Milky Way's origins are not what they seem

July 27, 2017, Northwestern University
Pair of nearby galaxies with possible intergalactic transfer: This image shows M81 (bottom right) and M82 (upper left), a pair of nearby galaxies where 'intergalactic transfer' may be happening. Gas ejected by supernova explosions in M82 can travel through space and eventually contribute to the growth of M81. Credit: Fred Herrmann, 2014, cs.astronomy.com/asy/m/galaxies/489483.aspx

In a first-of-its-kind analysis, Northwestern University astrophysicists have discovered that, contrary to previously standard lore, up to half of the matter in our Milky Way galaxy may come from distant galaxies. As a result, each one of us may be made in part from extragalactic matter.

Using supercomputer simulations, the research team found a major and unexpected new mode for how galaxies, including our own Milky Way, acquired their : intergalactic transfer. The simulations show that supernova explosions eject copious amounts of gas from galaxies, which causes atoms to be transported from one galaxy to another via powerful . Intergalactic transfer is a newly identified phenomenon, which simulations indicate will be critical for understanding how galaxies evolve.

"Given how much of the matter out of which we formed may have come from other galaxies, we could consider ourselves space travelers or extragalactic immigrants," said Daniel Anglés-Alcázar, a postdoctoral fellow in Northwestern's astrophysics center, CIERA (Center for Interdisciplinary Exploration and Research in Astrophysics), who led the study. "It is likely that much of the Milky Way's matter was in other galaxies before it was kicked out by a powerful wind, traveled across intergalactic space and eventually found its new home in the Milky Way."

Galaxies are far apart from each other, so even though galactic winds propagate at several hundred kilometers per second, this process occurred over several billion years.

Professor Claude-André Faucher-Giguère and his research group, along with collaborators from the FIRE ("Feedback In Realistic Environments") project, which he co-leads, had developed sophisticated numerical simulations that produced realistic 3-D models of galaxies, following a galaxy's formation from just after the Big Bang to the present day. Anglés-Alcázar then developed state-of-the-art algorithms to mine this wealth of data and quantify how galaxies acquire matter from the universe.

A Milky Way-like galaxy (Messier 101): A close-up view of the Messier 101 galaxy, which is a spiral galaxy similar to the Milky Way galaxy. The Messier 101 has a pancake-like shape that we view face-on. This perspective shows off the spiral structure that gives it the nickname the "Pinwheel Galaxy." Credit: NASA

The study, which required the equivalent of several million hours of continuous computing, will be published July 26 (July 27 in the U.K.) by the Monthly Notices of the Royal Astronomical Society.

"This study transforms our understanding of how galaxies formed from the Big Bang," said Faucher-Giguère, a co-author of the study and assistant professor of physics and astronomy in the Weinberg College of Arts and Sciences.

"What this new mode implies is that up to one-half of the atoms around us—including in the solar system, on Earth and in each one of us—comes not from our own galaxy but from other galaxies, up to one million light years away," he said.

By tracking in detail the complex flows of matter in the simulations, the research team found that gas flows from smaller galaxies to larger galaxies, such as the Milky Way, where the gas forms stars. This transfer of mass through galactic winds can account for up to 50 percent of matter in the larger galaxies.

"In our simulations, we were able to trace the origins of stars in Milky Way-like galaxies and determine if the star formed from matter endemic to the galaxy itself or if it formed instead from gas previously contained in another galaxy," said Anglés-Alcázar, the study's corresponding author.

This is an animation of gas flows during Milky Way-like galaxy formation: This animation shows the complex gas flows participating in the formation of a Milky Way-like galaxy, as seen in the FIRE simulations. Face-on (left) and edge-on (right) views are shown. Credit: Philip Hopkins, Caltech

In a galaxy, stars are bound together: a large collection of stars orbiting a common center of mass. After the Big Bang 14 billion years ago, the universe was filled with a uniform gas—no stars, no galaxies. But there were tiny perturbations in the gas, and these started to grow by force of gravity, eventually forming stars and galaxies. After formed, each had its own identity.

"Our origins are much less local than we previously thought," said Faucher-Giguère, a CIERA member. "This study gives us a sense of how things around us are connected to distant objects in the sky."

The findings open a new line of research in understanding galaxy formation, the researchers say, and the prediction of intergalactic transfer can now be tested. The Northwestern team plans to collaborate with observational astronomers who are working with the Hubble Space Telescope and ground-based observatories to test the predictions.

The simulations were run and analyzed using the National Science Foundation's Extreme Science and Engineering Discovery Environment supercomputing facilities, as well as Northwestern's Quest high-performance computer cluster.

The study is titled "The Cosmic Baryon Cycle and Galaxy Mass Assembly in the FIRE Simulations."

Explore further: Galactic winds slow new star formation

More information: The Cosmic Baryon Cycle and Galaxy Mass Assembly in the FIRE Simulations arXiv:1610.08523 [astro-ph.GA] arxiv.org/abs/1610.08523

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joel in oakland
3.6 / 5 (7) Jul 27, 2017
"...up to half of the matter in our Milky Way galaxy may come from distant galaxies."

A million light years is only half the distance to Andromeda. Galaxies within that distance are all satellites of ours.

Guess it depends on one's idea of "distant galaxies."
Dingbone
Jul 27, 2017
This comment has been removed by a moderator.
Dingbone
Jul 27, 2017
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Da Schneib
4.5 / 5 (8) Jul 27, 2017
"...up to half of the matter in our Milky Way galaxy may come from distant galaxies."

A million light years is only half the distance to Andromeda. Galaxies within that distance are all satellites of ours.

Guess it depends on one's idea of "distant galaxies."
@Joel, from the article:
Galaxies are far apart from each other, so even though galactic winds propagate at several hundred kilometers per second, this process occurred over several billion years.

Benni
1 / 5 (5) Jul 27, 2017
"...up to half of the matter in our Milky Way galaxy may come from distant galaxies."

A million light years is only half the distance to Andromeda. Galaxies within that distance are all satellites of ours. Guess it depends on one's idea of "distant galaxies."


@Joel, from the article: Galaxies are far apart from each other, so even though galactic winds propagate at several hundred kilometers per second, this process occurred over several billion years.


Schneibo, learn to do some simple math.

Andromeda is only 2.5 million light years distance. It was already suspected a decade ago that the VM halo of the two galaxies overlapped one another, this study by Faucher-Giguère simply establishes that fact, that over the course of billions of years that galactic winds traveling at a velocity of several hundred kilometers per second have easily carried REAL detectable matter over that relatively short distance.
691Boat
5 / 5 (5) Jul 27, 2017

Schneibo, learn to do some simple math.

Andromeda is only 2.5 million light years distance. It was already suspected a decade ago that the VM halo of the two galaxies overlapped one another, this study by Faucher-Giguère simply establishes that fact, that over the course of billions of years that galactic winds traveling at a velocity of several hundred kilometers per second have easily carried REAL detectable matter over that relatively short distance.


@Benni: Other than repeating what was already posted in the article, not sure what your point is. At 300km/s, travelling 2.5mly will take 2.5 billion years, so where was Da Schneib wrong?
RealityCheck
1 / 5 (3) Jul 27, 2017
@691Boat (and Dingbone, RNP, IMP-9 et al if you are reading. :)

Do you recall my longstanding observations re the universally ubiquitous polar-jet, galactic wind processes effectively *recycling* (de-constructing/re-constructing) and effectively *re-distributing* energy-matter all over the place into deep space, to effectively *re-form* into seemingly *pristine* and *mixed state/metallicity* looking nebulae, streams, stars, stellar-clusters, galaxies/satellite-galaxies/clusters over BILLIONS of years and over the epochs of a continuous eternal/infinite Recycling Universal process?

It's good to know, isn't it, that the mainstream astronomers/cosmologists are finding out the obvious that I have been pointing out for so many years while being insulted and called "liar" by so many of the bot-voting troll gang here.

Do you think that CS-gang will ever end their denial, and just admit I've been correct all along, on many fronts, both science and behavior?

Cheers all!. :)
Uncle Ira
5 / 5 (3) Jul 27, 2017
@ Really-Skippy. How you are Cher? I am good, thanks for asking.

I think you are fibbing again Skippy.
Do you recall my longstanding observations
Cher, we all know you don't have the kind of telescope you need to observe those things. You never did have before either. So if you been observing the "ubiquitous polar-jet, galactic wind processes", how you can do that effectively without a telescope?

Unless you get a real telescope or a real laboratory it is going to be hard to convince us that you have done any real observing. Oh yeah, I almost forget. It would also help if you went to a real science school before you buy one of those because you need some serious training to know how to use him and know what you are observing too..

Cheery is me matey. (How you like me now Cher?)

RealityCheck
2 / 5 (4) Jul 27, 2017
@Uncle Ira.
Do you recall my longstanding observations
Cher, we all know you don't have the kind of telescope you need to observe those things. You never did have before either. So if you been observing the "ubiquitous polar-jet, galactic wind processes", how you can do that effectively without a telescope?
I used "observations" advisedly; in context of "noting" the implications of cosmology/astronomy data already collected/analyzed by mainstream telescopes whose data is publicly available for study and consequential observations re what the data indicates is occurring. English Usages of this terma also includes this one:
"a remark, statement, or comment based on something one has seen, heard, or noticed"
So you just learned something, Ira. Good. :)
How you like me now Cher?
About as much as an intelligent correct-on-science poster (me) can "like" a bot-voting ignoramus (you) being stupid/malicious/irrelevant on a science news/discussion site, Ira. :)
Da Schneib
5 / 5 (3) Jul 27, 2017
@Ira, not to mention this article isn't about mass ejection from the galactic core but from supernovae in the disk. Says so right in the paper.
RealityCheck
1 / 5 (3) Jul 27, 2017
@Da Schneib.
@Ira, not to mention this article isn't about mass ejection from the galactic core but from supernovae in the disk. Says so right in the paper.
You must be REALLY obtuse/dishonest not to realize the SUBSTANTIVE WIDER POINT: ALL the ways that de-constructed material is ejected into deep space reaches to reform 'pristine looking' and 'mixed state/metallicity' looking features like nebulae, stars etc etc; as I pointed out happens all over at all scales due to the various 'recycling' processes, of which galactic etc polar 'jets' and supernovae 'winds' are the main ones.

No wonder all you are good for is to parrot obvious orthodoxy, DS; you cannot (or will not) CONNECT THE DOTS for yourself; even when I present them all to you on a silver platter! You exhibit everything that is wrong with TOO MANY 'science' theory/journalist HACKS who go along with OTHER HACKS who have run the peer-review and grants/employment system for the closed-shop TWITS/HACKS.

Pitiable.
richk
not rated yet Jul 27, 2017
what/is/the/source/of/the/galactic/winds
and
is/the/matter/transferred/only/nova/ejector
RealityCheck
2.3 / 5 (3) Aug 02, 2017
@bschott.
We have observed a total of 1 supernova in the Andromeda galaxy, our nearest neighbor.
up to half of the matter in our Milky Way galaxy may come from distant galaxies

Glad they used the word "may", because if half the visible matter in our galaxy got here due to SN's from other galaxies...the universe is a lot older than estimated given the time required for that mass to get here and our galaxy to form. Or the SN hypothesis as the spreader of matter is just wrong.
Well observed, bschott. :)

Curious; it's been almost a week, yet @DS, @CS, @antialias, @RNP, @IMP-9, @jonesdave, @UI et al have NOT seen fit to either:

- ridicule you;

- or address implications in your above observations which support Eternal, Infinite, Recycling/Redistributing Universal scenario, NOT the now-falsified BB etc.

What could be keeping them from kneejerking to ridicule you in this instance, bschott? Maybe they're realizing they were wrong all along? Just maybe? :)
Uncle Ira
5 / 5 (3) Aug 02, 2017
@ Really-Skippy. How you are Cher? I am good me, thanks for asking.

@UI et al have NOT seen fit to either:
Why you want to drag me into this for? I am not the one who falsified you, you done that all by your own self.

Just what it is you want me to see and be fit enough to do?

The above observations are already in the early universes theories. You act like that is some great new question that nobody ever thought of before. The professional real scientists (like you are not) answered that question a long time ago and if you were keeping up you would know about that.
RealityCheck
1 / 5 (2) Aug 02, 2017
@Uncle Ira.
Why you want to drag me into this for?
You "dragged" yourself into it with your first post trolling/insulting etc what you didn't comprehend, Ira. And then @DS "kept dragging you" when he 'rode' on your trolling post to make his own uncomprehending remarks. You two are the "drag buddies" in this instance, Ira.
I am not the one who falsified you, you done that all by your own self. Just what it is you want me to see and be fit enough to do?
I haven't been "falsified" at all, Ira; either by you or your "drag buddy", DS. So far, you are 'fit for nothing' but bot-voting in ignorance, Ira.
The above observations are already in the early universes theories.
Your incomprehension continues unabated, @Ira; you missed @bschott's (and my) point that the article's implications militate AGAINST the mere 14-BILLION year ONLY universal 'beginning/timeline' claimed by your "professional real scientists", so it further falsifies BB/Inflation etc fantasy. :)
Uncle Ira
5 / 5 (3) Aug 02, 2017
I haven't been "falsified" at all
Yeah Cher you have been falsified all along. You do not have to take my word for it. Ask anybody how you have been proven falsified all along.

Everybody you ever argued with on the physorg has falsified you all along. Choot, I bet you can not name one person who says you are not falsified.

You just mad because DaSchneib-Skippy falsified your lies you keep telling.

And the Captain-Skippy made you mad because he told everybody about you having the criminal records.

And Anti-Skippy for falsifying your toes and everything.

And me-Skippy for falsifying your pretend scientist laboratory you call the Earthman Playhouse.

And a bunch of other Skippys falsified you too but I don't have enough letter spaces to list them all, and it would take about a year to list them even if I did have the spaces.

You been falsified every day you ever came here Cher, you been falsified all along.
RealityCheck
1 / 5 (2) Aug 02, 2017
@Uncle Ira.
Yeah Cher you have been falsified all along. You do not have to take my word for it. Ask anybody how you have been proven falsified all along.
Everybody you ever argued with on the physorg has falsified you all along. Choot, I bet you can not name one person who says you are not falsified.
You just mad because DaSchneib-Skippy falsified your lies you keep telling.
And the Captain-Skippy made you mad because he told everybody about you having the criminal records.
And Anti-Skippy for falsifying your toes and everything.
And me-Skippy for falsifying your pretend scientist laboratory you call the Earthman Playhouse.
And a bunch of other Skippys falsified you too but I don't have enough letter spaces to list them all, and it would take about a year to list them even if I did have the spaces.
You been falsified every day you ever came here Cher, you been falsified all along.
...an all 'cos a Bot-Voting Ignoramus says so! You're a funny 'twitbot', Ira.
RealityCheck
Aug 02, 2017
This comment has been removed by a moderator.
RealityCheck
1 / 5 (2) Aug 07, 2017
@Moderator. Re above post removal. Yes, it was unnecessary to point out yet again who the 'falsified' posters actually were. Cheers. :)

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