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VanderL
2004-Apr-01, 09:27 AM
Here is a report on minigalaxies
http://spaceflightnow.com/news/n0403/31minigalaxies/

They look like stars and because of their redshifts they needed to be placed much further away, turning them into mini galaxies 150 ly across. Are these object really minigalaxies, or could they be nearby stars with excess redshifts?

Cheers.

antoniseb
2004-Apr-01, 05:19 PM
Originally posted by VanderL@Apr 1 2004, 09:27 AM
Are these object really minigalaxies, or could they be nearby stars with excess redshifts?
It would be quite a coincidence for eight nearby stars to have an excess red-shift [of unknown origin] that matches the redshift of the Virgo cluster against which they are superimposed from OUR point of view.

I haven't read the details, but I'm sure it's likely that there are other good reasons to assume they are mini-galaxies with diameters about 150 light-years. I bet that when we study them with future instruments we find they have central black holes in the ten thousand solar mass range.

VanderL
2004-Apr-01, 05:28 PM
It would be quite a coincidence for eight nearby stars to have an excess red-shift [of unknown origin] that matches the redshift of the Virgo cluster against which they are superimposed from OUR point of view.

Well, they didn't look anywhere else, so maybe there are a lot more of those objects.
As you say galaxies are different from stars, spectrometrically. But I didn't see any mention of other characteristics here http://astro.ph.unimelb.edu.au/~mdrinkwa/f...rnax/globulars/ (http://astro.ph.unimelb.edu.au/~mdrinkwa/fornax/globulars/)

So, I wonder what those other indications are, or if this redshift is the only reason they are classified as mini-galaxies.

Cheers.