Quote:
Originally Posted by Renato1
Any idea how to actually get the paper for free discussed in the abstract in Item 5?
Are there any UCDs that can be glimpsed with an 8 or 14" telescope?
If there are all these NSCs in the middle of other spiral galaxies, I wonder how come they are all hidden in ours (assuming they are different in nature from the bluish, young open clusters that look like globular clusters that are to be found around the Magellanic Clouds).
Regards,
Renato
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You can get the draft of the paper by clicking on "arxiv preprint" and then downloading the pdf after another webpage has come up.
For papers older than 'sometime in 2012', it is often possible to get the final published paper by clicking on
'' full refereed journal article"
Your question about Ultra Compact Dwarf galaxies and Nuclear Star Clusters and supermassive young star clusters, and whether or not any of these objects can be glimpsed in the amateur telescope, is an interesting one. I will see if I can find the necessary information.
I believe that the two brightest star clusters in the nearby starburst Dwarf galaxy NGC 1569 have actually been seen by visual observers.
The nuclei of dwarf elliptical galaxies are also another 'possible' for amateur observation.
Mostly, extragalactic 'standard old globulars' are disappointingly 'out of reach' for visual observation, anywhere outside of the Local Group of Galaxies (= MW + M31 plus hangers on), with the possible exception of the brightest globulars of NGC 5128;
however, the most luminous Ultra Compact Dwarf galaxies and Nuclear Star Clusters can be several mags more luminous than even the biggest globular cluster.
The visual magnitude of the Ultra Compact Dwarf galaxy associated with the Sombrero is 17.6, which is still largely out of reach for visual obs. with standard amateur telescopes.
Incidentally, it now seems that the UCDs are probably just over-extended and exceedingly massive star clusters.
Q.
your question on visibility of nuclear star clusters in big Sbc and Sc spirals like the Milky Way Galaxy.
A.
High mass galaxies like the Milky Way tend to have a large population of interstellar dust grains that scatter and absorb the light of objects behind them, so it can be very hard to see nuclear star clusters in them;
even at the most favourable orientation for reducing extinction of light by interstellar dust (a face-on spiral), there can be two or more magns of extinction in front of a nuclear star cluster in one of these giant galaxies.
Therefore, NSCs are more easily viewed in smaller galaxies, because they have much less obscuring dust in their interstellar medium. Galaxies like NGC 7793 and NGC 300 and NGC 4449 are a couple of magns down in luminosity from the MW, and they are much less dusty.....therefore the NSCs are much easier to see in them.