiation across multiple wavelengths that we can detect across the vastness of space.

What makes the above image so special is that it covers the ultra-low radio wavelengths, as detected by the LOw Frequency ARray (LOFAR) in Europe. This interferometric network consists of around 20,000 radio antennas, distributed throughout 52 locations across Europe.

Currently, LOFAR is the only radio telescope network capable of deep, high-resolution imaging at frequencies below 100 megahertz, offering a view of the sky like no other. This data release, covering four percent of the Northern sky, was the first for the network's ambitious plan to image the entire Northern sky in ultra-low-frequencies, the LOFAR LBA Sky Survey (LoLSS).

Because it's based on Earth, LOFAR does have a significant hurdle to overcome that doesn't afflict space-based telescopes: the ionosphere. This is particularly problematic for ultra-low-frequency radio waves, which can be reflected back into space. At frequencies below 5 megahertz, the ionosphere is opaque for this reason.

The frequencies that do penetrate the ionosphere can vary according to atmospheric conditions. To overcome this problem, the team used supercomputers running algorithms to correct for ionospheric interference every four seconds. Over the 256 hours that LOFAR stared at the sky, that's a lot of corrections.

This is what has given us such a clear view of the ultra-low-frequency sky.

"After many years of software development, it is so wonderful to see that this has now really worked out," said astronomer Huub Röttgering of Leiden Observatory in the Netherlands.

Having to correct for the ionosphere has another benefit, too: It will allow astronomers to use LoLSS data to study the ionosphere itself. Ionospheric traveling waves, scintillations, and the relationship of the ionosphere with solar cycles could be characterized in much greater detail with the LoLSS. This will allow scientists to better constrain ionospheric models.

And the survey will provide new data on all sorts of astronomical objects and phenomena, as well as possibly undiscovered or unexplored objects in the region below 50 megahertz.

"The final release of the survey will facilitate advances across a range of astronomical research areas," the researchers wrote in their paper.

"[This] will allow for the study of more than 1 million low-frequency radio spectra, providing unique insights on physical models for galaxies, active nuclei, galaxy clusters, and other fields of research. This experiment represents a unique attempt to explore the ultra-low frequency sky at a high angular resolution and depth."

The results have been published in Astronomy & Astrophysics.

A version of this article was first published in February 2021.


TOPICS: Arts/Photography; Astronomy; History; Science
KEYWORDS: astronomy; blackholes; physics; science; stringtheory
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To: Track9

This thread needs a picture of the Time Bandits.

Hell Yea!


61 posted on 01/03/2022 6:22:33 PM PST by Jet Jaguar
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To: DannyTN

There it is.


62 posted on 01/03/2022 6:23:05 PM PST by Jet Jaguar
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To: Red Badger

I can’t even fathom this.


63 posted on 01/04/2022 1:14:36 AM PST by Bullish (This is the most bloated and most inept govt in history.)
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To: DoodleBob

bttt


64 posted on 01/04/2022 1:48:28 AM PST by linMcHlp
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To: Bullish

https://www.youtube.com/watch?v=9nZc5SnIAp0


65 posted on 01/04/2022 5:16:40 AM PST by Red Badger (Homeless veterans camp in the streets while illegal aliens are put up in hotels.....................)
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To: Red Badger

That’s racist, or something.


66 posted on 01/04/2022 5:18:55 AM PST by dfwgator (Endut! Hoch Hech!)
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To: dfwgator

Inside the center every galaxy is a Black Hole.

Eventually the Black Holes will all start accreting each other and then comes the Big Crunch..................


67 posted on 01/04/2022 5:28:39 AM PST by Red Badger (Homeless veterans camp in the streets while illegal aliens are put up in hotels.....................)
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To: Red Badger

By definition, the white dots are NOT black holes. No light escapes from a black hole.


68 posted on 01/04/2022 6:37:53 AM PST by BubbaBasher ("Liberty will not long survive the total extinction of morals" - Sam Adams)
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To: BubbaBasher

That’s not light from the Black Hole itself, but energy of low frequencies caused by the matter being accreted in the planar disc that surrounds the Black Hole’s Event Horizon.............


69 posted on 01/04/2022 6:44:35 AM PST by Red Badger (Homeless veterans camp in the streets while illegal aliens are put up in hotels.....................)
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To: Red Badger

Nevermind.


70 posted on 01/04/2022 7:11:30 AM PST by BubbaBasher ("Liberty will not long survive the total extinction of morals" - Sam Adams)
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To: SunkenCiv

Just spent an hour shoveling after a 13-inch snowfall...
Guess those are black hoIes I can see dancing before my eyes now...
Sometimes 88 can be a bitch...


71 posted on 01/04/2022 10:44:32 AM PST by SuperLuminal (Where is another Sam Adams now that we desperately need him?)
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To: SuperLuminal

88 looks like four black holes...


72 posted on 01/04/2022 2:06:35 PM PST by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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