100 solar mass BH in Orion?

PAllen

This paper proposes a 100 solar mass black hole in nearby Orion Nebula:

http://arxiv.org/abs/1209.2114

Exciting if true. I have no particular comments, just thought it should be noted here.

Greg Bernhardt

What is the largest we've found so far?

Max™

Wouldn't that be the other way around? We've found lots of huge ones, I'm curious what the smallest we've found is.

PAllen

Previously, what were hypothesized were huge, galactic center BH (many thousands to billions of solar masses), and stellar black holes (say 3 to 30 solar masses). This represents a new and unexpected size, as well as being close (relatively). [I mistakenly assumed this back ground would be well known here.]

Max™

Well, I did actually know about the large ones, and I remember some buzz about midrange holes being proposed for certain unusual xray sources, but yeah the main thing that is interesting here is how close it is, right around the corner, galactically speaking.

PAllen

x-ray sources are presumed stellar mass BH, e.g. from remnant of supernova. This one, bigger than stellar, not associated with galactic nucleus, is wholly unexpected, so far as I know.

SHISHKABOB

I believe that intermediate size black holes are also interesting because we don't have a good idea as to how they are formed

stargazer3

As I can remember, we have only one example of an intermediate one. Low mass and smbh-s are quite abundant.

Max™

I was thinking of these: http://www.nasa.gov/mission_pages/sw...ous-Xrays.html

PAllen

Yes, they seem to be hypothesizing the same sort of thing as claimed in the paper I linked in post #1. Except the new one is close and has more direct evidence. Due to proximity, a variety of direct observational tests may be possible.

Chronos

Actually, small black holes [< 5 solar mass] are quite scarce [as in almost nonexistent]. I find the apparent mass gap between the largest neutron stars and smallest black holes to be very curious.

SHISHKABOB

would that be because it's difficult to detect stellar mass black holes, and so we don't have a lot of examples of them?

Chronos

It appears possible solar mass black holes do not directly result from the collapse of massive stars. We have already seen examples of 20+ solar mass stars collapsing to form neutron stars. It may be they require more exotic [and rare] events like neutron star mergers.

SHISHKABOB

oh wow really? I thought it was well accepted that massive stars above around 8 solar masses end up going supernova and forming black holes.

D H

Exactly. There are only 20 to 30 or so objects that are deemed to be strong candidates for stellar mass black holes. It's a small list.

D H

It is well accepted that stars above about 8 10 or so solar masses end up going supernova. Stars between 0.5 solar masses and 10 solar masses end up as white dwarfs. It's only the massive stars that die a spectacular death. The result of that death can be a neutron star plus a bunch of ejecta, a black hole plus a bunch of ejecta, just a bunch of ejecta, or just a black hole and hardly any ejecta. Stars between 10 to 25 solar masses do go supernova, but the supernova ends up ejecting almost everything. The small core that is left is too small to undergo a complete gravitational collapse. It instead becomes a neutron star.

ImaLooser

The smallest known is 4 solar masses. This is puzzling, because the largest known neutron star is 1.97 solar masses. Why the gap? No one knows.