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Questions tagged [galactic-dynamics]

Questions regarding interactions between galaxies or between major parts of a galaxy.

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How many galaxies are currently merging?

On the homepage of the galaxies research group at CfA SAO, it states, "Astronomers discovered that as many as 25% of galaxies are currently merging with others." They do not provide a ...
Daddy Kropotkin's user avatar
6 votes
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Are metallicities of molecular clouds lower in the outskirts of the galaxy?

(this question was originally posted in an answer by user PSR-1937-21 to another post. I find it an interesting one, but since they don't seem to be active anymore, I'm posting it to see if somebody ...
SE - stop firing the good guys's user avatar
5 votes
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Did the density wave theory for spiral arms take account of this phenomenon?

I came across this link. In it the author speculates that in the outer region of a galaxy, the spiral arms overtake the stars, and vice versa for the inner region. That means there must be a middle ...
longtry's user avatar
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What's the angle between the sun's galactic speed and the ecliptic?

I know the sun wobbles up and down the galactic plane around 35myr. I don't mind about that component. I'd like the know the angle between the linear speed of sun around the Milky Way (just the ...
Yuta73's user avatar
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4 votes
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Why do the Centaurus A radio jets have two "arms" each? (Event Horizon Telescope image)

Fig. 2: Image analysis of the final model: a, Model image corresponding to the image from Fig. 1 with a pixel size of 2 μas. Here, the tentative position of the jet apex is indicated with a circle. ...
uhoh's user avatar
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3 votes
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How do star orbits, density wave theory and dark matter distribution work together?

I got confused while trying to combine these 3 concepts. Would love to hear some detailed explanation. Density wave theory states that spiral arms are formed by tilted elliptic orbits. Bertrand's ...
YaaZ's user avatar
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dark matter in galaxy cluster in intergalactic space

On the rotation speed of galaxies in a galaxy cluster: -> Is the dark matter associated with each galaxy in a cluster, sufficient to explain the rotation speed of galaxies in the cluster, or extra ...
Angela's user avatar
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2 votes
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Formation scenarios for elliptical galaxies?

I am trying to get an overview of the latest research on different formation scenarios for elliptical galaxies and filter out old scenarios in the literature that are today proved to be not sufficient/...
trynerror's user avatar
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Galactic rotation speeds - questions from a non-astronomer

Are there any observations that more distant galaxies appear to rotate more slowly than closer galaxies? What methods are used to measure the rotational speed of galaxies? (both orbital speed ...
Blundervan's user avatar
2 votes
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121 views

Need help on Springel model for galaxy simulation

I am working on a code for galactic dynamics simulation. Initial conditions (positions and velocities) are based on a model with a massive dark halo and a thin exponential disk. Now, from the ...
user avatar
1 vote
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Have measurements been conducted on the position of the galactic center of mass and the orbit of the presumed black hole at the center?

Related questions have been raised before Is our central black hole actually at the CG of the galaxy? Orbiting supermassive black hole or galactic center of mass? , where explanations have been given ...
Imyaf's user avatar
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At what distance does the galactic tide significantly affect the orbit of a heliocentric object?

The title essentially explains the question. I was wondering if the galactic tide could play a role in raising perihelia of extreme trans-Neptunian objects (i.e. Sedna) versus the effect of a ...
WarpPrime's user avatar
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How to obtain the SDSS’s five-part imaging ID number for a list of galaxies whose Ra Dec is known?

I am trying to obtain the FITS file of a few hundreds galaxy from SDSS DR12 Survey. SDSS tries to download the FITS File with the link that contains the information about SDSS’s five-part imaging ID ...
B. S.'s user avatar
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Why use this density function to derive the Lane-Emden equation?

I am currently reading Binney and Tremaines Galactic Dynamics, learning about spherical systems. In chapter 4.33 a density function (Eq. 4.83) is given as: $$ f(\mathcal{E}) = \begin{cases} F \...
Squirrel's user avatar
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Can this ppxf fit work?

I am trying to do kinematical analysis of spectra using ppxf-algorithm from Capellari. The velocity dispersion I get seems to be to high and I am not sure what the reason could be. On the website of ...
trynerror's user avatar
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Is the Condor Galaxy (NGC 6872) the result of a non-collision galaxy interaction?

All the interacting galaxies that I can find are of collisions, I'm trying to find an example of a fly-by galaxy interaction. Is the Condor Galaxy an example of one? Wikipedia's NGC 6872; Possible ...
MiscellaneousUser's user avatar
1 vote
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Why we can approximate the mass of spiral galaxy like this?

This is a question from Galaxies in the Universe: An Introduction(2nd edition),Linda S.Sparke&John S. Gallagher III. As shown in the picture My question is why we can neglect the bulge of spiral ...
みえみえ's user avatar
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What new instruments "so sensitive that we can see (large circumgalactic winds) have only been on telescopes for a few years"?

The Rhodes College press release Prof. David Rupke and Team of Astrophysicists Make Major New Discovery About Galaxy Evolution links to Astronomy Community/Nature.com: The Making of Makani; The story ...
uhoh's user avatar
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1 vote
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What are Stokes parameters for galaxy shapes, how do they compare to Stokes parameters in optics?

I remember Stokes parameters as a way to completely define the polarization state of a well-defined beam of light. However several questions here refer to Stokes parameters used in characterizing the ...
uhoh's user avatar
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What is the largest cluster of merging galaxies?

Reading about the Andromeda–Milky Way collision, a galactic collision predicted to occur in about 4.5 billion years between the two galaxies, I went to the galaxy merger page and Wikipedia states that ...
Tom Sol's user avatar
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Population histograms and relationship between size of galactic disk and amount of dark matter

I am interested in seeing a plot of dark to baryonic matter ratios in terms of the galactic disk size (when it applies, as not all galaxies fit into disk shapes, and probably analyzing disk galaxies ...
lurscher's user avatar
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Looking for a Dwarf Galaxy < 500 L.y. in Diameter, which is not a Satellite / Companion, or is at least 500 000 L.y. away from another Galaxy

My goal is to learn about an example of a Dwarf Spheroidal or a Dwarf Irregular Galaxy which is not a Satellite / Companion Galaxy (or is at least 500 000 L.y. away from another Galaxy), and doesn't ...
user23236's user avatar
1 vote
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135 views

Virial coefficient when computing dynamical mass enclosed by a rotating galactic disk of gas

Suppose I have a large thin disk of rotating gas in a galaxy -- the disk has a maximum inclination-corrected $V_{max}$ and a maximum radial extent of $R_{max}$ corresponding to that $V_{max}$ ...
quantumflash's user avatar
0 votes
1 answer
74 views

The distribution of mass in the bullet cluster

Can someone point me to a database which contains the luminous and gas mass distribution of the bullet cluster?
Angela's user avatar
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