In galaxy clustering, mass may not be the only thing that matters

January 25, 2016
Density maps of galaxy cluster distribution. Credit: Kavli IPMU

An international team of researchers, including Carnegie Mellon University's Rachel Mandelbaum, has shown that the relationship between galaxy clusters and their surrounding dark matter halo is more complex than previously thought. The researchers' findings, published in Physical Review Letters today, are the first to use observational data to show that, in addition to mass, a galaxy cluster's formation history plays a role in how it interacts with its environment.

There is a connection between galaxy clusters and their that holds a great deal of information about the universe's content of dark matter and accelerating expansion due to dark energy. Galaxy clusters are groupings of hundreds to thousands of bound together by gravity, and are the most massive structures found in the universe. These clusters are embedded in a halo of invisible dark matter. Traditionally, cosmologists have predicted and interpreted clustering by calculating just the masses of the clusters and their halos. However, theoretical studies and cosmological simulations suggested that mass is not the only element at play—something called assembly bias, which takes into account when and how a galaxy cluster formed, also could impact clustering.

"Simulations have shown us that assembly bias should be part of our picture," said Mandelbaum, a member of Carnegie Mellon's McWilliams Center for Cosmology. "Confirming this observationally is an important piece of understanding galaxy and formation and evolution."

A densely packed galaxy cluster. Credit: Kavli IPMU, adapted from Sloan Digital Sky Survey

In the current study, the research team, led by Hironao Miyatake, Surhud More and Masahiro Takada of the Kavli Institute for the Physics and Mathematics of the Universe, analyzed from the Sloan Digital Sky Survey's DR8 galaxy catalog. Using this data, they demonstrated that when and where galaxies group together within a cluster impacts the cluster's relationship with its environment.

The researchers divided close to 9,000 galaxy clusters into two groups based on the spatial distribution of the galaxies in each cluster. One group consisted of clusters with galaxies aggregated at the center and the other consisted of clusters in which the galaxies were more diffuse. They then used a technique called gravitational lensing to show that, while the two groups of clusters had the same mass, they interacted with their environment much differently. The group of clusters with diffuse galaxies were much more clumpy than the group of clusters that had their galaxies close to the center.

In galaxy clustering, mass may not be the only thing that matters
This comparison of galaxy clusters from the Sloan Digital Sky Survey DR8 galaxy catalog shows a spread-out cluster (left) and a more densely-packed cluster (right). A new study shows that these differences are related to the surrounding dark-matter environment. Credit: Sloan Digital Sky Survey

"Measuring the way galaxy clusters clump together on large scales is a linchpin of modern cosmology. We can go forward knowing that mass might not be the only factor in clustering," Mandelbaum said.

Explore further: Dark matter and galaxies part ways in collision between hefty galaxy clusters

More information: Evidence of Halo Assembly Bias in Massive Clusters, Physical Review Letters, dx.doi.org/10.1103/PhysRevLett.116.041301 , journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.041301 , On Arxiv: journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.041301

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36 comments

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Steelwolf
4.5 / 5 (4) Jan 25, 2016
Here is a question: Considering that we know that these huge galactic clusters are imbedded in massive clouds of their own, several million degree gas, with atomic densities being on the order of one atom per cubic meter, and thus this very hot gas is able to move for some distance, kilometers or more, before interacting with another atom, but, at millions of degrees, what is the actual, absolute speed of the individual atoms in this gas, and what, if any, Relatavistic effects this would have on surrounding space and each other?

Given that toroidal-type shape, one is reminded, again, of the articles:
http://phys.org/n...lky.html

And:
http://www.sci-ne...569.html

I like seeing how they come together, the different iterations of fractals on vastly different scales because there are too many similarities to discount.
shavera
4 / 5 (8) Jan 25, 2016
The individual particle speed really isn't all that important. The only "relativistic" effect that might be relevant for this discussion is the fact that the thermal energy of the gas will be an additional mass term in the cluster via E=mc^2. More specifically, from the rules of relativity you can directly define an associated mass that correlates with the temperature of any body through that relationship. eg, if you heat a disk of metal it will weigh just a tiny tiny bit more than when it was cold.
promile
Jan 25, 2016
This comment has been removed by a moderator.
Old_C_Code
3.2 / 5 (9) Jan 25, 2016
Simple answer; plasma physics is very complex. Dark matter? Ugh... ignore the conductive gas pervading the entire universe, dopes.
arom
Jan 25, 2016
This comment has been removed by a moderator.
Old_C_Code
2.6 / 5 (5) Jan 25, 2016
Due to the huge size of the halo of the sea of dark energy and dark matter in which the galaxy cluster immerged; understanding its nature may help the research ….


Understand it's called E&M, genius.
Gigel
3.6 / 5 (9) Jan 26, 2016
Simple answer; plasma physics is very complex. Dark matter? Ugh... ignore the conductive gas pervading the entire universe, dopes.

What is the electrical conductivity of the intergalactic gas? What is the voltage between 2 galaxies that ensures a significant current between them? What is the mechanism that maintains the voltage? And where is the Stark effect, if any, associated with the electric fields?
Whydening Gyre
5 / 5 (5) Jan 26, 2016
Simple answer; plasma physics is very complex. Dark matter? Ugh... ignore the conductive gas pervading the entire universe, dopes.

Would that be akin to the "man behind the curtain"?
Whydening Gyre
4.1 / 5 (9) Jan 26, 2016
What is the electrical conductivity of the intergalactic gas?

"Magnetic conductivity", then? Electric plasma charge perhaps being the carrier/magnifier of magnetic properties?
What is the voltage between 2 galaxies that ensures a significant current between them?

A simple magnetic "charge" differential, GENERATING an electric field would work. Voltage difference would be the "indicator" or possibly even, catalyst, of magnetic charge differential?
What is the mechanism that maintains the voltage?

Magnetic charge difference?
And where is the Stark effect, if any, associated with the electric fields?

Good question. Has this been checked for?
(to clarify, I used "charge" in the broader sense of strength and polarity)
Phys1
2 / 5 (8) Jan 26, 2016
"Magnetic conductivity", then? Electric plasma charge perhaps being the carrier/magnifier of magnetic properties?

What does that even mean?

A simple magnetic "charge" differential, GENERATING an electric field would work. Voltage difference would be the "indicator" or possibly even, catalyst, of magnetic charge differential?

What does that even "mean" ?
What is the mechanism that maintains the voltage?

Magnetic charge difference?

What does that even mean?
And where is the Stark effect, if any, associated with the electric fields?

Good question. Has this been checked for?

Of course.
(to clarify, I used "charge" in the broader sense of strength and polarity)

In physics "charge" means "charge". "strength" is not "charge". "polarity" means any of the things listed below
https://en.wikipe...Polarity
Man, what are you talking about ?
Phys1
2.1 / 5 (7) Jan 26, 2016
Due to the huge size of the halo of the sea of dark energy and dark matter in which the galaxy cluster immerged; understanding its nature may help the research ….


Understand it's called E&M, genius.

What is E&M? Some kind of department store? Genius ?
Colbourne
5 / 5 (1) Jan 26, 2016
Dark energy and dark matter can be replaced by repulsive particles surrounding galaxies etc.
This would help explain the early expansion of the universe and probably the apparent absence of anti-matter or other replulsive particles (which was initially pushing the normal matter apart and now is outside the galaxies possibly billions of light years away).
Gigel
3 / 5 (2) Jan 26, 2016
Dark energy and dark matter can be replaced by repulsive particles surrounding galaxies etc.
This would help explain the early expansion of the universe and probably the apparent absence of anti-matter or other replulsive particles (which was initially pushing the normal matter apart and now is outside the galaxies possibly billions of light years away).

That may actually work (still haven't found a critique to the antigravitational matter theory, but keep working on it). Yet wouldn't that mean that the Universe was in a lower energy state at the beginning? It got separated into repulsive mutually particles after that. Just a thought.
bluehigh
4 / 5 (4) Jan 26, 2016
* We can go forward knowing that mass might not be the only factor in clustering. *

Just to clarify, the intention of this statement is to allow the possibility that Mass via gravitational effects might be one factor or even only a minor influence.

So it's 'Assembly Bias'. A conveniently coined phrase that deflects attention from complete failure of mainstream astrophysics.

This kinda reeks of 'let's start covering our arse because the shits about to hit the fan'

When the revolution comes these frauds will be among those with their backs to the wall.

I want more strawberry cheesecake.

bschott
3.7 / 5 (6) Jan 26, 2016
What does that even mean?


X 3...followed by -

Man, what are you talking about ?

What is E&M? Some kind of department store? Genius ?


Go back to class, snuggle under your gravity equations and suck your thumb. Clearly from your confusion this too far above you.

Here is a simple explanation, the inter-stellar AND inter-galactic medium is 3 dimensional space and in this space are charged particles referred to as "plasma", as well as magnetic flux of varying intensities. This is very well documented.

To understand why things move the way they do in space, you must apply the physics which govern the motion of charged particles and objects with external magnetic fields.

One cannot do this with gravity and math without invoking DM and DE as "forces" which are contributing to the motion.

Since neither of those can be proven to exist and are ONLY evidenced by the motion of what we can see, the EVIDENCE points to EM fields as the prime driver of motion.

viko_mx
3.4 / 5 (5) Jan 26, 2016
In the universe there is no random events. Each movement of each cosmic object is programmed in advance. Also the physical laws, constants and fundamental forces.
Benni
4 / 5 (8) Jan 26, 2016
Since neither of those can be proven to exist and are ONLY evidenced by the motion of what we can see, the EVIDENCE points to EM fields as the prime driver of motion.


.........as would be evidence by the following equation for energy of a photon:

E=hv=hc/ λ

where E is energy,
h is Planck's constant per particle
λ is the wavelength of the photon

E=hv=hc/ λ = hc/0=infinity (an impossible condition)

It thus becomes obvious in accordance with this equation that as the frequency of the photon decreases there is a corresponding decrease in the energy content of the photon. Energy can never reach zero because hc/0 in the above equation becomes a meaningless quantity of infinity when a photon's wavelength is zero.

Applying some cockamamie theory of a gravity field so strong that such a field of gravity can slow down the velocity of a photon is nothing less than Funny Farm Science, yet black hole theorists think this is what happens at the surface of a BH.

Phys1
2.3 / 5 (9) Jan 26, 2016
Behold a collection of absolute cranks who share a phantasy, obsessive-compulsively copy pasting the same meaningless text over and over again.
It takes every kind of people!
Whydening Gyre
5 / 5 (7) Jan 26, 2016
"Magnetic conductivity", then?

What does that even mean?

A simple magnetic "charge" differential

What does that even "mean" ?
What is the mechanism that maintains the voltage?

Magnetic charge difference?

What does that even mean?
And where is the Stark effect, if any, associated with the electric fields?

Good question. Has this been checked for?

Of course.
(to clarify, I used "charge" in the broader sense of strength and polarity)

In physics "charge" means "charge". "strength" is not "charge". "polarity" means any of the things listed below
https://en.wikipe...Polarity
Man, what are you talking about ?

Man, I wish I knew...:-)
A field has an infinite number of orientations, polarity wise, primarily due to magnetic "charge" density variations (In turn due to interaction with OTHER fields in different orientations).
Whydening Gyre
4.4 / 5 (7) Jan 26, 2016
It thus becomes obvious in accordance with this equation that as the frequency of the photon decreases there is a corresponding decrease in the energy content of the photon. Energy can never reach zero because hc/0 in the above equation becomes a meaningless quantity of infinity when a photon's wavelength is zero.

What if... gravitational effect is actually causing the frequency to increase because of gravitationally bound acceleration?
Once again, dividing by 0 is a no-no. You can do it in an equation, maybe, but NOT reality. Because in reality, there IS no such thing.
Benni
3.3 / 5 (7) Jan 26, 2016
Behold a collection of absolute cranks who share a phantasy, obsessive-compulsively copy pasting the same meaningless text over and over again.
It takes every kind of people!


......coming from someone who has never gotten further than a 1st semester physics course, as your sign on handle implies, I can understand why you continue to have the same math & physics problem.
Benni
3.3 / 5 (7) Jan 26, 2016
It thus becomes obvious in accordance with this equation that as the frequency of the photon decreases there is a corresponding decrease in the energy content of the photon. Energy can never reach zero because hc/0 in the above equation becomes a meaningless quantity of infinity when a photon's wavelength is zero.


because of gravitationally bound acceleration?
There is no such thing as "gravitationally bound acceleration" on a photon. Where did you get the idea there is such a thing?

Once again, dividing by 0 is a no-no. You can do it in an equation, maybe, but NOT reality. Because in reality, there IS no such thing.
Yep, that's the point I keep making & is the point you keep missing because you erroneously imagine gravitationally bound photon acceleration exists somewhere in the universe, I guess at the surface of a black hole is where you imagine you can find it.
Benni
3 / 5 (6) Jan 26, 2016
E=hv=hc/ λ = hc/0=infinity (an impossible condition)


Once again, dividing by 0 is a no-no. You can do it in an equation, maybe, but NOT reality. Because in reality, there IS no such thing.


I see WG that you continue agreeing with the point I've been making time & again, that the condition of a photon at zero wavelength is an impossibility, because it results in E=infinity when the denominator (wavelength) is divided by zero, as I have again reiterated it above. But for some reason you still can't follow the simple math even though you seem to agree dividing by 0 is a no-no.

Do you have hidden away in your repertoire of artistic fetishes, an equation nobody knows about whereby gravity can create such a force on a photon by which such force can reduce a photon's velocity to zero? The 1st semester physics guy thinks one exists, but he has yet to produce it, E=hv=hc/ λ = hc/0=infinity proves such a force that can provide that much energy does not exist.

Phys1
2.5 / 5 (8) Jan 26, 2016
Benni the physics clown is at it again.
Benni does not know a photon from a turd.
Benni
2.5 / 5 (8) Jan 26, 2016
Benni the physics clown is at it again.
Benni does not know a photon from a turd.


So, Mr 1st semester physics genius: From where can infinite energy be derived such that setting the wave length of a photon to zero (hc/0) results in a calculation that makes any sense?

Come on, you want to be the smart guy here even though you never made to 2nd semester physics. So Mr smart guy, supply us with your "field equation" demonstrating your calculation for a force that results in reducing the velocity of a photon to zero, a condition that supposedly exists on the surface of black holes.
Whydening Gyre
4.3 / 5 (6) Jan 26, 2016

So, Mr 1st semester physics genius: From where can infinite energy be derived such that setting the wave length of a photon to zero (hc/0) results in a calculation that makes any sense?


I think you might be conflating wavelength with 3d velocity, not frequency.
Regardless, we know massive enough bodies will deflect photons (lensing). Then what's to stop an even more massive body from deflecting a photon into an "orbit"? (which, BTW, adds even MORE mass..). Get enough of them in "orbit" and what do have? An Event Horizon. Or possibly even a surface...
Benni
3 / 5 (6) Jan 26, 2016
From where can infinite energy be derived such that setting the wave length of a photon to zero (hc/0) results in a calculation that makes any sense?


I think you might be conflating wavelength with 3d velocity, not frequency.
So tell us how this works. The equation, E=hv=hc/ λ says what about about integration of "3d velocity"? Show me an equation in which velocity of a photon is frequency dependent.

Regardless, we know massive enough bodies will deflect photons (lensing). Then what's to stop an even more massive body from deflecting a photon into an "orbit"?
Soooo what, all photons travel only at one speed. How does placing it into an "orbit" slow it down? You got some math for this hidden beneath your paint brushes?

which adds even MORE mass. Get enough of them in "orbit" and what do have? An Event Horizon. Or possibly even a surface
Well now, here is a topic for conjecture.....an Event Horizon that occurs at the surface of a BH? Anybody?
Whydening Gyre
4.3 / 5 (6) Jan 26, 2016
So tell us how this works. The equation, E=hv=hc/ λ says what about about integration of "3d velocity"? Show me an equation in which velocity of a photon is frequency dependent.

E=mc/2
Frequency IS a measure of the wavelength, which you seem to be confusing it as the rate at which it is travelling (speed of light).

] Soooo what, all photons travel only at one speed. How does placing it into an "orbit" slow it down? You got some math for this hidden beneath your paint brushes?

It doesn't. It just packs more and more of them together into a (get this) - critical mass. And THAT slows it down.
I don't do paint (too messy), I do metal work.
Well now, here is a topic for conjecture.....an Event Horizon that occurs at the surface of a BH? Anybody?

I'm not even conjecturing. I'm extrapolatin'. The Event Horizon IS the surface.
And I personally feel "speed of light" inside a BH surface is c/2. Now THAT's conjecture...
Benni
3 / 5 (6) Jan 26, 2016
So tell us how this works.The equation, E=hv=hc/ λ says what about about integration of "3d velocity"? Show me an equation in which velocity of a photon is frequency dependent


E=mc/2
Frequency IS a measure of the wavelength, which you seem to be confusing it as the rate at which it is travelling (speed of light)
Can you even try to have a cogent thought? Show me where I made such a statement.

Soooo what, all photons travel only at one speed. How does placing it into an "orbit" slow it down? You got some math for this hidden beneath your paint brushes?


It doesn't. It just packs more and more of them together into a (get this) - critical mass. And THAT slows it down
To what speed does it slow it down? How slow do you imagine a photon can travel? Then what happens at your "critical mass" after they are moving so slowly, do they melt like ice cubes or what?

And I personally feel "speed of light" inside a BH surface is c/2.
Impressed Phys 1?
Whydening Gyre
5 / 5 (6) Jan 26, 2016
E=mc/2
Can you even try to have a cogent thought? Show me where I made such a statement.

Can't think when I'm wonderin' how those ski trails on your estate are doin'...
And - check your first "contribution" to the thread. You seem to intersperse wavelength and velocity with no differentiation.

To what speed does it slow it down?

No idea. Whatever the speed of Event Horizon spin?
How slow do you imagine a photon can travel?

Whatever speed the surround photons are travelling? Like a traffic jam.
Then what happens at your "critical mass" after they are moving so slowly, do they melt like ice cubes or what?

They gain mass?
And I personally feel "speed of light" inside a BH surface is c/2.

I restate - "speed of information exchange" is better than c, possibly c/2.
Benni
3 / 5 (6) Jan 27, 2016
And - check your first "contribution" to the thread. You seem to intersperse wavelength and velocity with no differentiation


.......you're confusing what you post with what I post.
Phys1
3.4 / 5 (5) Jan 27, 2016
No, he's not. Why else do you put lambda==0?
Why do copy/paste errors from yourself?
Benni
2.6 / 5 (5) Jan 29, 2016
No, he's not. Why else do you put lambda==0?


....Mr 1st Semester Physics guy, to make the point that it's an unidentifiable calculation, that λ set to 0.0 results in a quantity of INFINITE Energy. You see Mr 1st Semester Physics guy, you need to get to 2nd semester physics before you're able to come to some modicum of comprehension of material like this, but it appears you didn't make it because you failed the minimum standard pre-requisite in 1st semester physics, Physics 1.

You can't even come here & Copy & Paste an equation, so why would anyone expect you to know anything about any level in topics of physics.
viko_mx
1 / 5 (2) Jan 30, 2016
"In galaxy clustering, mass may not be the only thing that matters".

If so, why only in galaxy clustering? ;)

The definition of dark matter is magical virtual substance which hypothetical mass is added to the mass of observable matter in formulas of known metaphysical theories with the idea to make them more close to the observable physical reality. Otherwise this theories will look very inadequate to the reality.
viko_mx
1 / 5 (2) Jan 30, 2016
cnt
Phys1
4.2 / 5 (5) Jan 30, 2016
"In galaxy clustering, mass may not be the only thing that matters".

If so, why only in galaxy clustering? ;)

The definition of dark matter is magical virtual substance which hypothetical mass is added to the mass of observable matter in formulas of known metaphysical theories with the idea to make them more close to the observable physical reality. Otherwise this theories will look very inadequate to the reality.

But many, many orders of magnitude more adequate than yours.

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