Op zondag 13 maart 2016 13:42:22 UTC+1 schreef Phillip Helbig (undress to reply):
In article , Nicolaas Vroom
writes:

http://arxiv.org/abs/1603.00464

Title: Did LIGO detect dark matter?

The interesting part about the article is that nowhere they mention
the words baryonic versus nonbaryonic. Instead what they use are the
concepts dark matter (7x) versus luminous matter (3x).
This are typical a human based concepts and IMO should not be used.
In a certain sense because we can not see BH's, by definition
we should call BH: dark-matter-hole's

These days, dark-matter almost universally (pun, as always, intended)
means non-baryonic matter.
I fully agree. However this has nothing to do with BH's. The problem
is I find the name BH's rather misleading. The issue is that what
Ligo detect is that there are very small objects with relative large masses.

Due to the no-hair theorem, we cannot say
whether these black holes formed from baryonic or non-baryonic matter;
The no-hair theorem as far as I understand makes certain claims
about three parameters of BH's and nothing related to baryonic versus
non-baryonic matter.
See: https://en.wikipedia.org/wiki/No-hair_theorem
That means the no-hair theorem cannot be used in this context.
To find an answer the first step is to answer a related question:
Is our Sun baryonic or non-baryonic?
If the answer is baryonic than the most logical answer is
that BH's are also baryonic.
That does not mean that small BH's like discovered by LIGO could
not solely be made from non-baryonic matter. In fact in the disc of
a galaxy there could be millions of these small BH's which could
be used to explain the missing matter in a Galaxy based on its
Galaxy Rotation curve.

That being the case we should expect also BH mergers within our Galaxy.

Nicolaas Vroom
http://users.pandora.be/nicvroom/

[Mod. note: apologies for the delay in posting this and the next few
submissions due to technical issues with the news server. -- mjh]