Missing matter found by Monash student.

[scvblwxq]

Missing Dark Matter found by Monash student
http://www.monash.edu.au/news/show/monash-student-finds-universes-missing-mass
23 May 2011Dr Jasmina Lazendic-Galloway, Amelia Fraser-McKelvie and Dr Kevin Pimbblet
A Monash student has made a breakthrough in the field of astrophysics, discovering what has until now been described as the Universe’s ‘missing mass’. Amelia Fraser-McKelvie, working within a team at the Monash School of Physics, conducted a targeted X-ray search for the matter and within just three months found it – or at least some of it.

What makes the discovery all the more noteworthy is the fact that Ms Fraser-McKelvie is not a career researcher, or even studying at a postgraduate level. She is a 22-year-old undergraduate Aerospace Engineering/Science student who pinpointed the missing mass during a summer scholarship, working with two astrophysicists at the School of Physics, Dr Kevin Pimbblet and Dr Jasmina Lazendic-Galloway.

The School of Physics put out a call for students interested in a six-week paid astrophysics research internship during a recent vacation period, and chose Ms Fraser-McKelvie from a large number of applicants. Dr Pimbblet, lecturer in the School of Physics put the magnitude of the discovery in context by explaining that scientists had been hunting for the Universe’s missing mass for decades.

“It was thought from a theoretical viewpoint that there should be about double the amount of matter in the local Universe compared to what was observed. It was predicted that the majority of this missing mass should be located in large-scale cosmic structures called filaments - a bit like thick shoelaces,” said Dr Pimbblet.

Astrophysicists also predicted that the mass would be low in density, but high in temperature - approximately one million degrees Celsius. This meant that, in theory, the matter should have been observable at X-ray wavelengths. Amelia Fraser-McKelvie’s discovery has proved that prediction correct.

Ms Fraser-McKelvie said the ‘Eureka moment’ came when Dr Lazendic-Galloway closely examined the data they had collected.

“Using her expert knowledge in the X-ray astronomy field, Jasmina reanalysed our results to find that we had in fact detected the filaments in our data, where previously we believed we had not.”

X-ray observations provide important information about physical properties of large-scale structures, which can help astrophysicists better understand their true nature. Until now, they had been making deductions based only on numerical models, so the discovery is a huge step forward in determining what amount of mass is actually contained within filaments.

Still a year away from undertaking her Honours year (which she will complete under the supervision of Dr Pimbblet), Ms Fraser-McKelvie is being hailed as one of Australia’s most exciting young students. Her work has been published in one of the world’s oldest and most prestigious scientific journals, Monthly Notices of the Royal Astronomical Society.

“Being a published author is very exciting for me, and something I could never have achieved without the help of both Kevin and Jasmina. Their passion and commitment for this project ensured the great result and I am very thankful to them for all the help they have given me and time they have invested,” said Ms Fraser-McKelvie.

Dr Pimbblet said that he had under his tuition a very talented student who excelled in performing the breakthrough research.

“She has managed to get a refereed publication accepted by one of the highest ranking astronomy journals in the world as a result of her endeavours. I cannot underscore enough what a terrific achievement this is. We will use this research as a science driver for future telescopes that are being planned, such as the Australian Square Kilometre Array Pathfinder, which is being built in outback Western Australian.”

The paper can be found on the Cornell University website. http://arxiv.org/abs/1104.0711

 

[mrspeedybob]

So if dark matter (or at least some of it) emits x-rays then it must not be as exotic as previously thought. It must interact with electromagnetism which would mean there is a charge of some sort.

 

[matt.o]

This is not a detection of dark matter. This is a claimed detection of the missing baryons in the form of a warm-hot intergalactic medium which is though to contribute around half the mass of normal matter in the Universe.

 

[Chalnoth]

This is not a detection of dark matter. This is a claimed detection of the missing baryons in the form of a warm-hot intergalactic medium which is though to contribute around half the mass of normal matter in the Universe.

I should mention that it is even more conservative than that. It is a detection of some more normal matter in a few specific clusters. They don't go into the overall cosmological implications of this at all.

 

[matt.o]

I should mention that it is even more conservative than that. It is a detection of some more normal matter in a few specific clusters.

No, it's actually a claimed detection of X-ray emission from the filaments between clusters.

 

[Dotini]

They don't go into the overall cosmological implications of this at all.

No, it's actually a claimed detection of X-ray emission from the filaments between clusters.

After reading (or misreading?) the full text paper, it actually does suggest the rather alarming implication that clusters form at the intersection of filaments, rather than filaments collapsing into clusters. Please correct me if I'm misunderstanding this:

http://arxiv.org/PS_cache/arxiv/pdf/1104/1104.0711v2.pdf

Thanks,
Steve

 

[Chalnoth]

After reading (or misreading?) the full text paper, it actually does suggest the rather alarming implication that clusters form at the intersection of filaments, rather than filaments collapsing into clusters. Please correct me if I'm misunderstanding this:

http://arxiv.org/PS_cache/arxiv/pdf/1104/1104.0711v2.pdf

Thanks,
Steve

As I understand it, this is the general picture we obtain from numerical simulations. I don't see why it is that disturbing.

 

[matt.o]

After reading (or misreading?) the full text paper, it actually does suggest the rather alarming implication that clusters form at the intersection of filaments, rather than filaments collapsing into clusters. Please correct me if I'm misunderstanding this:

http://arxiv.org/PS_cache/arxiv/pdf/1104/1104.0711v2.pdf

Thanks,
Steve

Yes, clusters form at the intersection of filaments. The clusters gain mass as filaments "funnel" matter onto them.

 

[Dotini]

Yes, clusters form at the intersection of filaments. The clusters gain mass as filaments "funnel" matter onto them.

I was under the (perhaps false?) impression that matter was created from energy within Active Galactic Nuclei.

I'm an almost complete novice to cosmology, so please correct me if I'm off base.

Thanks greatly,
Steve

 

[twofish-quant]

Also you have to put it through the "journalism lens". "INEXPERIENCED NEWBIE MAKES WORLD SHAKING DISCOVERY" sounds cooler than "another day at the office in which you find something interesting"

 

[Dotini]

Yes, clusters form at the intersection of filaments. The clusters gain mass as filaments "funnel" matter onto them.

Okay, you're right, it's old news. I found this from 1979: "The phenomena of filamentation and chemical separation may be coupled, as in the presence of a temperature gradient, the plasma convection associated with filamentary structures provides an effective means of selective transport. The general principles of this mechanism are described here." http://www.nature.com/nature/journal/v277/n5695/abs/277370b0.html

Here, I found that "these filaments are the main birth sites of prestellar cores", and that they are all of a standardized width, no matter the length:
http://www.aanda.org/index.php?opti...oi&doi=10.1051/0004-6361/201116596&Itemid=129

The startling new thing to me is the notion that the web of filaments constitute the dominant (baryonic) structure of the universe, and that nebulae, stars and galaxies are somewhat secondary.

Please hasten to correct me if I'm making an unwarranted statement.

Thank you, and respectfully submitted,
Steve

 

[matt.o]

I was under the (perhaps false?) impression that matter was created from energy within Active Galactic Nuclei.

This sounds like the steady state model for the universe proposed by Narliker, Hoyle et al. which, based on overwhelming evidence in support of the competing Lambda Cold Dark Matter model (a variety of the big bang type models; see http://en.wikipedia.org/wiki/Lambda-CDM_model"[/URL]), has long been dimissed by mainstream cosmologists.

[quote="Dotini, post: 3325444"]Okay, you're right, it's old news. I found this from 1979: [I]"The phenomena of filamentation and chemical separation may be coupled, as in the presence of a temperature gradient, the plasma convection associated with filamentary structures provides an effective means of selective transport. The general principles of this mechanism are described here."[/I] [url]http://www.nature.com/nature/journal/v277/n5695/abs/277370b0.html[/url]
[/QUOTE]

Careful here, the filaments discussed in that paper refer to the specific phenomenon of filaments formed in plasmas. The filaments discussed in the press release from Monash refer to the filamentary structures connecting galaxy clusters, These filaments contain galaxies, dark matter and, as discussed in the press release, hot, X-ray emitting gas. The filaments stretch to sizes greater than 3 million parsecs, where one parsec is about 30 trillion kilometres.[quote="Dotini, post: 3325444"]Here, I found that [I]"these filaments are the main birth sites of prestellar cores"[/I], and that they are all of a standardized width, no matter the length:
[url]http://www.aanda.org/index.php?option=com_article&access=doi&doi=10.1051/0004-6361/201116596&Itemid=129[/url]
[/quote]

Again, careful here. This article is referring to filamentary structures [I]within[/I] a galaxy.

[quote="Dotini, post: 3325444"]The startling new thing to me is the notion that the web of filaments constitute the dominant (baryonic) structure of the universe, and that nebulae, stars and galaxies are somewhat secondary.
[/QUOTE]

Yes, but space is a big place! The filaments take up a much larger volume than stars and galaxies so while the gas is very tenuous, there is a lot of it!

 

[Dotini]

The startling new thing to me is the notion that the web of filaments constitute the dominant (baryonic) structure of the universe, and that nebulae, stars and galaxies are somewhat secondary.

Yes, but space is a big place! The filaments take up a much larger volume than stars and galaxies so while the gas is very tenuous, there is a lot of it!

Matt,
Thanks for your several helpful remarks. I'm recently retired from a dynamic group of Boeing scientists, engineers and techs, so I've joined several forums for continuing education and intellectual stimulation. I'm working my way through some of the wild ideas I've picked up along the decades but not had the time to explore. But I figure I'm not too terribly late because I sense that there's still problems, anomalies and controversies to solve, and that ever newer observations from NASA, ESA, the Japanese (and especially Australians!) will keep theorists hopping.

In view of the discovery that filaments precede and give birth to stars and galaxies, is it reasonable to assume that stars and galaxies would not exist at all without the filaments? Is it possible at this point to describe and put a timeline on the evolution of large scale cosmic filaments?

Thank you, and respectfully submitted,
Steve

 

[Sakha]

Is this paper trying to say that dark matter is actually baryonic mass?

 

[George Jones]

Is this paper trying to say that dark matter is actually baryonic mass?

No, this paper is about the specifics (what, where) of the universe's 4% normal matter component.

 

[Chalnoth]

Is this paper trying to say that dark matter is actually baryonic mass?

I think that was just very bad wording on the writers of the popular article that leads to that impression.

 

[Dotini]

Is this paper trying to say that dark matter is actually baryonic mass?

Maybe not directly. But now it looks like there's another that's edging ever closer to this awesome and portentous turning point - a true paradigm shift.

http://www.dailygalaxy.com/my_weblog/2011/06/radio-wave-emissions-near-milky-way-core-may-hold-the-ultimate-proof-of-dark-matter.html#more
http://blogs.physicstoday.org/newspicks/2011/06/dark-matter-may-explain-radio.html

The filaments --regions of high magnetic fields that emit radio waves of high frequency--have been a mystery to astronomers since they were first discovered in the 1980s. The region within 900 light-years of the Milky Way Galaxy's core is crisscrossed with glowing filaments 1 to 3 light-years thick and 10 to 100 light-years long. They are a recent discovery, known only since the invention of modern radio and infrared telescopes that can "see" through the visually opaque dust clouds shrouding the galaxy core. The latest radio telescope probes of this region show that the filaments are associated with pockets of star-formation.

"There's a long literature about these objects, and there have been some ideas as to what might generate their emission - but frankly no one really knows," said Dan Hooper, an astrophysicist at the Fermi National Accelerator Laboratory (Fermilab) in the US and co-author of the paper, which is under review by academics.

One explanation for this emission would be what is called synchrotron radiation, which arises when charged particles are accelerated in a magnetic field. There are several ideas that could account for the emission which do not invoke dark matter - so called "astrophysical" mechanisms.

Respectfully submitted,
Steve

 

[Chalnoth]

Maybe not directly. But now it looks like there's another that's edging ever closer to this awesome and portentous turning point - a true paradigm shift.

http://www.dailygalaxy.com/my_weblog/2011/06/radio-wave-emissions-near-milky-way-core-may-hold-the-ultimate-proof-of-dark-matter.html#more
http://blogs.physicstoday.org/newspicks/2011/06/dark-matter-may-explain-radio.html

The filaments --regions of high magnetic fields that emit radio waves of high frequency--have been a mystery to astronomers since they were first discovered in the 1980s. The region within 900 light-years of the Milky Way Galaxy's core is crisscrossed with glowing filaments 1 to 3 light-years thick and 10 to 100 light-years long. They are a recent discovery, known only since the invention of modern radio and infrared telescopes that can "see" through the visually opaque dust clouds shrouding the galaxy core. The latest radio telescope probes of this region show that the filaments are associated with pockets of star-formation.

"There's a long literature about these objects, and there have been some ideas as to what might generate their emission - but frankly no one really knows," said Dan Hooper, an astrophysicist at the Fermi National Accelerator Laboratory (Fermilab) in the US and co-author of the paper, which is under review by academics.

One explanation for this emission would be what is called synchrotron radiation, which arises when charged particles are accelerated in a magnetic field. There are several ideas that could account for the emission which do not invoke dark matter - so called "astrophysical" mechanisms.

Respectfully submitted,
Steve

I have a really hard time believing that the quantity of matter that arises as a result of dark matter annihilations can possibly compete with the normal ionized matter in the galaxy currently. Maybe, but it's going to be difficult to demonstrate.

And by the way, these reports are about an attempt to explain filaments using dark matter, not the other way around.

 

[Dotini]

And by the way, these reports are about an attempt to explain filaments using dark matter, not the other way around.

Of course. EVERYTHING must be done to defend the paradigm before conceding its failure. What we are seeing is the thin end of the wedge. We live in exciting times made possible by radio astronomy - and its a blessing to have tools to see the way out of the darkness of ignorance.

Yours,
Steve

 

[Chalnoth]

Of course. EVERYTHING must be done to defend the paradigm before conceding its failure. What we are seeing is the thin end of the wedge. We live in exciting times made possible by radio astronomy - and its a blessing to have tools to see the way out of the darkness of ignorance.

Wow. Now you've just gone off the deep end. It is the evidence which has driven the astronomy/cosmology community to believe in the existence of dark matter. The ones who are clinging to dogma are the ones who continue to deny this copious and varied evidence in favor of dark matter.

In the end, this particular work in no way, shape, or form deserves your rather visceral and asinine response. It is a bit of quite valid theoretical work (even if I strongly suspect it's wrong in the end).