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.

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10
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3answers
2k views

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 ...
0
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0answers
13 views

Do higher-metallicity elliptical galaxies, that formed rapidly, have a larger velocity dispersion (lowercase-sigma)?

https://academic.oup.com/mnras/article/445/3/3092/1036122?login=true And, ..... https://www.newscientist.com/article/mg24933160-200-how-every-galaxy-comes-from-quantum-fluctuations-billions-of-years-...
2
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0answers
50 views

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
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2answers
331 views

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 ...
3
votes
0answers
83 views

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? ...
2
votes
1answer
358 views

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?