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Super massive black hole

  1. Dec 17, 2012 #1
    Hello All,

    It says that, if we discover every galaxy, then there is a super massive black hole, present in each galactic centre.

    Is there any physical rule for that?

    I mean to say, a galaxy rotates with x,y,z.....rules, the gravitational force is such and such.......

    So, the formation of the super massive black hole must following a rule according to the laws of nature. What is that?

    Thanks for help.

    -- Shounak
  2. jcsd
  3. Dec 17, 2012 #2
    Most Galaxies have a super massive Blackhole, as far as I know to date they are still not sure all galaxies have a super massive blackhole. However I am not sure if thats changed yet or not. Not sure how to answer your other question as per a rule.
  4. Dec 21, 2012 #3


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    I agree w/ all of that and I would add that I AM sure that there has not as yet been any discovery of a "rule" regarding galaxy formation around super-massive black holes simply because that would be big news indeed and we would all have heard of it.

    The evidence to date seems to be pointing that way and it will be interesting to see if any such rule does evolve out of the evidence as we accumulate more.
  5. Dec 21, 2012 #4


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    It appears super massive black holes are the rule with most galaxies. I'm unaware if it has been asserted for all galaxies. The evidence appears to suggest massive black holes seeded galaxy formation in the early universe.
  6. Dec 22, 2012 #5
    Out of the 5 bigger nearby galaxies, 3 provably contain no supermassive black holes. Neither of the Magellanic Clouds contains a massive core. Triangulum does have a dense core - which consists of perfectly ordinary stars. It is proven that no massive black holes of over 3000 solar masses can exist there.
  7. Dec 22, 2012 #6


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    Interesting. Do you remember where you read that? Could you point me to something?

  8. Dec 22, 2012 #7
    Andromeda has a black at its' centre.
  9. Dec 22, 2012 #8

    Every bright elliptical galaxy is believed to contain a super massive black hole which is related by M-Sigma relation. The mass of these galaxies are co related to the mass of the black hole.

    I made a mistake posting the name of Andromeda. It is a spiral galaxy, so it does not follow the M-Sigma relation.
    As Chronos have rightly pointed out that it is seeded in the formation of the galaxies.

    However it is still unclear with the M-Sigma relation that many elliptical galaxies do not contain black holes. Might be their masses are too low, with the value suggested by the M-Sigma relation......Or the data provided is insufficient to prove the presence of black hole.

    Sagittarius Dwarf Elliptical galaxy the 2nd.closest to Milky Way, but as per my reading it does not have a black hole.

    I made a mistake by mentioning the name of Andromeda. It is a spiral galaxy and hence does not follow the M-Sigma relation.

    Any further views......

    -- Shounak
  10. Dec 22, 2012 #9

    This article seems to suggest that the object at the center of the Triangulum Galaxy is no more then 3,000 solar masses.
  11. Dec 23, 2012 #10


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    Thanks for the post, but that article states an uncertainty up to 20,000 solar masses and they even say that they can't rule out similary galaxy formation to those that do have a supermassive BH.

    I was looking for something definitive as stated by snorkack who said categorically "Out of the 5 bigger nearby galaxies, 3 provably contain no supermassive black holes". I'm interested in seeing the proof. I'm not doubting it, but neither am I convinced by a statement with no backup.
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