Universe's early galaxies grew massive through collisions

Jan 29, 2014
Universe's early galaxies grew massive through collisions
This graphic compares the size of the extremely compact dead galaxies in the early universe with the size of our own galaxy, the Milky Way. The two galaxy types have approximately equal amounts of stars, which means that the density of stars in the compact galaxies is more that 10 times higher than in the Milky way. The researchers have now discovered how these extreme galaxies formed. Credit: NASA, European Space Agency, and S. Toft og A. Feild

It has long puzzled scientists that there were enormously massive galaxies that were already old and no longer forming new stars in the very early universe, approx. 3 billion years after the Big Bang. Now new research from the Niels Bohr Institute, among others, shows that these massive galaxies were formed by explosive star formation that was set in motion by the collision of galaxies a few billion years after the Big Bang. The results are published in the scientific journal, Astrophysical Journal.

Galaxies are giant collections of stars, and dark matter. The smallest galaxies contain a few million stars, while the largest can contain several hundred billion stars. The first stars already emerged in the very early universe approx. 200 million years after the Big Bang from the gases hydrogen and helium. Gas is the raw material used to form stars. These giant clouds of gas and dust contract and eventually the gas is so compact that the pressure heats the matter so that glowing gas balls are formed, new stars are born. The stars are collected in galaxies, the first of which are a kind of baby galaxies. As long as there is gas in the galaxy, new stars are being formed.

Mysteries in the childhood of the universe

The astronomers' theory is therefore that the structure of the universe was built by baby galaxies gradually growing larger and more massive by constantly forming new stars and by colliding with neighbouring galaxies to form new, larger galaxies. The largest galaxies in today's universe were therefore believed to have been under construction throughout the history of the universe.

This graphic shows the evolutionary sequence in the growth of massive elliptical galaxies over 13 billion years, as gleaned from space-based and ground-based telescopic observations. The growth of this class of galaxies is quickly driven by rapid star formation and mergers with other galaxies. Credit: NASA, ESA, S. Toft (Niels Bohr Institute), and A. Feild (STScI)

"That is why it surprised us that we already when the universe was only 3 billion years old, found galaxies that were just as massive as today's large spiral galaxies and the largest , which are the giants in the local universe. Even more surprisingly, the stars in these early galaxies were squeezed into a very small area, so the size of the galaxies were three times smaller than similar mass galaxies today. This means that the density of stars was 10 times greater. Furthermore, the galaxies were already dead, so they were no longer forming new stars. It was a great mystery," explains Sune Toft, Dark Cosmology Centre at the Niels Bohr Institute at the University of Copenhagen.

The extremely massive and compact galaxies were not flattened spiral galaxies where stars and gas rotate around the centre. Rather, they resembled elliptical galaxies where stars move more hither and thither and where the gas for new star formation has been used up. But how could the galaxies become so massive and so burnt out so early? How were they formed?

Solving the mystery

To find out what happened, Sune Toft had to look even further back in time. Based on the ages of the galaxies, he knew that they had to have formed very early in the history of the universe, but at that point there was simply not enough time for the galaxies to have grown so massive through normal star formation. He had a theory that the were formed by the fusion of smaller galaxies, but that alone could not explain how they had become so massive so quickly and were already dead. The theory was therefore, that there must have been some especially extreme galaxies in the formation process.

"We studied the galaxies that existed when the universe was between 1 and 2 billion years old. My theory that it must have been some galaxies with very specific properties that were part of the formation process made me focus on the special SMG galaxies, which are dominated by intense stare formation hidden under a thick blanket of dust," explains Sune Toft.

He explains that when such gas-rich galaxies merge, all of the gas is driven into the centre of the system where it ignites an explosion of new star formation. A lot of are formed in the centre and the galaxy quickly becomes very compact. But with the explosive , the gas to form is also used up extremely quickly and then you get a dead galaxy.

"I discovered that there was a direct evolutionary link between two of the most extreme galaxy types we have in the universe – the most distant and most intense star forming galaxies which are formed shortly after the Big Bang – and the extremely compact dead galaxies we see 1-2 billion years later," says Sune Toft.

The new research is a breakthrough in discovering the formation process of the enormously massive and dead in the early .

Explore further: Galactic star 'baby boom' ended five billion years ago

More information: The results appear in the Jan. 29 online issue of The Astrophysical Journal dx.doi.org/10.1088/0004-637X/782/2/68 , preprint: arxiv.org/abs/1401.1510

Related Stories

Galactic star 'baby boom' ended five billion years ago

Jan 16, 2014

Luminous galaxies far brighter than our Sun constantly collide to create new stars, but Oxford University research has now shown that star formation across the Universe dropped dramatically in the last five ...

Astronomers gain new knowledge about early galaxies

Jul 03, 2013

The early galaxies of the universe were very different from today's galaxies. Using new detailed studies carried out with the ESO Very Large Telescope and the Hubble Space Telescope, researchers, including ...

Early universe was less dusty than believed

Dec 09, 2013

(Phys.org) —Dust may be more rare than expected in galaxies of the early Universe, according to an international research team, led by Swinburne University of Technology astrophysicist Dr David Fisher.

Hubble catches the moment the lights went out

Feb 06, 2013

(Phys.org)—The further away you look, the further back in time you see. Astronomers use this fact to study the evolution of the Universe by looking at nearby and more distant galaxies and comparing their ...

Recommended for you

The Great Cold Spot in the cosmic microwave background

Sep 19, 2014

The cosmic microwave background (CMB) is the thermal afterglow of the primordial fireball we call the big bang. One of the striking features of the CMB is how remarkably uniform it is. Still, there are some ...

Mystery of rare five-hour space explosion explained

Sep 17, 2014

Next week in St. Petersburg, Russia, scientists on an international team that includes Penn State University astronomers will present a paper that provides a simple explanation for mysterious ultra-long gamma-ray ...

User comments : 17

Adjust slider to filter visible comments by rank

Display comments: newest first

Tuxford
1 / 5 (6) Jan 29, 2014
Confusing explanation from another confused astronomer indulging in fanciful musings of merger mania, despite the evidence he directly confronts. Indeed, with galaxies growing from the inside out, like a plant from a seed, the density of the core is naturally greater than the expanding outskirts. Gosh, these guys really can't think well, despite all that education.

http://phys.org/n...tly.html

http://phys.org/n...ays.html

http://phys.org/n...ung.html

http://phys.org/n...tml#nRlv

http://phys.org/n...ace.html

http://phys.org/n...tml#nRlv

yyz
5 / 5 (4) Jan 29, 2014
"...with galaxies growing from the inside out, like a plant from a seed, the density of the core is naturally greater than the expanding outskirts."

Following that logic, these 2 galaxies are, what, growing from the outside in?

http://en.wikiped..._all.jpg

http://en.wikiped..._147.jpg

Are the densities of their cores greater than their expanding outskirts?

Where's the seed of that plant again?
Tuxford
1 / 5 (5) Jan 29, 2014
I once asked about similar structures. I believe LaViolette would explain that the ring-like structures are often result from a massive superwave of cosmic radiation projecting from the core, illuminating the nebulas via synchrotron radiation, much like the crab nebula today is illuminated from the superwave that passed Earth during the last ice age. So the inner part of galaxies are no longer illuminated, as the superwave has already passed. Hence, the ring.

But I suspect that some cores just grow so active that stars can no longer form in the inner regions, so stars migrate to the outskirts leaving the inner regions largely vacant, at least in some cases. But the latter is simply my musings. We need those fanciful astronomers to get busy on proper confirmations, rather than focusing on merger mania.
Nestle
1 / 5 (1) Jan 29, 2014
these massive galaxies were formed by explosive star formation that was set in motion by the collision of galaxies a few billion years after the Big Bang
The problem of this explanation is, the distant galaxies are not only mature, but already pretty distant each other. There is no indication of galactic mergers or increased density of galaxies inside of Hubble deep field, for example and the Universe appears isotropic there.
a direct evolutionary link between two of the most extreme galaxy types we have in the universe – the most distant and most intense star forming galaxies which are formed shortly after the Big Bang – and the extremely compact dead galaxies we see 1-2 billion years later
These "most intense star forming galaxies" weren't observed yet, so that it's the explanation of non existing phenomena, i.e. speculation, the only purpose of which is to save the Big Bang cosmology against flaws in logics.
yyz
5 / 5 (6) Jan 30, 2014
"There is no indication of galactic mergers or increased density of galaxies inside of Hubble deep field, for example and the Universe appears isotropic there."

What a strange (and incorrect) claim Zephyr. There are many studies of merging galaxies in the Hubble Deep Field(s) -

HUDF:
http://arxiv.org/abs/0712.0416

http://arxiv.org/abs/0711.2333

From the second paper: "We furthermore calculate the merger rate of galaxies in the UDF up to z~3, finding an increase with redshift as well as stellar mass, confirming previous work in the Hubble Deep Field."

HDF:
http://arxiv.org/.../9602044

From the abstract: "The steeply rising number count-magnitude relation for irregular/peculiar/merging systems at I<22 mag reported in Glazebrook \etal\ (1995a) continues to at least I=25 mag."

I'd say there's a lot of evidence for galaxy mergers in the Deep Fields and their numbers increase with redshift, contrary to your unsupported statement.
antialias_physorg
5 / 5 (6) Jan 30, 2014
C'mon yyz...you can't go around confusing people with facts. Where would we get to in science if people cared about that? Pshaw.
Fleetfoot
5 / 5 (1) Jan 31, 2014
"The first stars already emerged in the very early universe approx. 200 million years after .."

That is somewhat inaccurate too, generally a figure of ~100 million is quoted based on early simulations but in 2006, Naoz a value of ~30 million years was suggested by Naoz:

http://arxiv.org/.../0604050
Eternalflame
1 / 5 (3) Jan 31, 2014
Space dont expanding!

Space is eternal and infinity place "who" is nothing!

Space dont be dynamics at all!

Light expanding and light is from nucleus of atoms "who" also expanding!

Expanding nucleus of atoms are from expanding galaxys nucleus supermassive and very density concentrations!

Galaxys centres supermassive concentration are from one level more massive and more density concentration "who" is outside visible universe!

galaxys born inside to outside!

Onesimpleprinciple
Eternalflame
1 / 5 (2) Jan 31, 2014
Visible universe expanding densers RECYCLING EXPANDING THING all a time and thats why that expanding thing changing with time.

Same expanding quark, different expanding thing

Same expanding lake, other / different expanding water

Same expanding photon, different / other expanding thing!

Expanding light get expanding light expanding faster and faster!

Expanding material get expanding material expanding faster and faster!

Space dont expanding at all!

.
Captain Stumpy
5 / 5 (1) Jan 31, 2014
Space dont expanding at all!

@Eternalflame
the above is the only thing I understood in your posts
it is also an assumption that does NOT match observed evidence
look at the following link... read the WHOLE page... but especially pay attention to the "observational evidence" section

http://en.wikiped...evidence

your other claims are not understood... but they might be should you provide links/proof/evidence for your assumptions

thanks
Eternalflame
1 / 5 (2) Jan 31, 2014
Have you ever see how space expanding?

Do you know how and why space expanding?

No, you dont ever see how space expanding and you cant explain why and how space expanding!

Have you ever see how star expanding like supernova? Yes!

Have you ever see how nucleusbomb expanding? Yes!

Why is so difficult understund, that all quarks expanding and recycling all a time expanding stuff?

Why light start expanding faster and faster same time when born quasars and when more and more light start moving all direction?

What about if light expanding? Not space?

.
Osteta
Jan 31, 2014
This comment has been removed by a moderator.
antialias_physorg
5 / 5 (3) Jan 31, 2014
In this moment the non Big Bang scenarios are just a matter of few extreme theorists, but the number of these studies increases rapidly.

So? Once one of them makies a testable prediction we'll all go check. If it turns out that that theory is better than the Big Bang then it will be the new standard theory. That's how science works.
Will any scientis then clamor to save the "Big Bang" if it's testably not the best theory? No. Why should they? You make it out that some people have an investment in their theory. Why? That's not how science works.

BTW: The 'number of studies' for/against anything has nothing to do with it.

Changing mass/changing speed of light is just like epicycles. Sure you can make those theories (and like epicycles they are just as valid!). But But with equivalent predictive power we go for the simplest one (which currently is Big Bang an constant mass/light speed)
Osteta
Jan 31, 2014
This comment has been removed by a moderator.
Osteta
Jan 31, 2014
This comment has been removed by a moderator.
Tuxford
1 / 5 (4) Jan 31, 2014
[....will anounce, that the Big Bang did never happen


What? No Huge Bang Fantasy? Where will we send all the certain defenders who have been slamming me for the last few years? Disneyland? Nice place for children. But not sure Mickey would be very happy with this new crew!
jewelblade
1 / 5 (3) Feb 02, 2014
What the hell is intersubjective, and why did you say Holy Church without "the" and why do you lump in all opposition to the Catholic church as not holy, but sectarian? You apparently, have, from your pointless fancy talk and extreme contempt and arrogance for those who disagree with the false gospel of the Catholic SECT, narcissistic personality disorder. The Cath sect is a cult, it is an idolatrous cult that worships man, prays to the dead, worships angels and Mary and the Pope and turns Jesus into an effeminate white man, similar to how the Mormons make him into a white red neck, that holds tradition higher than God's word. That cult is clearly going to Hell. Salvation cannot be earned, and yes cultists: not everyone can have the Holy Spirit, and THAT DOES ABSOLUTELY INCLUDE YOUR CULT. It's those who realize this and love God, who don't reject his free gift of salvation and don't try and earn credit for their salvation, that have the Spirit.
jewelblade
1 / 5 (3) Feb 02, 2014
Can you spot the logical fallacy?:

"It has long puzzled scientists that there were enormously massive galaxies that were already old and no longer forming new stars in the very early universe, approx. 3 billion years after the Big Bang. Now new research from the Niels Bohr Institute of Baloney, among others, shows that these massive galaxies were formed by explosive star formation that was set in motion by the collision of galaxies a few billion years after the Big Bang, because creationists and the Bible just cannot be right, this is because the Big Bang is true, because? "Because?" Huh? There is no because! Creationists and the Bible just cannot be right dammit! Stop asking us that question!!! What are you a Christian!? A conservative? Constitutionalist tea bagger mass murdering nutjob!? You believe sky daddies don't you you abortion-hating homophobe!!! The results of this circular reasoning are published in the oh so scientific journal: the (Liberal) Astrophysical Journal.
TheGhostofOtto1923
1 / 5 (1) Feb 02, 2014
What the hell is intersubjective
The internet is for looking things UP.

in·ter·sub·jec·tive/
adjective
Philoblah
1. existing between conscious minds; shared by more than one conscious mind.
why do you lump in all opposition to the Catholic church as not holy... the false gospel of the Catholic SECT
Ahaahaaaa it always cracks me up when religionists play holier-than-thou.
tradition higher than God's word
What word would that be? The one that claims there were first people or a flood or 2M jews in goshen or an exodus or a great solomonic kingdom or a godman who was completely unique even though he was a carbon copy of numerous earlier godmen?

Because we know that none of those things ever happened. So that would put just about anything above 'gods word', wouldnt it?
because? "Because?" Huh?
-Because evidence says the god of abraham was either incompetent or a liar. This is despite whichever holy cult or coven or congregation you may wish to consult on the matter.
TheGhostofOtto1923
1 / 5 (1) Feb 02, 2014
It's those who realize this and love God, who don't reject his free gift of salvation
-But how can you believe that salvation nonsense if it comes from the same book as all those lies about first people and a flood and 2M jews in goshen and an exodus and a genocidal joshuan rampage and great davidic/solomonic kingdoms and a godman who was completely unique even though he was a carbon copy of numerous earlier godmen?

Since salvation is a promise from a god who is neither omnipotent nor omniscient nor even HONEST, what makes you think he would nevertheless grant all your wishes, give you immortality, and absolve you of your guilt for all those sins you transgressed? You know, the ones which are only sins because he SAYS they are?

Funny - your god makes you feel ashamed of yourself so he alone can make you feel better. We refer to this as a 'racket'. Its actually very similar to the way drugs addict you so only they can make you feel better.