Graph of rotation curve of a cluster (not a galaxy)

In summary: This radiation pressure drives the gas out of the galaxy, and the more gas there is, the more pressure there is to expel it.In summary, galaxy clusters have a variety of shapes, some more regular than others, and their rotation curves are difficult to measure.
  • #1
Buckethead
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I'm familiar with galactic rotational curves and there are plenty of graphs depicting such curves, but I'm interested in the rotation curves of entire galactic clusters at the moment and I'm not too good with sifting through what shows up in the search engines. (not a physicist, just a hobbyist) Has anyone graphed the rotation curve of any cluster? What I'm interested in learning is:
1) the locations of the galaxies involved relative to the axis of rotation of the cluster (not all, just a handful but at varying distances from the axis)
2) the velocities of these galaxies around the axis of rotation.
3) (optional) The single dimension location of the galaxy along the axis
3) these things depicted in a graph or in the absence of that, the spreadsheet or chart.

I would think this would be out there somewhere, but I'm at a loss how to find it, but perhaps someone here is actually doing work on this sort of thing.

Thanks,
 
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One issue is that galaxy clusters don't have a single axis of rotation. Each galaxy in the cluster may be orbiting in a different plane entirely from every other.

Instead, what is measured for galaxy clusters is the velocity dispersion, as you can see here for example:
https://ned.ipac.caltech.edu/level5/Biviano/Biviano6_3.html
 
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Thank you for the reply and insight. Does this mean that clusters are more like elliptical galaxies than spiral galaxies if an analogy were to be drawn? In this case one more thing I would need to know is the plane of rotation and the direction (clockwise or counter clockwise within this plane) for the study I'm trying to do. Is this data just not available in this form?
 
  • #4
Buckethead said:
Thank you for the reply and insight. Does this mean that clusters are more like elliptical galaxies than spiral galaxies if an analogy were to be drawn? In this case one more thing I would need to know is the plane of rotation and the direction (clockwise or counter clockwise within this plane) for the study I'm trying to do. Is this data just not available in this form?
Yes, clusters are more like elliptical galaxies. However, being larger and with fewer constituents* than galaxies, they tend to have less regular shapes.

As for whether the data exists, I don't really know. I suspect that some data on this exists, but it may be difficult to track it down precisely.

* Fewer in the sense that the number of galaxies in a cluster is much, much less than the number of stars in a galaxy.
 
  • #5
FWIW, clusters have very high proportions of dark matter, while elliptical galaxies have low proportions of dark matter (and the amount of dark matter in an elliptical galaxy is strongly correlated with the extent to which is is not spherical - nearly spherical elliptical galaxies have the least dark matter of any galaxy type).
 
  • #6
ohwilleke said:
FWIW, clusters have very high proportions of dark matter, while elliptical galaxies have low proportions of dark matter (and the amount of dark matter in an elliptical galaxy is strongly correlated with the extent to which is is not spherical - nearly spherical elliptical galaxies have the least dark matter of any galaxy type).
I doubt that has much impact. My understanding is that the prevailing model has the amount of gas and dust in the galaxy being the primary determinant of its fate. Spiral galaxies tend to have a lot more gas and dust, and it is likely that the friction of this material is what causes them to settle into this shape.

From what I recall, the primary way that gas becomes expelled from a galaxy is by radiation pressure from an active galactic nucleus.
 

Related to Graph of rotation curve of a cluster (not a galaxy)

What is a rotation curve of a cluster?

A rotation curve of a cluster is a graph that shows the distribution of matter within a cluster of galaxies, based on the rotational velocities of the galaxies in that cluster. It is typically plotted as a function of distance from the center of the cluster.

How is the rotation curve of a cluster different from that of a galaxy?

The rotation curve of a cluster is different from that of a galaxy because it takes into account the combined gravitational effects of all the galaxies within the cluster, rather than just the rotation of individual galaxies. This can lead to different shapes and patterns in the curve.

What can the rotation curve of a cluster tell us about dark matter?

The rotation curve of a cluster can provide evidence for the presence of dark matter within the cluster. If the curve shows a discrepancy between the expected rotational velocities based on visible matter and the actual observed velocities, it suggests the presence of unseen mass, which is likely to be dark matter.

How is the rotation curve of a cluster measured?

The rotation curve of a cluster is measured using spectroscopy, which involves analyzing the light emitted by the individual galaxies within the cluster. By measuring the Doppler shifts of this light, scientists can determine the rotational velocities of the galaxies and plot them on a graph.

What other information can we learn from the rotation curve of a cluster?

The rotation curve of a cluster can also provide insights into the dynamics and evolution of the cluster, such as the presence of substructures or interactions between galaxies. It can also help us understand the overall structure and mass distribution of the cluster, which can have implications for cosmological theories.

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