Questions tagged [galaxy-cluster]
Questions regarding gravitationally bound systems of hundreds to thousands of galaxies as well as interactions between such systems.
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Efficiently calculating power spectra from galaxy catalogs
I am dealing with a problem which requires calculating either the correlation function or the power spectrum. At times, the 2-point-correlator seems the better route, at others, the PS. Right now I am ...
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Generating random galaxy catalogs for correlation functions
The galaxy correlation function, when computed directly from a galaxy catalog, relies on computing a randomly generated counterpart catalog.
When dealing with a simulated galaxy mock-catalog, where ...
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Are there small voids of 10 - 20 megaparsecs also within, and not only between superclusters?
I sincerely apologize if this question is stupid, however after all the articles I read so far, I could not confirm this assumption, which I think is actually a fact, but I'm not completely confident.
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Does the Milky Way belong to a Galaxy cluster
I know that the Milky Way is a member of the Local Group and the Virgo Supercluster / Laniakea Supercluster. However, I can't seem to find any information about the Galaxy cluster we belong to.
Does ...
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To what extent do the spin of smaller celestial bodies reflect the spin of the larger system’s of which they are a part?
One can ask whether two objects are spinning in the same direction or not. For example, the Sun, Earth, Luna, most of our solar planets (except Venus and Uranus), and the planets’ satellites all spin ...
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false to stable vacuum transition [closed]
if the universe transitioned from a meta-stable vacuum to a stable vacuum we assume a universal death scenario. However since it cannot propagate faster than the speed of light, from any particular ...
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Is it possible for galaxy clusters to interact?
Galaxies commonly interact and collide with other galaxies. Is it possible that clusters of galaxies similarly interact and collide? Have people tried to study this phenomenon previously? I couldn't ...
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Will galactic filament indefinitely expand while its galaxy clusters indefinitely disperse?
Exciting discoveries of weak gravitational lensing suggest the existence of galactic filaments made of dark matter that are the size of galactic superclusters. My questions involves the future of the ...
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Does the Abell 1689 supercluster have angular momentum?
The Abell 1689 is a large group of galaxies, containing a lot of elliptical galaxies :
https://en.wikipedia.org/wiki/Abell_1689
Usually, an elliptical galaxy don't have large angular momentum around ...
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How long will it be until the nearby groups of galaxies are receding at speeds faster than light?
And subsequently how long will it be until we can never see them again?
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What's the density of dark matter (clouds)?
How much mass per unit volume do known dark matter have, for instance in the Bullet Cluster? Does the density vary in space, for example, do individual dark matter structures have denser cores?
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Why does the concentration-mass relation of galaxy clusters have a negative slope?
As reported in some recent observational works works (ref. Merten et al. 2015) the concentration-mass relation of galaxy clusters has a negative slope. This means that at a fixed redshift, haloes with ...
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Fingers of God effect for galaxy clusters
Galaxies that reside in galaxy clusters are know to have peculiar velocities that cause the Fingers of God effect.
But what about galaxy clusters themselves?
Do they also have peculiar velocites ...
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Centre (projected) of a galaxy cluster
A galaxy cluster consists of somewhere around a few tens to several hundred galaxies.
To measure the position of a galaxy cluster, i.e. it's RA and DEC, do astronomers always assume it to be its ...
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Difference in the baryon acoustic oscillation measurements
I understand from this Wikipedia page about baryon acoustic oscillations (BAOs). I can also see that BAO measurements were first detected using luminous red galaxy samples.
Now, many papers use ...
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What is the role of the random catalogue in calculating the two-point correlation function?
To study clustering of galaxies and clusters, one makes use of
the two-point correlation function. However, we can see that all
the estimators of $\xi(r)$ use a random catalogue.
What is the random ...
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How to find out if a galaxy is in a specific cluster
I am trying to find out how to find out if a certain galaxy is located inside a cluster. For the famous ones this is quite easy (sometimes even on wikipedia!), but I haven't been able to do it for ...
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Would gravitational waves be subject to external gravitational perturbations?
Given that the gravitational wave detected by LIGO was a very weak echo of a very distant event, could it have been "deviated" and distorted on its way here by a sufficiently massive black hole in ...
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Are 3D coordinate data from Sloan DSS-III available & easily accessible to non-pros?
Of course the newly announced SDSS-III data and maps from the Sloan Digital Sky Survey with 1.2 million objects, along with all previous data sets are openly available, and I'm sure there are many ...
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How do I modify redshifts to gain corrected line of sight velocities?
I'm currently trying to collect the data to run an N-body simulation for 11 of the galaxies in the Local Group where proper motions are known, however I don't understand how to get the required line ...
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Initially non-flat space-time makes dark matter obsolete$\dots$
After the Big Bang, dark matter clusters and build the seeds for visible matter, that then forms stars, planet, you, me, everybody...
But do we really need dark matter to build cluster first. What if ...
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Is our supercluster part of a galaxy filament?
It was discovered recently that the Milky Way galaxy lies inside a supercluster named Laniakea Supercluster. On the other hand, wikipedia says that galaxy filaments are "the largest known structures ...
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Can "dark matter" be the additional mass from the speed of the Galactic Cluster?
Considering that the Earth orbits the Sun at 100 000 km/h and that the Sun orbits the Milky Way at almost 1 000 000 km/h, could it be possible that the galactic cluster orbits some super cluster at ...
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What accounts into calculating the Hubble constant?
From my understanding, the Hubble constant $H_0$ calculates from observed redshifts $z$ of distant galaxys against their proper distance $D$. The current value appears to be 67.80(77) $\frac{km}{s}Mpc^...
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Are high-speed galactic collisions survivable?
This is a hypothetical question, but it really is meant as a vivid way of asking about the affects of high-speed galactic collisions. The November 27 APOD showed the Cheshire Cat galaxy group, and the ...
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Radial Density Profile Equation [closed]
The Virgo Galaxy Cluster has a mass of $10^{14} M_{\odot}$ and its centre is $16Mpc$ from Earth. The large elliptical galaxy $M87$ lies at the centre of the Virgo cluster. $M87$ has a supermassive ...
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Temperature of the intracluster medium (ICM)
I've read once in an article that the temperature of the medium within galaxy clusters (the intracluster medium or ICM) is extremely high.
What does that temperature really mean? Particle velocity?
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H-alpha velocity fields of spirals falling into a cluster
What kind of impact would you expect ram pressure stripping / tidal interactions / harassment / interactions with the cluster potential (etc!) to have on the h-alpha velocity fields of infalling ...
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Concerning fate of Milky Way Galaxy
Andromeda Galaxy is the largest galaxy in the galaxy cluster[1] called Local Group[2] and our Milky Way Galaxy as well as some satellite/dwarf galaxies are orbiting around each other within Local ...
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what is the current explanation for the formation of cosmic voids?
Why aren't galaxies distributed evenly in space, but instead form those sponge-like structures, with huge voids between filaments?
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How many galaxies are there in the Hercules–Corona Borealis Great Wall?
The Hercules–Corona Borealis Great Wall is "to date (February 16, 2015), it is the largest and the most massive structure known in the observable universe" (source). How many galaxies is the Hercules–...
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When will the Milky Way "arrive" at the Great Attractor, and what all happen then?
The Great Attractor is described as a location to towards which the Milky Way, along with all other galaxies in the Laniakea Supercluster are moving. How long will it take for the Milky Way to "arrive"...
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Is there a paper on galaxy mergers in clusters of galaxies?
I'm looking for something to cite about galaxy mergers in clusters of galaxies.
I need numbers on the frequency of mergers in the outer parts of galaxy clusters vs. the cluster center. In the center ...
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Beta profile fit of Virgo cluster gas?
I'm looking for the parameters $r_c$, $\rho_0$ and $\beta$ in a $\beta$-profile fit of the Virgo cluster's ICM density. I just can't find a reference for it. Unlike for Coma (Abell 1656) where it's in ...
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Estimating the tangential and cross component of the galaxy's shear using Gnomonic projection
I would like to know how I can estimate the tangential and cross component of the galaxy's shear using Gnomonic projection
of the right ascension and declination the galaxies relate to the center of ...
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Is the Hubble Ultra-Deep Field image representative of the entire sky?
The Hubble ultra-deep field image is a photograph of an area of sky equivalent to a 1mm x 1mm piece of paper held a metre away from the eye (one thirteen millionth of the entire sky). It contains an ...
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Is the local group bound to the Virgo cluster?
The Virgo Cluster is currently red-shifted by 0.003 according to Wikipedia; this indicates that the cluster is expanding. Will the cluster's enormous gravity eventually "win" and pull the ...
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Contradict the expansion of the universe?
Lets say that we observe in a distant galaxy cluster, which in all the galaxies move far away from us.
and here we see in the same cluster a galaxy that move away from us in a much lower velocity ...
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How are Galaxy Super Clusters Generated
I have seen pictures of clusters of galaxies, usually used in regards to theories of dark matter and galaxy formations. One of the most famous ones has the perceived shape of a stick-figure. If I am ...
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What is the ultimate fate of a cluster of galaxies?
We're fairly aware clusters of galaxies drift apart due to space expansion, which will drive them out of each other's cosmic event horizon eventually, leaving them separate, alone, each a single "body"...
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