Questions tagged [galactic-evolution]

Questions about the formation of galaxies, the way they change over time, and the processes that have generated the structures observed in nearby galaxies.

Filter by
Sorted by
Tagged with
2 votes
1 answer

Why do stars orbit much faster than gas in galaxies?

The velocity dispersion of gas within galaxies is typically 30-40 km/s. Stars are born in gas clouds. But later on, their orbital velocities reach several hundreds of km/s. How is this possible? Where ...
6 votes
0 answers

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 ...
3 votes
3 answers

What physical process can Metallicity(Z) of a galaxy tell us?

For example, if there is a galaxy and its metallicity increase or decrease from high redshift to present day (We can see it from simulation like TNG or EAGLE). What physical process we can know? ...
7 votes
1 answer

Why wouldn't an elliptical galaxy collapse back into a spiral galaxy?

I should preface this post with two parts of my tentative (probably wrong) understanding first. First, it's been told to me that spiral galaxies typically form first, and then elliptical galaxies ...
4 votes
1 answer

Using cosmological model GADGET - 4

I want to use GADGET-4 "a parallel cosmological N-body and SPH code meant for simulations of cosmic structure formation and calculations relevant for galaxy evolution and galactic dynamics" ...
3 votes
1 answer

Evaluating Potentials using Galpy

I am trying to model galactic disks. From the past research we have discovered that the halo follows the logarithmic potential, the disk follows the Miyamoto-Nagai potential and the bulge follows the ...
-2 votes
1 answer

Is the solar system the only survivor of cosmic evolution? [closed]

A question has entered my mind, we know that all the phenomena in the universe are several thousand light years away from us, so the light we see from them is related to the past few years, now my ...
10 votes
3 answers

How do we know that supermassive black holes can gain mass by means other than merging with other supermassive black holes?

I just stumbled across the following answer "update" from 2013: This just in, recent observations have ruled out the possibility that SMBHs gain mass only through merging with other black ...
  • 31.1k
2 votes
0 answers

Can Quasars generate Heavy Elements?

Pretty sure Quasars were involved in increasing Galactic metallicity but is there evidence of quasar AGN's generating heavy elements, such as radioactive ones and shooting them across the universe in ...
12 votes
2 answers

Why aren't there blue elliptical galaxies or yellow spiral galaxies?

Elliptical galaxies are universally old and yellow; about three-quarters of all ellipticals have no significant star-forming gas or dust left, and even the quarter or so of ellipticals that are still ...
  • 625
3 votes
0 answers

Is there a galactic main sequence?

Stars can be plotted on an HR diagram, on which a main sequence is apparent, and stellar evolution can be plotted on on such a diagram as a function of mass. Is there an analog for galactic evolution? ...
  • 17.1k
2 votes
1 answer

Is there a strict chronological order that determines the shape of galaxies?

Assuming no collision happens, do all elliptical galaxies eventually become spiral? Also, when a galaxy becomes spiral or barred spiral, can it switch between these shapes or is it set forever?
  • 143