Hello Space Fans and welcome to another edition of Space Fan News.
This week, astronomers using the Hobby-Eberly telescope at the University of Texas and the
Hubble Space Telescope have announced the discovery of one of - if not the - largest
black hole ever found.
Now this should sound familiar to you because about this time last year, in Space Fan News
#43, I told you about a similar discovery of the largest blacks holes ever found at
the time anyway.
In that episode I reported that two galaxies, NGC 3842 had a ten billion solar mass black
hole at its center, and NGC 4489 had a comparable or even larger one at its center.
Click on the link in the description box to get more details about that, but both of those
galaxies were ellipticals, the largest and oldest galaxies in the universe.
Elliptical galaxies are usually orange in color because they are forming no new stars,
which usually makes galaxies bluer. Ellipticals are so big because they have spent their lives
merging with other galaxies collecting stars and colliding with the central black holes
of other galaxies to make the enormous black holes we see at their centers.
One thing you've heard me say many times is that most massive galaxies we've observed
have supermassive black holes at their centers, but what you may not know is that the masses
of the black holes are believed to correlate with properties of the host-galaxy's mass.
Observations of hundreds of galaxies have shown the correlation to be that supermassive
black holes are about, on average, 0.1 percent the total mass of the host galaxy.
No one knows for sure how big black holes can get as far as an upper limit goes, but
they've always found this correlation of about 0.1 percent the mass of its host galaxy.
You got all that? OK, so here we go…
This discovery announced this week from the Max Planck Insitute from Astronomy and the
University of Texas found a 17 billion solar mass black hole at the center of the lenticular
galaxy NCG 1277, a galaxy 220 million light years away in the constellation Perseus.
That makes this the largest black hole we've seen so far, breaking the previous record
of 9.7 billion solar masses in NGC 3847. There's still a chance though that the one in NGC
4889 could be larger than this, but that hasn't been confirmed yet.
So worst case is this is the second biggest.
Here is what a black hole this big looks like. A 17 billion solar mass black hole would have
an event horizon that extends eleven times that of Neptune's orbit.
That's a radius of 4 light days.
(Space Fan trivia question: how big were the black holes in SFN 43?)
And how do they relate to this one?
Also, the more astute among you may have caught the fact that I said NGC 1277 was a lenticular
galaxy. Most galaxies with black holes this size are in ellipticals. Lenticular galaxies
are in between spirals and ellipticals, so they are younger and smaller.
Well, that's where this discovery really gets interesting. Remember I said most black holes
are generally 0.1 percent the mass of the galaxy they are in? Well this one is a whopping
14 percent.
This is the first time a black hole this big in relation to the host galaxy has been found
and has astronomers scratching their heads about whether what they think they know about
galaxy evolution is correct.
The galaxy is only ten percent the size and mass of our own Milky Way, but despite NGC
1277's small size, the black hole at its heart is more than 11 times as wide as Neptune's
orbit around the Sun.
Astronomers are saying this could be the first object in a new class of galaxy-black hole
systems.
I'll keep you posted.
Next, while we're on the subject of biggest things ever found, also this week, astronomers
using ESO’s Very Large Telescope (VLT) have discovered a quasar with the most energetic
outflow ever seen, at least five times more powerful than any that have been observed
to date.
Quasars are what comes out of black holes. They are these highly energetic jets of gamma
rays that are powered by the accretion disk of black holes. As matter falls in, it is
accelerated to energies that allow some of it to escape in these jets.
They are intensely bright and spew out huge amounts of material into their host galaxies.
This new study has looked at one of these objects — known as SDSS J1106+1939 — in
great detail, using the X-shooter instrument on ESO’s VLT at the Paranal Observatory
in Chile.
They found that the rate that energy is carried away by this huge mass of material ejected
at high speed is at least equivalent to two million million times the power output of
the Sun or about 100 times higher than the total power output of the entire Milky Way
galaxy.
For those who want more details, the outflow was measured to have a total a kinetic luminosity
of at least 10 to the 46 ergs per second.
And as my physics professor used to tell me, an erg is an ant pushup. Having 10 to the
46 ants, it would appear, is a pretty powerful thing.
Also, the outflow lies about a thousand light-years away from the supermassive black hole and
is at least five times more powerful than the previous record holder.
The team’s analysis shows that approximately a mass of 400 times that of the Sun is streaming
away from this quasar every year, moving at a speed of 8000 kilometres per second.
All of that makes this the most powerful quasar found so far.
Now this relates to my previous story because remember I said that with the discovery this
week of that huge black hole, well there is now some confusion over how the central black
hole in a galaxy relates to its mass.
Finding outflows this powerful may explain some of that. Perhaps most black holes are
spewing out more energy than we think, making them smaller, while the one in NCG 1277 is
not.
This may also explain why there are so few large galaxies in the universe.
So while one discovery raises questions and concerns, the other one may help explain them.
See how science works?
Well, that's it for this week Space Fans, thank you for watching and as always, Keep
Looking Up!