Primordial black holes = dark matter ?

[FordGT90Concept]

Originally Posted by Inceptor

As I understand it, if Sagittarius A* is offset slightly, but still within the small 'region' of the black hole at galactic center (as it would have to be in order for stars to appear to be orbiting it and the black hole), there is no way to know what it is without a clever astrophysicist coming up with clever mathematical inferences, based upon observations, that they would be willing to publish.

It gushes out x-rays which is what a fission star would do and Hawking theorized black holes would as well.

[qubit]

Originally Posted by Drone

http://cdn.physorg.com/newman/gfx/ne...saschandra.jpg

Contrary to the popular perception of black holes pulling in all of the material that gets close, 95% of the matter in the disk around IGR J17091 is expelled by the wind. And other interesting fact is production of winds can stifle radio jets.



They said this because jet from the black hole was not present when the ultra-fast wind was seen, although a radio jet is seen at other times. Fascinating!

http://www.physorg.com/news/2012-02-...lack-hole.html

Indeed, this is really fascinating. I happened to read the same article over at TG Daily just before seeing your post.

I just wish I could overclock my PC to 20 million mph!

[Drone]

Two teams of astronomers have used data from NASA's Chandra X-ray Observatory and other telescopes to map the distribution of dark matter in a galaxy cluster known as Abell 383, which is located about 2.3 billion light years from Earth. Not only were the researchers able to find where the dark matter lies in the two dimensions across the sky, they were also able to determine how the dark matter is distributed along the line of sight

Interesting discovery

http://www.physorg.com/news/2012-03-...ll-galaxy.html

[Drone]

An international team of scientists have discovered an ‘ordinary’ black hole in the 12 million light year-distant galaxy Centaurus A. This is the first time that a normal-size black hole has been detected away from the immediate vicinity of our own Galaxy.

Fascinating!

The lowest-mass black holes are formed when very massive stars reach the end of their lives, ejecting most of their material into space in a supernova explosion and leaving behind a compact core that collapses into a black hole. There are thought to be millions of these low-mass black holes distributed throughout every galaxy.

But it's really hard to detect black holes because they don't emit light but when matter is dragged into a black hole it heats up in the process and emits X-Rays.

The team used the orbiting Chandra X-ray observatory to make six 100,000-second long exposures of Centaurus A, detecting an object with 50,000 times the X-ray brightness of our Sun. A month later, it had dimmed by more than a factor of 10 and then later by a factor of more than 100, so became undetectable. This behaviour is characteristic of a low mass black hole in a binary system during the final stages of an outburst and is typical of similar black holes in the Milky Way. It implies that the team made the first detection of a normal black hole so far away, for the first time opening up the opportunity to characterise the black hole population of other galaxies.

The yellow arrow identifies the position of the black hole transient inside Centaurus A. The location of the object is coincident with gigantic dust lanes that obscure visible and X-ray light from large regions of Centaurus A. Other interesting X-ray features include the central active nucleus, a powerful jet and a large lobe that covers most of the lower-right of the image. There is also a lot of hot gas. In the image, red indicates low energy, green represents medium energy, and blue represents high energy light.

http://www.physorg.com/news/2012-03-...ion-years.html

[qubit]

Keep the black hole stuff coming, this was fascinating!

12 million light years? OMG OMG - that's practically next door.

We're doomed - Doomed I say - Ahhhhhhhh!!!!

[m1dg3t]

Bring on the physics! I'm an idiot but this still interest's me

[Drone]

Another great discovery:

The newly discovered galaxy cluster is called the Musket Ball Cluster (located about 5.2 billion light years away from Earth). It is similar to the Bullet Cluster, the first system in which the separation of dark and normal matter was observed. However, this newly discovered system is older and slower than the Bullet Cluster.

You can spot a lot of galaxies there and intergalactic gas. Optical emission reveals the presence of dark matter through the effect of gravitational lensing (blue).

http://phys.org/news/2012-04-discove...l-cluster.html

[Drone]

Another black hole activity

An optical-IR image showing a galaxy that suddenly brightened when the supermassive black hole at its center shredded and absorbed a star that wandered too close.

Rest in pieces unlucky star ...

In May of 2010 Pan-STARRS telescope spotted what appeared to be a flare from a previously inactive, Milky-Way-sized supermassive black hole in a galaxy about two billion light-years away. Detailed modeling of the light led the team of astronomers to conclude that the black hole is about two million solar masses, and that the object it devoured was probably an evolved star (about 5 billion years old) whose mass was about 0.2 solar masses.

http://phys.org/news/2012-05-black-hole-flare.html

[qubit]

Wow, that's quite some brightening there. I'd love to be able to see a proper image of this thing up close as it happens. It would be fascinating. Interestingly, it's not just a tiny spec of a dot, but has an actual size and the other stars look bigger - our telescopes are getting better.

Drone, keep these posts coming!

[Drone]

bump time

Astronomers have found strong evidence that a massive black hole is being ejected from its host galaxy (CID-42) at a speed of several million miles per hour. New observations from NASA's Chandra X-ray Observatory suggest that the black hole collided and merged with another black hole and received a powerful recoil kick from gravitational wave radiation.

Gravitational wave recoil ... now that's what I call force!

"It's hard to believe that a supermassive black hole weighing millions of times the mass of the sun could be moved at all, let alone kicked out of a galaxy at enormous speed," said Francesca Civano of the Harvard-Smithsonian Center for Astrophysics, who led the new study. "But these new data support the idea that gravitational waves - ripples in the fabric of space first predicted by Albert Einstein but never detected directly - can exert an extremely powerful force."

Look at the speed of that thing ....

More optical data from the ground-based Magellan and Very Large Telescopes in Chile supplied a spectrum that suggested the two sources in CID-42 are moving apart at a speed of at least 3 million miles per hour.

http://phys.org/news/2012-06-giant-b...me-galaxy.html

[Drone]

Gas cloud will collide with our galaxy's black hole [known as Sagittarius A* (or Sgr A*)] in 2013. Go, check your calendars. This is the first time ever.

Scientists have determined a giant gas cloud is on a collision course with the black hole in the center of our galaxy, and the two will be close enough by mid-2013 to provide a unique opportunity to observe how a super massive black hole sucks in material, in real time. This will give astronomers more information on how matter behaves near a black hole.

Yeah it seems our galaxy doesn't like guests lol. That gas cloud is doomed, its days are numbered.
That's how Sgr A* welcomes guests.

By June of 2012, the gas cloud is expected to be just 36 light-hours (equivalent to 40,000,000,000 km) away from our galaxy's black hole, which is extremely close in astronomical terms. Astronomers have determined the speed of the gas cloud has increased, doubling over the past seven years, and is now reaching more than 8 million km/h. The cloud is estimated to be three times the mass of Earth and the density of the cloud is much higher than that of the hot gas surrounding black hole.

Can't wait to see that!

No one really knows how the collision will unfold, but the cloud's edges have already started to shred and it is expected to break up completely over the coming months. As the time of actual collision approaches, the cloud is expected to get much hotter and will probably start to emit X-rays as a result of the interaction with the black hole.

http://phys.org/news/2012-06-gas-clo...axy-black.html

[D007]

Seems to me common sense dictates, once u get enough mass you wouldn't need an explosion. Just a coalescing of that mass, until it becomes so large it is a blackhole.. Idk why you would need some kind of massive explosion.. Typical science jumping to conclusions...lol..

[Drone]

What explosion you're talking about? Supernovae?
In a nutshell: When a star reaches the end of its life it runs out of Hydrogen or other fuel. When this happens the balance (between heat pressure and gravity pull) gets broken. Outer region gets blown off, core region contracts. That's how "BOOM" happens.

See the links below:

http://planetfacts.org/supernova/
http://imagine.gsfc.nasa.gov/docs/sc...upernovae.html

[D007]

Originally Posted by Drone

bump time

http://cdn.physorg.com/newman/gfx/ne...antblackho.jpg



Gravitational wave recoil ... now that's what I call force!



Look at the speed of that thing ....



http://phys.org/news/2012-06-giant-b...me-galaxy.html

only 3 million mph? Meh I can do that on a moped..

[Drone]

A bunch of black holes has been found! Scientists were using the technique VLBI [Very Long Baseline Interferometry]. Their team made measurements at different radio wavelengths over a period of 17 years.

Astronomers have found evidence of hundreds of black holes in the centre of Arp 220 (a galaxy 250 million light years away). The discovery, made with a worldwide network of radio telescopes, gives scientists a new way to find out how black holes are created.

It's obvious: jets created by black holes are sending out radio signals.

Jets from black holes are visible at this distance only if they are pointing right towards us. Probably there are many more systems like this in this galaxy, but their jets point in other directions.

Jets blow the cover.

“We believe we are seeing radio emission from binary star systems in which one star has already exploded and left behind a black hole. The black hole “eats” gas which it draws from its companion, producing powerful jets that emit radio waves”, says Fabien Batejat, astronomer @ Chalmers, who led the study.

What a leecher! Suckah!

The galaxy Arp 220 is already famous for creating new stars at a furious pace. Previous research by the same team has also demonstrated that there are many supernova explosions in the galaxy, up to 250 times more than in our galaxy. Supernovae and black holes are related. Astronomers believe that black holes are created when stars with masses more than about 20 times the sun explode.

This discovery in Arp 220 gives astronomers hope to soon be able to put this idea to the test. Only a dozen black holes of this type are known in the Milky Way, and only a few are known in other galaxies.

That galaxy is pretty busy. Stars, supernovae, binary systems, rare types of black holes (microblazars).

These objects, known to astronomers as microblazars, were theoretically predicted over a decade ago. Astronomers believe microblazars are scaled-down versions of the cosmic beacons known as blazars. In a blazar, a supermassive black hole feasting on dense gas at the centre of a galaxy creates powerful jets which can be observed from Earth if they are directed towards us.

It seems that galaxies like Arp 220 can contain very large numbers of microblazars.

http://phys.org/news/2012-07-galaxy-...ack-holes.html

[qubit]

I thought I was interested in black holes, but damn Drone, you're heavily into them.

Great find. Hundreds of black holes, Jesus H f* Christ...

[Drone]

Hah, thanks qubit. Black holes are very interesting objects. There are so many theories about them.
One of them says that every black hole contains another universe

http://phys.org/news/2012-05-black-h...-solution.html
http://www.foxnews.com/scitech/2012/...-new-universe/

[Drone]

Newly found black hole.

Galaxy ESO 243-49, about 300 million light-years away, is home to the newly found black hole called HLX-1

This is the first discovered intermediate mass black hole. It was discovered by accident and they have no clue how it has come to exist.

HLX-1 has been described as being discovered almost by accident, as the research team at the time was instead focused on its host spiral galaxy. Black holes are generally more likely to sit at the center of galaxies such as the one that is believed to exist at the center of our own Milky Way. But HLX-1 was found, uncharacteristically, out in the spiral. It came to notice only because it was spewing a lot of x-rays and radio flares.

Peekaboo, I see you. It's about 90000 times heavier than our sun or something like that.

http://phys.org/news/2012-07-evidenc...lack-hole.html

[Inceptor]

I thought this was probably better off in this thread, rather than a new one:

A group of physicists and biologists are planning a DNA-based dark matter detector.
The plan is to detect the 'dark matter headwind' coming from the direction of the constellation of Cygnus (that is the direction that the Sun is travelling in, in its orbit around the galactic center).

Posting from the MIT Tech review from the Physics arxiv blog

[Drone]

Crazy stuff!

Using observations from telescopes in space and on the ground, astronomers gathered the most direct evidence yet for this violent process: a supermassive black hole shredding a star that wandered too close.

That suckah is a killah!

The galaxy where the supermassive black hole ripped apart the passing star in known as PS1-10jh and is located about 2.7 billion light years from Earth. Astronomers estimate the black hole in PS1-10jh has a mass of several million suns, which is comparable to the supermassive black hole in our own galaxy.

http://phys.org/news/2012-07-image-b...t-stellar.html

[m1dg3t]

Cheers Drone! Still trying to wrap mah head around all of this but keep 'em comming!

[Drone]

Here's a beautiful animation showing the awakening of a distant galaxy's dormant black hole as it shredded and gobbled up a passing star. The galaxy is so far away that light from the event had to travel 3.9 billion years before reaching Earth. So far, so violent, so beautiful *drools*

The star experienced intense tides as it reached its closest point to the black hole and was quickly torn apart. Some of its gas fell toward the black hole and formed a disk around it. The innermost part of this disk was rapidly heated to temperatures of millions of degrees, hot enough to emit X-rays. At the same time, through processes still not fully understood, oppositely directed jets perpendicular to the disk formed near the black hole. These jets blasted matter outward at velocities greater than 90 percent the speed of light along the black hole's spin axis. One of these jets just happened to point straight at Earth.

That's a sexy X-Ray shower there.

As hot gas in the innermost disk spirals toward a black hole, it reaches a point astronomers refer to as the innermost stable circular orbit (ISCO). Any closer to the black hole and gas rapidly plunges into the event horizon, the point of no return. The inward spiraling gas tends to pile up around the ISCO, where it becomes tremendously heated and radiates a flood of X-rays. The brightness of these X-rays varies in a pattern that repeats at a nearly regular interval, creating the QPO (quasi-periodic oscillation) signal.

Mesmerizing process. These QPOs send us information from the very brim of the black hole, which is where the effects of relativity become most extreme.



http://phys.org/news/2012-08-star-he...elativity.html

[Drone]

WISE (Wide-field Infrared Survey Explorer) identified about 2.5 million actively feeding supermassive black holes across the full sky, stretching back to distances more than 10 billion light-years away.

Umm ... can you imagine that?



Now that's a lot of them!

http://phys.org/news/2012-08-wise-su...ons-black.html

WISE scanned the whole sky twice in infrared light, completing its survey in early 2011. And that's not all... Astronomers have identified about 1000 hot DOGs (dust-obscured galaxies). That's one of the main goals of their mission.

Hot DOGs are powerful and brightest galaxies, they can pour out more than 100 trillion times as much light as our sun. They are so dusty, however, that they appear only in the longest wavelengths of infrared light captured by WISE.

That darn cosmic dust *shakes fist* ... but anyway this all is so amazing incredible and unbelievable.

[qubit]

Drone, this is especially for you.

The Strangest Black Holes in the Universe

So, just how immense is the gravity of the first black hole with an event horizon five times the size of the orbit of Pluto! I can't even begin to comprehend it.