In other terms, did galaxies grow around black holes at their center?
1 Answer
Note: I am not an astrophysicist. If someone with the relevant expertise finds my analysis of the source paper to be invalid, I would appreciate your help with correcting my answer here.
This is a somewhat complicated question to answer. Black holes may precede galaxies in the form of primordial black holes which according to some models arose in the early Universe from quantum fluctuations. Primordial black holes are currently hypothetical. Supermassive black holes (that you find at the center of galaxies) may not come from these, however. There are a few possible ways that supermassive black holes may have formed:
- Molecular cloud / dwarf galaxies collapsing to form supermassive stars (SMS) which later further collapsed into supermassive black holes (SMBH)
- Dwarf galaxies forming massive stars which collapse into massive black holes, which later coalesce into SMBHs
- Primordial black holes accreting sufficient matter to become massive black holes, which later coalesce into SMBHs
Depending on how strictly you define "galaxy" it does seem most likely that the supermassive black holes formed inside early galaxies, but a type of black hole (primordial black holes) may have preceded galaxies.
Source:
UPDATE 10/21/2013:
This just in, recent observations have ruled out the possibility that SMBHs gain mass only through merging with other black holes. For more, see this Astronomy.com article.
-
1$\begingroup$ As far as I understand, question as to whether or not primordial black holes exist is still very much on the table. $\endgroup$ May 11, 2021 at 15:00
-
1$\begingroup$ @f_n_lyre you are correct, the existence of primordial black holes is speculative $\endgroup$ May 11, 2021 at 16:51
-
1$\begingroup$ @f_n_lyre Edited to reflect the hypothetical nature of primordial black holes $\endgroup$– called2voyage ♦May 11, 2021 at 16:57
-
$\begingroup$ I've just asked How do we know that supermassive black holes can gain mass by means other than merging with other supermassive black holes? $\endgroup$– uhohMay 16, 2021 at 2:50