Its a classic Halloween tale.
A group of ghost hunters visit a grand old house that is rumoured to be haunted.
But after thoroughly exploring, they leave disappointed: there are no ghosts to be seen.
It was there all the time.
The finding has huge significance because it demonstrates how chemical elements mix on very large scales around galaxies.
Baryonic matter is normal everyday matter, such as carbon.
So were intimately connected to the stuff.
Imagine you could put all the baryons in the universe into a jar.
Now pick one of those particles at random.
Where do you think it would have come from?
The answer is surprising to most: its likely that baryon would have come from the spacebetweengalaxies.
Most of the normal matter in the universe isnt contained within galaxies at all.
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Large-Scale simulation of the distribution of gas in the universe.
Galaxies form at the dense nodes of the cosmic web drive outflows of gas back into the circumgalactic medium.
Jim Geach & Rob Crain
We call itthe cosmic web.
At the densest points of the web, galaxies formed.
Other elements were formed in cataclysmic stellar explosions.
Without such mixing, you wouldnt exist.
We are all what the baddies in Harry Potter may call cosmic mudbloods.
These winds transport heavy elements formed in galaxies out into the CGM.
Some of these elements will later rain back down, perhaps to be incorporated in new solar systems.
Others will spend the rest of eternity exiled in intergalactic space.
Computer simulations show this process in beautiful detail.
The instrument, based in Hawaii, is no ordinary camera.
It measures thespectrumof light collected by the telescope, dispersing the light into its different frequencies, or colours.
This allows us to see much more than would otherwise be possible with a traditional imaging camera.
They are also extremely compact compared to most galaxies.
We think that most of them formed from the collision of two galaxies that have now coalesced into one.
A volume rendering of the KCWI data, revealing the huge Makani nebula and fast outflow.
We expected to detect something, but what we saw really surprised us.
This glowing nebula dwarfs the central galaxy, but without KCWI you wouldnt know it was there.
Theres nothing paranormal going on here though.
From the color or frequency, of the light, we know it is being emitted by oxygen ions.
Our initial analysis shows that the properties of the outflow broadly agree with predictions from theory.
We now havetheideal system to study the process, and can use this data to refine the models.
Whats needed now is more examples of objects like Makani.
