Gaseous halos of galaxies are much larger, more massive than the distribution of stars within the galaxy

Nov 17, 2011
The illustration shows how quasistellar object (QSO) absorption lines are used to study the vast (and effectively invisible) gaseous halos of galaxies. When the light from a distant QSO passes through the gas surrounding a foreground galaxy (schematically indicated with a red dashed circle), some of the colors of the QSO light are absorbed by the foreground material. Consequently, the Hubble Space Telescope observes that some of the colors are “missing.” By studying the absorbed colors, astronomers can determine many things about the gaseous halo, such as composition, temperature, density and mass. This technique has revealed that the gaseous halos of galaxies as much larger and more massive than the distribution of stars within the galaxy. These large halos are produced by “winds” of matter rapidly moving away from the galaxies. Courtesy of Todd M. Tripp, UMass Amherst and NASA Galaxy Evolution Explorer

New, high-precision equipment orbiting Earth aboard the Hubble Space Telescope is now sending such rich data back to astronomers, some feel they are crossing the final frontier toward understanding galaxy evolution, says Todd Tripp, leader of the team at the University of Massachusetts Amherst.

Galaxies are the birthplaces of stars, each with a dense, visible central core and a huge envelope, or halo, around it containing extremely low-density gases. Until now, most of the mass in the envelope, as much as 90 percent of all mass in a galaxy, was undetectable by any instrument on Earth.

But Hubble's sensitive new Spectrograph (COS), the only one of its kind, has dramatically improved the quality of information regarding the of galaxies, Tripp says. This huge gain in precision is one of the enormous accomplishments of the COS mission. "Even 10 years ago, most of the mass of a galaxy was invisible to us and such detailed investigations were impossible." the UMass Amherst astronomer points out. "With COS, in a sense we now have the ability to see the rest of the iceberg, not just the tip. This is a very exciting time to be an astronomer."

Tripp, postdoctoral researcher Joe Meiring and theoretical astronomer Neil Katz are co-authors of several companion articles reporting advances in understanding galaxy evolution based on the new COS data in the Nov. 18 issue of Science. Other lead investigators are Nicolas Lehner of the University of Notre Dame and Jason Tumlinson of the Space Telescope Science Institute, Baltimore.

"With the new spectrograph we can see galaxy halos out to at least 150,000 parsecs," says Tripp. One kiloparsec is about 19 trillion miles. "Where once we saw only the framework we are now getting a more complete picture, including the composition and movement of gases in the envelope, varying temperatures in different locations and the , all in incredible detail," Tripp adds.

In particular, data on the chemical composition and temperature in the gas clouds allow the astronomers to calculate a galaxy's halo mass and how the gaseous envelope regulates the galaxy's evolution.

Another overall mission focus is to explore how galaxies gather mass for making stars. The astronomers have found that heavy elements in the envelopes surrounding the most vigorous star-forming galaxies continuously recycle material, as supernovae explode and shoot hot gas for trillions of miles. Faster-moving material escapes the envelope, but slower- moving particles collapse back into the center and restart the cycle.

Tripp and his UMass Amherst team specialize in studying how the fast-moving gases and matter from exploding supernovae circulate in galaxies. It was a surprise to discover how much mass extends far outside each galaxy, he says. "Not only have we found that star-forming galaxies are pervasively surrounded by large halos of hot gas," says Tripp, "we have also observed that hot gas in transit. We have caught the stuff in the process of moving out of a galaxy and into intergalactic space."

Further, the speed at which gases are moving in different parts of a galaxy is critical. Slower speeds may mean cooling gases, ready to collapse back into the core. Hotter gases are likely expanding and might escape the envelope.

Because the light emitted by this hot plasma is so faint that it is effectively invisible, astronomers use a trick to illuminate it from behind, like studying a misty fog bank by looking through lighthouse beams. In this case the lighthouse is usually a quasar, a super bright object behind the galaxy of interest. Gathering several sightings through the fog, scientists can piece together a map of the gaseous envelope.

Certain wavelengths of light emitted by the quasar are absorbed by the ions in a galaxy's envelope. With COS, a whole new area of the electromagnetic spectrum has become visible. To learn more, Tripp and colleagues also calculate concentrations of the many elements such as hydrogen, oxygen, sulfur, carbon and neon in the envelope, plus up to five ions of each. One of the neon ions has turned out to be particularly important.

"In detecting the neon ions we find that there's a lot of gas at several hundred thousand degrees Kelvin, which we've never been able to see unambiguously before," says Tripp. "It means we can characterize the total mass distribution in the envelope, setting more precise constraints on the temperatures overall. We can now access more diverse ions, and we have new leverage on determining whether stuff is heating up or cooling off. We're gaining new insights."

The neon ion will also play a role in testing theoretical models of . Theorists including Katz at UMass Amherst construct model on a computer, simulating its make-up and how it evolves over time. Tripp says, "Now we have hard data to plug into the model and test their ideas. They've got a lot of detailed predictions we can now compare to the real universe. It's a new day for all of us."

Explore further: How baryon acoustic oscillation reveals the expansion of the universe

Provided by University of Massachusetts at Amherst

4.8 /5 (9 votes)

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tadchem
2 / 5 (4) Nov 17, 2011
It sounds like a significant mass of 'dark matter' can be accounted for by this.
Nik_2213
2.3 / 5 (3) Nov 17, 2011
If they've found the 90% missing matter, does this exclude 'Dark Matter' ??
that_guy
3.7 / 5 (6) Nov 17, 2011
Unfortunately, I'm not sure how much gas was already assumed to be out there, but yeah, it does seem like this will be a piece in that puzzle.

I don't mean to denigrate those who believe in the current standard model and DM, but there are a lot of us waiting for new science/observations to get some of this crap overturned.
omatumr
1 / 5 (16) Nov 17, 2011
Galaxies are the birthplaces of stars, each with a dense, visible central core and a huge envelope, or halo, around it containing extremely low-density gases.


If the gaseous envelope consists of waste products (mostly H and He) from the central core (mostly neutrons), then the mass of the envelope will increase as the mass of the central core decreases [1-5].

1. "Attraction and repulsion of nucleons: Sources of stellar energy," JFE 19, 93-98 (2001)
www.omatumr.com/a...tnuc.pdf

2. "Neutron repulsion confirmed as energy source," JFE 20, 197-201 (2002)
www.springerlink....6685079/

3. "The Sun is a plasma diffuser that sorts atoms by mass," PAN 69, 1847-1856 (2006)
http://arxiv.org/.../0609509

4. "Is the Universe Expanding?" J. Cosmology 13, 4187-4190 (2011)
http://journalofc...102.html

5. "Neutron Repulsion", APEIRON J., in press (2011)
http://arxiv.org/...2.1499v1

With kind regards,
Oliver K. Manuel
Parsec
4 / 5 (6) Nov 17, 2011
It sounds like a significant mass of 'dark matter' can be accounted for by this.

Dark matter is non-hadronic. In other words, it cannot be made up of ordinary matter. There is a rather significant amount of ordinary matter astronomers cannot account for. Since this is ordinary matter, I suspect that these observations will go a long way to accounting for it.
Parsec
4 / 5 (6) Nov 17, 2011
Unfortunately, I'm not sure how much gas was already assumed to be out there, but yeah, it does seem like this will be a piece in that puzzle.

I don't mean to denigrate those who believe in the current standard model and DM, but there are a lot of us waiting for new science/observations to get some of this crap overturned.

DM isn't part of the standard model. The standard model refers to the composition of particles of ordinary matter. The properties of DM require a particle (or particles) not described by the SM. The evidence for DM is quite strong by the way, and continues to get stronger. That is the only reason people believe in that 'crap'.
that_guy
2.4 / 5 (5) Nov 17, 2011
DM isn't part of the standard model. The standard model refers to the composition of particles of ordinary matter. The properties of DM require a particle (or particles) not described by the SM. The evidence for DM is quite strong by the way, and continues to get stronger. That is the only reason people believe in that 'crap'.

Pardon me for being unclear. I meant the standard cosmological model, using the phrase descriptively, rather than Standard Model, a proper noun.

There is plenty of evidence that there is more going on than we think - IE the invention of 'Dark Matter' - but the evidence in no way could be considered quite strong and getting stronger. The evidence could be described as 'perplexing' and 'inconclusive' and even 'suggestively supporting DM', But definitely not quite strong. There are a few strong observations that do support DM, but they do not rule out alternatives, and some of the best 'evidence' for DM is frustratingly inconsistent.

jsdarkdestruction
4.1 / 5 (9) Nov 17, 2011
Oliver Manuel's recent efforts to plaster Physorg.com and other public news sites with his theories and personal URLs are a bit puzzling, as scientists have a variety of publications available to communicate directly to each other in. My best guess is that he is desperately trying to prop up his legacy in light of his arrest in his university office on 7 charges of rape and sodomy based on allegations by 4 of his own children. The charges have been reduced to one count of felony attempted sodomy, not necessarily because of his innocence, but because of the statute of limitations. One can only guess how the recent charges and decades of family strife have affected his ability to reason rationally and to remain objective while defending his unpopular theories.

http://www.homefa...uel.html

http://mominer.ms...hildren/
Callippo
1 / 5 (5) Nov 17, 2011
Gaseous halos of galaxies are much larger, more massive than the distribution of stars within the galaxy
Plasma universe at its best. IMO most of these halos are formed with antimatter.
Deesky
5 / 5 (3) Nov 17, 2011
If they've found the 90% missing matter, does this exclude 'Dark Matter' ??

That's a little misleading. It's not the case that the mass was 'missing', but more that it was invisible to prior detection techniques. This mass comprises normal, but hard to detect baryonic mass - basically hot gasses, and is not at all related to dark matter.

However, what would be interesting is to plot the map of the newly detected halo gasses to the DM halo distribution.
Deesky
4.2 / 5 (5) Nov 17, 2011
There is plenty of evidence that there is more going on than we think - IE the invention of 'Dark Matter' - but the evidence in no way could be considered quite strong and getting stronger.

And you'd be quite wrong. DM wasn't 'invented' on a whim, it is required to explain observations and how our universe developed, from BB to now.

The evidence could be described as 'perplexing' and 'inconclusive' and even 'suggestively supporting DM', But definitely not quite strong

No, it's very strong indeed. The evidence comes from at least half a dozen independent sources.

There are a few strong observations that do support DM, but they do not rule out alternatives

They pretty much do. The only candidate is MOND, but that is a PURELY ad hock fudge, works only in some cases and has serious issues with relativity. It is not considered seriously in the cosmology community.
Cynical1
not rated yet Nov 18, 2011
On gravity - is it an additive kind of force? I mean, if you measure the mass n gravity of several bodies individually and add them to each other, is the amount of gravitational force the same as single body with the same amount of mass? Or is the gravitational force stronger for the combined mass body?
joefarah
1 / 5 (1) Nov 18, 2011
There is a lot of debate here about DM theory. Suffice it to say that such theory is that - needed to support observations within a defined model. This is a change in observations, although the article does apply to "Star-forming galaxies" - I'd like to know what percentage of galaxies this actually refers to in terms of the numbers (90%) presented.

As well, there are a number of other credible theories that eliminate the need for DM, some more promising than others. Unfortunately, we are not likely to nail down theories and observations sufficiently any time soon to prove or disprove the existence of DM.

Nonetheless, I'll give credibility to DM theory until the James Watt observatory is launched and has had a chance to peer through the heavens for a bit (or DM is otherwise put to rest). After that, I'll put DM into a wrong model category.
that_guy
1 / 5 (1) Nov 18, 2011
And you'd be quite wrong. DM wasn't 'invented' on a whim, it is required to explain observations and how our universe developed, from BB to now.

No, it's very strong indeed. The evidence comes from at least half a dozen independent sources.

There are a few strong observations that do support DM, but they do not rule out alternatives

They pretty much do. The only candidate is MOND, but that is a PURELY ad hock fudge, works only in some cases and has serious issues with relativity. It is not considered seriously in the cosmology community.


DM is a phrase coined to support that essentially our gravity measurements don't line up with the estimated mass of galaxies. There is plenty of good evidence for that anamoly, but it is largely a lot of observations about a single aspect.

The only other real DM evidence comes from trying to directly detect DM particles. The results vary from experiment to experiment and sometimes conflict.

Cont...
that_guy
1 / 5 (1) Nov 18, 2011
Yes, if you research dark matter, it was named on a whim. It appeared that some unseeable matter was causing excess gravity - Ergo, Dark Matter. Simple as that. History.

I am not in a position to say that DM is definitely wrong - that would be presumptuous. But you saying that it is definitely right is just as presumptuous.

As for MOND, I'm a little doubtful of that too. I'm pretty sure that even if parts of it are right, that it is missing some key factors. There are certainly a number of other valid theories that gain less press as well.

My point here is that before newton, there were no correct ideas about gravity/motion out there. Some were close. Before Einstein, no one had suggested relativity so eloquently and accurately as him. I'm fairly certain, from history, that we may have something that resembles the truth in some way, but we are most likely a good bit off as of yet.
Deesky
5 / 5 (1) Nov 18, 2011
DM is a phrase coined to support that essentially our gravity measurements don't line up with the estimated mass of galaxies

Yes, but that is a HUGE problem, as GR is one of our most successful theories of reality and one of the corner stones of our understanding of the universe. And it's not just limited to galaxies.

There is plenty of good evidence for that anamoly, but it is largely a lot of observations about single aspect

You are wrong there. Modelling the evolution of the universe without DM would result in a universe that looked nothing at all like it does. DM is REQUIRED for the universe to look like it does today. WMAP's CMB data also supports the existence of L-CDM. So that 'single aspect' has MULTIPLE observational support.

The only other real DM evidence comes from trying to directly detect DM particles

Not in the least. In fact, such a detection has not yet proved fruitful, so it's the opposite of what you assert. See above for real supporting evdnce
Deesky
5 / 5 (1) Nov 18, 2011
if you research dark matter, it was named on a whim. It appeared that some unseeable matter was causing excess gravity

And you entirely miss the point. My use of the term 'whim' was in relation to inventing a theory for no good reason, and not HOW it was named!

I am not in a position to say that DM is definitely wrong - that would be presumptuous. But you saying that it is definitely right is just as presumptuous

You're being presumptuous. All I have said is that the evidence for DM is solid - I never said it was DEFINITELY true. That would be a foolish position.

I'm fairly certain, from history, that we may have something that resembles the truth in some way, but we are most likely a good bit off as of yet

Science is a process where new knowledge supplants the old. We will never know whether our theories are a 'true' description of reality. However, along that journey certain things acquire legitimacy as more and more evidence comes in from multiple sources.
that_guy
not rated yet Nov 18, 2011
That single aspect has plenty of observational support, yes. But it is still a single aspect - observationally, it seems that there is more gravity than scientists are estimating should happen. All the extra observations do is confirm in fact yes, you can observe this same phenomenon in different ways.

Under CERTAIN simulations, DM seems to be a good fit to make our 'modeled' universe work correctly. However, they are-
1. adjusting the parameters to make it fit - not that i disagree with that, as it helps them figure out how to observe DM by giving clues as to its nature.
2. There are multiple competing models of DM that can be put in those simulations and work. Some have been ruled out because they can't be found IRL.
3. Presumably they are modeling a semblance of a real effect. it could easily be wrong, but have close enough numbers to seem right.
4. These models are very preliminary. There could be many other wrong or innacurate factors throwing it completely off.
that_guy
1 / 5 (1) Nov 18, 2011
The most damning part about DM is that most experiments to directly detect it show nothing where you should see it.

And one or two that do show supposed signals directly conflict with other, higher resolution experiments. This is the conflicting evidence I'm talking about.

Now I know that we will always have different camps and all, and it's fine to have different opinions. But in my opinion, I personally believe that DM theory will be the thread that will pull us all the way back to the big bang and adjust everything in between.

I'm waiting for an einstein moment - Either somebody pins the DM mechanism down in an elegant way that sews everything together (Which I doubt) or an eventual abandonment of DM, following the crumb trail, until someone comes up with the piece of the puzzle that completes the picture.
PinkElephant
not rated yet Nov 18, 2011
From the article:
One kiloparsec is about 19 trillion miles.
For American readers: that EU-style "trillion" is actually what we here call quadrillion, i.e. 10 to the power of 15. (In Europe, they call our billion a 'milliard', our trillion a 'billion', and so on from there.)
Deesky
5 / 5 (1) Nov 18, 2011
The most damning part about DM is that most experiments to directly detect it show nothing where you should see it.

How can you directly detect something which doesn't interact with ordinary baryonic matter except through gravity? In fact, the most direct detections have been due to gravitational lensing. Many such lensing events have been made and whole sky-maps have been plotted.

And then there's the Bullet cluster, where the spatial offset of the center of the total mass from the center of the baryonic mass peaks CANNOT be explained with an alteration of the gravitational force law.

As for direct detection, IMO the best chance would come from the LHC experiments dealing with SUSY.
Deesky
5 / 5 (1) Nov 18, 2011
And one or two that do show supposed signals directly conflict with other, higher resolution experiments. This is the conflicting evidence I'm talking about.

Sure, the details vary, but that is to be expected when dealing with an elusive phenomenon.

Everyone talks of the big bang theory as if it's a single theory, when in fact there are hundreds of variants with different attributes, but the evidence for the overarching BB theory is overwhelming, nonetheless.
Cynical1
not rated yet Nov 19, 2011
No one has yet answered my question. Is gravity additive or geometric? I mean is the whole greater than the added sum of the parts?
Tuxford
1 / 5 (3) Nov 19, 2011
It was a surprise to discover how much mass extends far outside each galaxy, he says.

We have caught the stuff in the process of moving out of a galaxy and into intergalactic space.

In LaViolette's superwave phenomenon, core ejections are cyclic, expelling matter throughout the galaxy. Furthermore, in this model, matter is continuously created, even in empty space, and somewhat more rapidly in regions of higher mass density, such as surrounding galaxies. The enhanced matter-creation potential of this region may also reveal itself as dark matter characteristics.
FrankHerbert
0.7 / 5 (48) Nov 19, 2011
@that_guy

But you saying that it is definitely right is just as presumptuous.


Who said that exactly? What it sounds like to me is you actually think DM is "definitely wrong" (but aren't willing to say that exactly, just everything you say happens to go along with that sentiment), yet in order to feel some form of credibility you have to ascribe your shortcomings to others. I haven't heard anyone here say DM is definitely true (as there is no accepted model of it). If you actually care to ask you may inquire which model is each posters favorite. And just because someone has a pet theory doesn't mean that person believes it is an indisputable model of reality.
eachus
5 / 5 (2) Nov 19, 2011
Nonetheless, I'll give credibility to DM theory until the James Watt observatory is launched and has had a chance to peer through the heavens for a bit (or DM is otherwise put to rest). After that, I'll put DM into a wrong model category.


Is that the telescope that will look for intergalactic steam?

(Sorry, couldn't resist. The JWST is the James Webb Space Telescope, named after a former head of NASA. James Watt is the inventor of the steam engine. ;-)
Cynical1
1 / 5 (1) Nov 19, 2011
Is that the telescope that will look for intergalactic steam?

(Sorry, couldn't resist. The JWST is the James Webb Space Telescope, named after a former head of NASA. James Watt is the inventor of the steam engine. ;-)

Very good eye, Eachus...:-)

The funny thing is, it may end up being that simple...:-)
mosahlah
3.5 / 5 (2) Nov 20, 2011
Is it just me, or do we know less about the universe than we did a year ago?
Ober
not rated yet Nov 20, 2011
No one has yet answered my question. Is gravity additive or geometric? I mean is the whole greater than the added sum of the parts?

Gravity is proportional to mass and the effective gravity is mass per volume ie density. Hence a star with a fixed mass becomes a black hole by increasing its density (ie reducing its volume while maintaining its mass). So yest it is additive, AND geometric.