Alcyoneus : The discovery of a radio galaxy of at least 5 Mpc

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https://arxiv.org/abs/2202.05427

3 billion light-years from Earth, roughly 16.3 million light-years long, roughly 153.77 times longer than the Milky Way.

My question is : is it still there or has the black hole swallowed it by now.

We discover what is in projection the largest known structure of galactic origin: a giant radio galaxy with a projected proper length of . The source, named Alcyoneus, was first identified in low-resolution LOFAR Two-metre Sky Survey images from which angularly compact sources had been removed. Being an extreme example in its class, Alcyoneus could shed light on the main mechanisms that drive radio galaxy growth. We find that – beyond geometry – Alcyoneus and its host galaxy appear suspiciously ordinary: the total low-frequency luminosity density, stellar mass and supermassive black hole mass are all lower than, though similar to, those of the medial giant radio galaxy (percentiles , and , respectively). The source resides in a filament of the Cosmic Web, with which it might have significant thermodynamic interaction. At , the pressures in the lobes are the lowest hitherto found, and Alcyoneus therefore represents one of the most promising radio galaxies yet to probe the warm-hot intergalactic medium…

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More detail with pictures here:

https://earthsky.org/space/largest-galaxy-yet-seen-in-radio-alcyoneus/

Excerpts (emphasis mine):

” Astronomers said last week (February 16, 2022) they’ve found the largest galaxy yet seen, not in visible light, but via radio astronomy. ”

” Scientists have named the new galaxy Alcyoneus, for the giant of Greek myth. They said it’s so large that it might provide insights about the the cosmic web – the observed network of filaments and clusters, made of galaxies, plus the great voids between them – that astronomers observe all around us in the modern universe. ”

” Alcyoneus lies relatively nearby as galaxies go, only 3 billion light-years away. It spans an area in our sky the size of the full moon.” (But cannot be seen with our eyes, as it mostly shines at radio frequencies.)

” Alcyoneus gets its enormous size from two huge jets [of dust shooting away at close to the speed of light] emanating from the galaxy’s central supermassive black hole. ”

” Bottom line: Astronomers have discovered the largest radio galaxy yet. It would take 100 Milky Way galaxies laid end to end to equal Alcyoneus and its jets. The jets are so tenuous that astronomers can see subtle changes in them as they move through the intergalactic medium. Astronomers hope this subtle movement will help them understand the voids in the cosmic web. ”

Also from the University of Leiden, in The Netherlands, where the discovery was made by a doctoral student “by a stroke of luck”:

https://www.universiteitleiden.nl/en/news/2022/02/astronomers-find-largest-radio-galaxy-ever

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Alex5723

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And the answer to my question ? is it still there ?

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Please Alex, why don’t you ask me again three thousand million years from now? About your question, I don’t expect to hear definite news from there enough to answer it authoritatively much before then. Of course one never knows and something might transpire earlier than that. If it does, I might remember to tell you. Right now it seems like the black hole there is big, but not particularly big for even a more modest size galaxy. But it is blowing stuff with its two jets like there is no tomorrow.

There is more about the jets and the rest of it in the discovery paper’s preview in ArXiv, but the PDF is near 34 MB, so I cannot attach a copy here. Sorry.

Ex-Windows user (Win. 98, XP, 7); since mid-2017 using also macOS. Presently on Monterey 12.15 & sometimes running also Linux (Mint).

MacBook Pro circa mid-2015, 15" display, with 16GB 1600 GHz DDR3 RAM, 1 TB SSD, a Haswell architecture Intel CPU with 4 Cores and 8 Threads model i7-4870HQ @ 2.50GHz.
Intel Iris Pro GPU with Built-in Bus, VRAM 1.5 GB, Display 2880 x 1800 Retina, 24-Bit color.
macOS Monterey; browsers: Waterfox "Current", Vivaldi and (now and then) Chrome; security apps. Intego AV

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Alex5723 wrote:

is it still there ?

Why don’t you pop over and check? While you are there you can do a quick review for us.
We promise to still be here when you get back.

cheers, Paul

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I am waiting for the Enterprise (or Mask’s Space X) to touch down near by So as to jump to the new/old Alcyoneus galaxy.

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If I were you, Alex I’ll just sit and quietly wait for 3,000,000,000 years. That’s a lot easier and more likely to work: trust me. I know.

Ex-Windows user (Win. 98, XP, 7); since mid-2017 using also macOS. Presently on Monterey 12.15 & sometimes running also Linux (Mint).

MacBook Pro circa mid-2015, 15" display, with 16GB 1600 GHz DDR3 RAM, 1 TB SSD, a Haswell architecture Intel CPU with 4 Cores and 8 Threads model i7-4870HQ @ 2.50GHz.
Intel Iris Pro GPU with Built-in Bus, VRAM 1.5 GB, Display 2880 x 1800 Retina, 24-Bit color.
macOS Monterey; browsers: Waterfox "Current", Vivaldi and (now and then) Chrome; security apps. Intego AV

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Alex5723

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