Cidersomerset
31st May 2013, 14:20
http://static.bbci.co.uk/frameworks/barlesque/2.45.9/desktop/3.5/img/blq-blocks_grey_alpha.png
31 May 2013 Last updated at 10:04
Black hole bonanza possible as immense gas cloud passes
By Jason Palmer
Science and technology reporter, BBC News
http://news.bbcimg.co.uk/media/images/67889000/jpg/_67889191_67889190.jpg
Simulation of G2 cloud passing galactic centre The cloud will approach Sagittarius A* on
an elliptical orbit, passing close but not getting entirely sucked in A vast and hidden
field of small black holes predicted to be near the centre of our galaxy could be revealed
as a giant gas cloud passes by.The G2 cloud is as large as our Solar System, and bound
for a "supermassive" black hole at the Milky Way's core.On the way, it should encounter
many black holes just tens of km across.A report in Physical Review Letters suggests
they will spin and heat the gas, which will emit a spray of X-ray light that telescopes
could see.The cloud of gas - three times larger than Pluto's orbit but with a total mass
just three times that of the Earth - was first spotted on its course toward the galaxy's
centre in 2011. Researchers have been gearing up for the cloud's approach to the
galaxy's enormous central black hole, with its closest approach in September.
'Special opportunity'
But Imre Bartos of Columbia University in New York, US, and colleagues hit on the idea
of using the cloud's passage for another purpose.
"We know that there is a very massive black hole in the centre of the galaxy, many
millions of times heavier than our Sun, and we also suspect that there are thousands
and thousands much smaller - a few times the mass of the Sun," explained Dr Bartos.
Black Holes..
http://news.bbcimg.co.uk/media/images/64441000/jpg/_64441088_galex-20060823-browse.jpg
Could you survive falling into one?
"When I first saw this G2 cloud going toward the centre, we thought that this may be
the first opportunity to hopefully say something directly, to see these black holes near
the centre," he told BBC News.The idea is that as the cloud speeds past these small
black holes - some slightly more massive than our Sun but just a few tens of km across -
gas will spiral around them faster and faster, heating up to millions of degrees and
emitting X-ray light.It is a bit like allowing a giant sink to empty through thousands of
tiny drains and looking for any evidence of swirling water.The team estimates - based
on guesses about just how much gas is in the cloud - that as G2 makes its pass around
the central black hole, X-ray space telescopes such as Chandra or NuStar should be able
to glimpse about 16 interactions with its smaller cousins.
Keeping an eye out for these X-rays may also confirm the existence of what are
called "intermediate mass" black holes - a few thousand times the mass of our Sun.
Here again, theory predicts their existence - particularly near the centres of galaxies -
but none has ever been definitively confirmed.
"I think it's a good idea," said Stefan Gillessen of the Max Planck Institute for
Extraterrestrial Physics, co-author of the 2012 paper in Nature on the G2 cloud's
discovery.
"We didn't think of that when we did the original paper - I think it's something worth
following up," he told BBC News.
"But the big uncertainty, as always in this game, is what is the density of the gas which
comes in."
The less dense the gas is, the less likely that enough light will be produced that our
telescopes can see it. But as Dr Bartos points out, it is the first real chance to get a look
at what may be thousands of smaller black holes hidden between us and the galactic
core.
"It's a very special opportunity, and it's also lucky that we've now got the capacity to
observe these things with X-ray telescopes on satellites," he said.
http://news.bbcimg.co.uk/media/images/67889000/jpg/_67889194_67889192.jpg
Observations showing G2 cloud movement The cloud was spotted in 2011, moving at
speeds of millions of m/s
http://www.bbc.co.uk/news/science-environment-22694229
31 May 2013 Last updated at 10:04
Black hole bonanza possible as immense gas cloud passes
By Jason Palmer
Science and technology reporter, BBC News
http://news.bbcimg.co.uk/media/images/67889000/jpg/_67889191_67889190.jpg
Simulation of G2 cloud passing galactic centre The cloud will approach Sagittarius A* on
an elliptical orbit, passing close but not getting entirely sucked in A vast and hidden
field of small black holes predicted to be near the centre of our galaxy could be revealed
as a giant gas cloud passes by.The G2 cloud is as large as our Solar System, and bound
for a "supermassive" black hole at the Milky Way's core.On the way, it should encounter
many black holes just tens of km across.A report in Physical Review Letters suggests
they will spin and heat the gas, which will emit a spray of X-ray light that telescopes
could see.The cloud of gas - three times larger than Pluto's orbit but with a total mass
just three times that of the Earth - was first spotted on its course toward the galaxy's
centre in 2011. Researchers have been gearing up for the cloud's approach to the
galaxy's enormous central black hole, with its closest approach in September.
'Special opportunity'
But Imre Bartos of Columbia University in New York, US, and colleagues hit on the idea
of using the cloud's passage for another purpose.
"We know that there is a very massive black hole in the centre of the galaxy, many
millions of times heavier than our Sun, and we also suspect that there are thousands
and thousands much smaller - a few times the mass of the Sun," explained Dr Bartos.
Black Holes..
http://news.bbcimg.co.uk/media/images/64441000/jpg/_64441088_galex-20060823-browse.jpg
Could you survive falling into one?
"When I first saw this G2 cloud going toward the centre, we thought that this may be
the first opportunity to hopefully say something directly, to see these black holes near
the centre," he told BBC News.The idea is that as the cloud speeds past these small
black holes - some slightly more massive than our Sun but just a few tens of km across -
gas will spiral around them faster and faster, heating up to millions of degrees and
emitting X-ray light.It is a bit like allowing a giant sink to empty through thousands of
tiny drains and looking for any evidence of swirling water.The team estimates - based
on guesses about just how much gas is in the cloud - that as G2 makes its pass around
the central black hole, X-ray space telescopes such as Chandra or NuStar should be able
to glimpse about 16 interactions with its smaller cousins.
Keeping an eye out for these X-rays may also confirm the existence of what are
called "intermediate mass" black holes - a few thousand times the mass of our Sun.
Here again, theory predicts their existence - particularly near the centres of galaxies -
but none has ever been definitively confirmed.
"I think it's a good idea," said Stefan Gillessen of the Max Planck Institute for
Extraterrestrial Physics, co-author of the 2012 paper in Nature on the G2 cloud's
discovery.
"We didn't think of that when we did the original paper - I think it's something worth
following up," he told BBC News.
"But the big uncertainty, as always in this game, is what is the density of the gas which
comes in."
The less dense the gas is, the less likely that enough light will be produced that our
telescopes can see it. But as Dr Bartos points out, it is the first real chance to get a look
at what may be thousands of smaller black holes hidden between us and the galactic
core.
"It's a very special opportunity, and it's also lucky that we've now got the capacity to
observe these things with X-ray telescopes on satellites," he said.
http://news.bbcimg.co.uk/media/images/67889000/jpg/_67889194_67889192.jpg
Observations showing G2 cloud movement The cloud was spotted in 2011, moving at
speeds of millions of m/s
http://www.bbc.co.uk/news/science-environment-22694229