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CraigS
30-11-2010, 07:12 AM
In the News (and continuing on our Black Hole theme we seem to have running at the moment): scientists are speculating about the symbiotic relationship between Super Massive Black hole growth and Galaxy formation.

Astronomy without a telescope - black hole evolution (http://www.physorg.com/news/2010-11-astronomy-telescope-black-hole.html)



For the record, a nice summary of the present status of the observational supporting 'evidence' for SMBHs is:

i) the mass of a galactic bulge is generally inferred from the velocity dispersion of its stars;
ii) the presence of supermassive black holes in the centre of such bulges is inferred from the very fast radial motion of inner stars (at least in closer galaxies where we can observe individual stars);

For galaxies too far away to observe individual stars:

iii) the velocity dispersion and the presence of a central supermassive black hole are both inferred, drawing on the what we have learnt from closer galaxies;
iv) direct observations of broad emission lines are interpreted as the product of very rapid orbital movement of gas around an SMBH (where the ‘broadening’ of these lines is a result of the Doppler effect).

Overall, despite the assumptions built on assumptions nature of this work, ongoing observations continue to support and hence strengthen the theoretical model.

Cheers

Robh
30-11-2010, 11:22 PM
Can't let something as interesting as this slip by.
It seem's black holes are popping up everywhere in these threads.

If indeed supermassive black holes are found in the centres of every galaxy, one would have to think there was a connection to galactic evolution. People will argue that their mass is only a small fraction of the whole galaxy's mass but remember the butterfly effect.

Regards, Rob