Astronomers Catch Wind Rushing Out of Galaxy (phys.org) 31
A group of astronomers have found direct evidence for the first time of the role of galactic winds -- ejections of gas from galaxies -- in creating the circumgalactic medium (CGM). "It exists in the regions around galaxies, and it plays an active role in their cosmic evolution," reports Phys.Org. "The unique composition of Makani -- meaning wind in Hawaiian -- uniquely lent itself to the breakthrough findings." From the report: "Makani is not a typical galaxy," noted [UC San Diego's Alison Coil], a physics professor at UC San Diego. "It's what's known as a late-stage major merger -- two recently combined similarly massive galaxies, which came together because of the gravitational pull each felt from the other as they drew nearer. Galaxy mergers often lead to starburst events, when a substantial amount of gas present in the merging galaxies is compressed, resulting in a burst of new star births. Those new stars, in the case of Makani, likely caused the huge outflows -- either in stellar winds or at the end of their lives when they exploded as supernovae." Coil explained that most of the gas in the universe inexplicably appears in the regions surrounding galaxies -- not in the galaxies. Typically, when astronomers observe a galaxy, they are not witnessing it undergoing dramatic events -- big mergers, the rearrangement of stars, the creation of multiple stars or driving huge, fast winds.
Coil and [Rhodes College's David Rupke], the paper's first author, used data collected from the W. M. Keck Observatory's new Keck Cosmic Web Imager (KCWI) instrument, combined with images from the Hubble Space Telescope and the Atacama Large Millimeter Array (ALMA), to draw their conclusions. The KCWI data provided what the researchers call the "stunning detection" of the ionized oxygen gas to extremely large scales, well beyond the stars in the galaxy. It allowed them to distinguish a fast gaseous outflow launched from the galaxy a few million year ago, from a gas outflow launched hundreds of millions of years earlier that has since slowed significantly. From the Hubble, the researchers procured images of Makani's stars, showing it to be a massive, compact galaxy that resulted from a merger of two once separate galaxies. From ALMA, they could see that the outflow contains molecules as well as atoms. The data sets indicated that with a mixed population of old, middle-age and young stars, the galaxy might also contain a dust-obscured accreting supermassive black hole. This suggests to the scientists that Makani's properties and timescales are consistent with theoretical models of galactic winds. The findings have been published in the journal Nature.
Coil and [Rhodes College's David Rupke], the paper's first author, used data collected from the W. M. Keck Observatory's new Keck Cosmic Web Imager (KCWI) instrument, combined with images from the Hubble Space Telescope and the Atacama Large Millimeter Array (ALMA), to draw their conclusions. The KCWI data provided what the researchers call the "stunning detection" of the ionized oxygen gas to extremely large scales, well beyond the stars in the galaxy. It allowed them to distinguish a fast gaseous outflow launched from the galaxy a few million year ago, from a gas outflow launched hundreds of millions of years earlier that has since slowed significantly. From the Hubble, the researchers procured images of Makani's stars, showing it to be a massive, compact galaxy that resulted from a merger of two once separate galaxies. From ALMA, they could see that the outflow contains molecules as well as atoms. The data sets indicated that with a mixed population of old, middle-age and young stars, the galaxy might also contain a dust-obscured accreting supermassive black hole. This suggests to the scientists that Makani's properties and timescales are consistent with theoretical models of galactic winds. The findings have been published in the journal Nature.
Answer to the big questions! (Score:4, Funny)
Looks like we've finally answered one the burning questions of our time: Do galaxies fart?
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Isn't there a cartoon where the big bang literally comes out as one of God's farts?
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God farting, sneezing, or ejaculating out a universe is a fairly common subject in cartoons. It's not really a huge leap from "Big Bang" to explosive bodily functions.
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...and do those farts contribute to galactic warming?
Whilst said in jest, I'll bet someone few hundred years ago heard a cow fart and thought "ha - that's funny". Here we are many years later realising that cow farts have a part to play in our environmental problems. What if in 500 years, we figure out that causes galactic farts and they have an effect on ?
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... I assume Slashdot's commentariat is maturing...
No. No it isn't.
Dark matter? (Score:3)
Could this be the explanation for "dark matter"? ie. There's a lot more intergalactic gas than we suspected?
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Usually there's the wind, then the dark matter follows.
Re: Dark matter? (Score:2)
No.
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No. We already knew there was gas surrounding galaxies, but not in the galaxies, and had theories about how and why it was there. This is the first time we've seen the process while it was happening.
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If there were enough normal matter in galactic halos to make up fo the missing Dark Matter the resulting cloud would be dense enough to obscure much of the light from the galaxy. That's why they call it "dark", because it's transparent to photons and can't be illuminated.
So, a Ramscoop might be viable? (Score:2, Interesting)
To travel between galaxies, since that's where all the fuel is?
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Nice non-explanation. Now can anyone else do more than provide punditry?
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No more or less so than it was before this was seen. We already knew that galaxies are often surrounded by gas. This is just the first chance we've had to observe how that gas gets there.
That's not what happened (Score:3)
When the two galaxies merged, the politicians in both galaxies merged and the enormous outflow of gas is just witness to this event.
Link broken in TFS, here's phys.org (Score:5, Informative)
The link in first sentence of summary was probably meant to be to this page:
- "Astronomers catch wind rushing out of galaxy" [phys.org], October 31, 2019
No need for Dark Matter then? (Score:1)
So, no need to invoke Dark Matter to explain the evolution of galaxies?
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There's not nearly enough gas to make up the difference, so yeah, Dark Matter is still in play. If the mass accredited to Dark Matter were actually normal matter spread around thinly the universe would be pretty much opaque. That's how much mass we're missing.
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Near the outer-edge of a galaxy it's enough to impart a twisting s shaped wave to the galaxy and so maintain the 'spokes' necessary for star formation. There's a name for this non-dark-matter theory which I'm too lazy to look up at the moment.
You don't want to ... (Score:2)
... catch the wind coming out of my galaxy ...
Ba-dum ching!
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*ching*?
I think your drums are broken mate.
Re: You don't want to ... (Score:2)
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Cymbals go tsssss. Budump-tssss. If your cymbal goes "ching" your drum machine may be infected with Chinese malware.
https://www.youtube.com/watch?... [youtube.com]
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Cymbals go tsssss. Budump-tssss. If your cymbal goes "ching" your drum machine may be infected with Chinese malware.
https://www.youtube.com/watch?... [youtube.com]
Yes. The malware is called iChing.
been there seen that (Score:2)
Data in the Cloud (Score:2)
This is a benefit that I never foresaw when they first started talking about cloud computing; the ability to easily combine disparate data sets that would otherwise have been in silos scattered around the world. Very cool.
The Restaurant at the End of the Universe (Score:2)
In other news, I've caught.... (Score:1)
...wind rushing out of my ass.