So, since I have been, like, actually organizeering black hole stuff over the last couple of weeks, one might wonder what is up with black holes?
Well, I can't really talk about the really cool stuff, yet, but there were some interesting news:
- NGC 3758 has two black holes about 10,000 light years apart.
So, recent merger, has some ways to go, seen others like it before, but nice clean convincing result.With pretty pictures and bonus animation (see link above)
- Swift also saw an interesting series of x-ray flares almost certainly from a tidal disruption of a star by a modest supermassive black hole
I'm inclined to the tidal disruption explanation, though the scenario requires the event be viewed near pole on and involve relativistic jets, but that just makes it cooler.
Some accretion disk instability could be involved instead.Bloom et al 2011
Levan et al 2011- Stacked Chandra images of z > 6 galaxies suggest that moderate mass supermassive black holes were common at early times, possibly consistent with supermassive black holes forming from 100,000 solar mass seeds formed by direct collapse.
Now we just have to figure out how that happens.Yup, cool animation at link, and figures galore:
- Stacked Chandra images of z > 6 galaxies suggest that moderate mass supermassive black holes were common at early times, possibly consistent with supermassive black holes forming from 100,000 solar mass seeds formed by direct collapse.
- Best for last:
"A Large Systematic Search for Recoiling and Close Supermassive Binary Black Holes" Eracleous et al
This is a monster paper, and not one for pretty pictures, reporting multi-epoch spectroscopic survey of active galaxies with certain spectral peculiarities, in particular emission lines with high velocity offsets.
IF these spectra are due to close binary supermassive black holes, then some of these systems should show orbital acceleration - shift in the velocity offsets of the emission lines.
By close they mean less than a parsec, in the range where gravitational radiation will soon take over the orbital evolution and the black holes will coalesce.Watch that space, it ain't done.
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What is a moderate mass supermassive black hole?
A fair question, Tom, since that turn of phrase does sound as oxymoronic as "jumbo shrimp".
Most supermassive black holes are 1M M_sun or above. The contrast is with stellar mass black holes (1-100 M_sun). Not much has been found in the intermediate range so far--Ethan mentioned something recently, and now Steinn reports a claim of 100k M_sun black holes. Presumably these black holes will end up over 1M M_sun through mergers or accretion, so functionally (but not definitionally) they are supermassive black holes. I think this is what Steinn means.
@TomS - my apologies. Supermassive Black Holes generally are in million to billion solar mass range - although people really take them from 100,000 to 10 billion solar masses as needed.
By "moderate mass" I meant down around a million solar masses, not right at the bottom of the range, but not the 100+ million solar mass black holes that power bright quasars etc.
I know this comment has nothing to deal with the answer to "What is a moderate mass supermassive black hole?", but reading this, and implying previous knowledge of black holes, it made me think.... We all know/think that light cannot escape the gravitational pull of a black hole and lights photons begin to distort and rip apart. But photons have recently been theorized to be two places at once, where the photon is at both the birth of the photon, and where it ends. What I theorized is that light itself, if it is at two places at once can also have two charges to the same light photon, a positive and negative, but still the same light. so if that photon in theory, gets ripped apart at one end... it's still the same photon, so it happens on the other end. eliminating the light completely... right?