On Sunday, July 24, 2016 at 3:00:59 PM UTC-4, Jos Bergervoet wrote:

Actually, the text in the paper goes like this:
".. if indeed the LIGO discovery is indicative of
PBHs making up the DM, .." (p2, last paragraph).
http://arxiv.org/abs/1605.04023
And for *those* black holes we can say that 4 of
them have been observed.


Also we have a very large number (at least 100 billion) MACHOs that
have been detected via microlensing. Andrew Gould published a paper
(ApJ, I think) that explored possible candidates and came to the
conclusion that primordial black holes were the best candidate.

We should await further observational evidence before deciding
whether or not PBHs are the dark matter.

Fixed ideas based on assumptions are really not a good idea in science.

RLO
http://www3.amherst.edu/~rloldershaw

[[Mod. note -- If you could post a reference to the exact paper you're
referring to, that would be helpful. Andrew Gould has written a lot of
papers, but a quick google scholar search just now for author "Gould",
journal "Astrophysical Journal", containing exact phrase "primordial
black hole", turned up three references none of which look the one
you're referring to.
-- jt]]