All Questions
14
questions
1
vote
0
answers
97
views
Deriving the Tully-Fisher relation from the virial theorem
So I know this is a loose proof and a lot of assumptions are made, but I do not understand how these assumptions lead to the quantities we obtain so I will be asking questions at each step:
start with ...
- 171
3
votes
0
answers
30
views
How to find x-values of fourier-transformed correlation functions in velocity space?
I am trying to extract the kinematic parameters (rotation velocity, velocity dispersion, ...) of an elliptical galaxy by extracting the kinematical broadening function using the FCQ-Algortihm first ...
- 849
4
votes
1
answer
265
views
How to calculate mean line of sight velocity of stars after rotation of galaxy?
I am trying to calculate the mean line of sight velocity from a simulation snapshot of a galaxy after the galaxy is inclined by a certain angle, theta. I am coding it in python.
What I have done so ...
- 155
0
votes
1
answer
145
views
can i use heliocentric velocity as a rotation speed? [closed]
In the research of the galaxies, does heliocentric velocity involves space's expanding velocity? and can i use heliocentric velocity by galaxy's rotation speed?
- 33
0
votes
2
answers
286
views
How can we calculate velocity of an object given the distance from an object in parsecs?
If you had the distance from a celestial object, in parsecs, how would you calculate the velocity of the said object?
Edit: I'm sorry I don't have more context, the specific questions is: "A galaxy ...
- 11
5
votes
1
answer
1k
views
How to determine the mass of a galaxy?
I am having a slight disagreement with my professor.
We can measure the mass of a distant star cluster from:
A.Its color
B.Its radius
C.Its metallicity
D.Smearing of lines in its total spectrum
My ...
- 67
8
votes
2
answers
312
views
Can "rogue" supermassive black holes be made this way?
Could two galaxies (one big and one small)intersect at a velocity to allow the smaller black hole to escape but not the galaxy around it?
- 1
1
vote
2
answers
1k
views
What is the fastest a galaxy or other body has been measured to (or can) travel?
Our solar system travels at an average speed of 515,000 mph and our galaxy at 1.3 million mph through space. What is the fastest moving body in space recorded and the fastest can a black hole or ...
- 1
6
votes
2
answers
743
views
Is there a rough analytical expression for the Milky Way's radial mass distribution?
I found the image below in Space.com's article This 3D Color Map of 1.7 Billion Stars in the Milky Way Is the Best Ever Made, although it is not the map mentioned in the title.
The caption for this ...
- 30.7k
11
votes
1
answer
9k
views
What does the velocity dispersion of a galaxy mean?
Also, what is the advantage of getting information about the velocity dispersion of a galaxy?
- 113
10
votes
2
answers
2k
views
What (actually) is the " deprojected half-light radius" of this almost-all-dark-matter Galaxy?
The recent news of the Ultra Diffuse Galaxy (UDG) Dragonfly 44 is an excellent example of what could be termed 'observe different' thinking. The dragonfly telescope is noted not for the size of its ...
- 30.7k
1
vote
1
answer
250
views
Question regarding the Milky Way when calculating galactic space velocities for galaxies
I have been calculating galaxy space velocities (where proper motions are known) in order to measure their orbits of the Milky Way using the method proposed in the appendix of http://www.aanda.org/...
- 147
2
votes
1
answer
94
views
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 ...
- 147
12
votes
1
answer
662
views
How do we calculate the escape velocity of galaxies?
How do we calculate the escape velocity of galaxies?
Do we have to know the total mass?
What is the escape velocity for Milky Way?
- 283