# I Action Dynamics of the Local Supercluster

#### |Glitch|

Interactive visualization of the fully nonlinear gravitationally induced trajectories of a nearly complete set of galaxies, groups, and clusters in the Local Supercluster constructed in a Numerical Action Method (NAM) model constrained by data from the CosmicFlows survey and various distance indicators. The Virgo, Fornax, Antlia and Virgo W clusters are represented by large spheres colored red, khaki, black, and purple, respectively. The Milky Way and M31 galaxies are shown by smaller spheres colored yellow and green, respectively. Others are colored blue. The time evolution runs from the past 13.25 billion years to present.
The interactive model can be found at: Action Dynamics of the Local Supercluster Interactive Model

Source:
Action Dynamics of the Local Supercluster - The Astrophysical Journal, Volume 850, Number 2, December 2017 (free preprint)

Related Astronomy and Astrophysics News on Phys.org

#### Arman777

Gold Member
Its very interesting..I am not sure but are all of the galaxies approaching to clusters for example to the Virgo ?
I search something and find this

"What I think is the most amazing fact about the supercluster, is that in 100 billion years from now, the gravitational attraction between galaxies and clusters will have pulled it all into a single, enormous, writhing mass of stars. At this time, other superclusters will also be converging together, separated by billions of light years due to the expansion of the Universe. However, something interesting that you may be familiar with is that astronomers have actually noticed an unusual movement of galaxy clusters within the supercluster. Many are moving in the direction of the Norma Cluster, but it is very difficult to see why because of the large amount of material in the Milky Way’s plane. For now this has been dubbed the ‘Great Attractor’ due to its unexplained tug. It may, in fact, be related to dark flow: a mysterious force tugging on galaxy clusters from beyond the scope of the observable universe."
(https://www.quora.com/What-is-a-virgo-supercluster)

So my question makes sense or in general it makes sense and its amazing. Can we see Norma cluster in this interactive model, or its affects?

Gold Member

#### Arman777

Gold Member
"dark flow" seems to be a very problematic theory: https://en.wikipedia.org/wiki/Dark_flow
The idea is really interesting. But I didnt quite get it. Isn't it normal that galaxies move towards clusters ? Galaxies can have peculiar velocities and can be attracted to clusters due to gravity.

In description of dark flow it says ""non random" ? peculiar velocity is a random motion yes but its caused by gravity right so what is this extra motion ?

or am I missing something ?

#### phinds

Gold Member
The idea is really interesting. But I didnt quite get it. Isn't it normal that galaxies move towards clusters ? Galaxies can have peculiar velocities and can be attracted to clusters due to gravity.

In description of dark flow it says ""non random" ? peculiar velocity is a random motion yes but its caused by gravity right so what is this extra motion ?

or am I missing something ?
You have the first part right. "Dark Flow" is a supposed anomaly in that it has a preferred direction. Did you not read the Wikipedia article?

#### Arman777

Gold Member
You have the first part right. "Dark Flow" is a supposed anomaly in that it has a preferred direction. Did you not read the Wikipedia article?
Oh wait I see now,
$v_r=H_0d+v_{pec}$ and in here
$v_{pec}$ has some non random component but $v_{pec}$ is actually random motion, so this is a anomaly

#### |Glitch|

Its very interesting..I am not sure but are all of the galaxies approaching to clusters for example to the Virgo ?
I search something and find this

"What I think is the most amazing fact about the supercluster, is that in 100 billion years from now, the gravitational attraction between galaxies and clusters will have pulled it all into a single, enormous, writhing mass of stars. At this time, other superclusters will also be converging together, separated by billions of light years due to the expansion of the Universe. However, something interesting that you may be familiar with is that astronomers have actually noticed an unusual movement of galaxy clusters within the supercluster. Many are moving in the direction of the Norma Cluster, but it is very difficult to see why because of the large amount of material in the Milky Way’s plane. For now this has been dubbed the ‘Great Attractor’ due to its unexplained tug. It may, in fact, be related to dark flow: a mysterious force tugging on galaxy clusters from beyond the scope of the observable universe."
(https://www.quora.com/What-is-a-virgo-supercluster)

So my question makes sense or in general it makes sense and its amazing. Can we see Norma cluster in this interactive model, or its affects?
According to their paper, the model does include the affects of the "Great Attractor."
In addition, the alignment of major masses, from the Shapley Concentration (Raychaudhury 1989; Scaramella et al. 1989) through the Norma−Centaurus−Hydra complex (Great Attractor) (Lynden-Bell et al. 1988), to the Perseus−Pisces filament (Haynes & Giovanelli 1988) creates a strong tidal field at our location (Lilje et al. 1986; Dekel et al. 1999; Romano-D ́ıaz et al. 2005).

#### Arman777

Gold Member
According to their paper, the model does include the affects of the "Great Attractor."
Thats nice..Its hard to see in the model I guess..I wish they could give it a color.

"Action Dynamics of the Local Supercluster"

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving