On Tue, 6 Jan 2004, Bartosz Lew wrote:

ok, maeybe I messed something up ;)

yep ;)

the whole question is whether we are talking about *stellar* matter or *nbCDM*

but the bottomline still is that UCD are very cuspy ;)

they are very cuspy *stellar* matter (gwiazd)

but what's with their halo - something that the host galaxy was involved that's all I know

yep. the observations seem to show that they have nearly zero nbCDM, neither cuspy, nor non-cuspy.

So the question in that paper is: how did they lose all their nbCDM?

The simulations show that if the UCDs early on had very low concentrations of nbCDM, then it's fairly easy to show how these low-concentration haloes around the UCDs were destroyed in tidal interactions.

However, N-body simulations on cosmo length scales give fairly high concentrations of nbCDM for these UCDs, and so standard CDM theory seems to imply that UCDs *should* still have concentrated CDM haloes.

But the observations show they seem to have no haloes at all.

b

here's the article astro-ph/0307362

bart.

ps. if ths came to you twice - sorry for that