Astronomers pierce galactic clouds to shine light on black hole development

Jun 19, 2014
This is an illustration of the physical, spatial and temporal picture for the outflows emanating from the vicinity of the super massive black hole in the galaxy NGC 5548. The behavior of the emission source in five epochs is shown along the time axis. The obscurer is situated at roughly 0.03 light years (0.01 parsecs) from the emission source and is only seen in 2011 and 2013 (it is much stronger in 2013). Outflow component 1 shows the most dramatic changes in its absorption troughs. Different observed ionic species are represented as colored zones within the absorbers. Credit: Ann Feild/Space Telescope Science Institute

An international team of scientists including a Virginia Tech physicist have discovered that winds blowing from a supermassive black hole in a nearby galaxy work to obscure observations and x-rays.

The discovery in today's (June 19, 2004) issue of Science Express sheds light on the unexpected behavior of black holes, which emit large amounts of matter through powerful, galactic winds.

Using a large array of satellites and observatories, the team spent more than a year training their instruments on the brightest and most studied of the "local" black holes—the one situated at the core of Type I Seyfert Galaxy NGC 5548.

What they found was a bit of a surprise.

The researchers discovered much colder gas than expected based on past observations, showing that the wind had cooled and that a stream of gas moved quickly outward and blocked 90 percent of x-rays. The observation was the first direct evidence of an obscuration process that—in more luminous galaxies—has been shown to regulate growth of .

By looking at data from different sources, scientists found that a thick layer of gas lay between the galactic nucleus and the Earth blocked the lower energy x-rays often used to study the system, but allowed more energetic x-rays to get through.

This video is not supported by your browser at this time.
An animated journey through the active galaxy NGC 5548. For a more in-depth explanation of the video, please see the Supporting Online Material. Credit: Kaastra et al., Science/

Data from Hubble Space Telescope also showed ultraviolet emissions being partially absorbed by a stream of gas.

A multi-wavelength observational campaign simultaneously looking at an object to decipher its secrets is rare, the researchers said.

In this illustration, the position of a dark, absorbing cloud of material is located high above the supermassive black hole and accretion disk in the center of the active galaxy NGC 5548. Numerous other filaments twist around the black hole as they are swept away by a torrent of radiation "winds." Credit: NASA, ESA, and A. Feild (STScI)

"I don't think anyone has trained so many scopes and put in so much time on a single object like this," said Nahum Arav, an associate professor of physics with Virginia Tech's College of Science. "The result is quite spectacular. We saw something that was never studied well before and we also deciphered the outflow in the object. We know far more about this outflow than any studied previously as to where it is and how it behaves in time. We have a physical model that explains all the data we've taken of the outflow over 16 years."

This image depicts the galaxy NGC 5548 taken at the MDM Observatory 1.3m telescope. Credit: Dr. Misty Bentz

The discovery was made by an international team led by SRON Netherlands Institute for Space Research scientist Jelle Kaastra using the major space observatories of the European Space Agency, NASA, the Hubble Space Telescope, Swift, NuSTAR, Chandra, INTREGRAL, and other satellites and observation platforms.

"These outflows are thought to be a major player in the structure formation of the universe," Arav said "This particular outflow is comparatively small but because it's so close we can study it very well and then create a better understanding of how the phenomenon will work in very large objects that do affect the structure formation in the universe."

"Shadowing" of light from a black hole had not been seen before. With the discovery, scientists were able to decipher the outflow.

This is a cartoon of the central region of NGC 5548 (not to scale). The disk around the black hole (BH) emits X-ray, UV, optical and IR continuum and is surrounded by a dusty torus. The curved lines indicate the outflow of gas along the magnetic field lines of an accretion disk wind. The obscurer consists of a mixture of ionized gas with embedded colder, denser parts and is close to the inner UV broad emission line region (BLR). The narrow line region (NLR) and the persistent warm absorber (WA) are farther out. Credit: SRON

"Until now our knowledge of these characteristics was very limited," Arav said. "Before we were making educated inferences—but now we know. We know the distance of outflow from the center of source, we know the mass of outflow, and we know what causes its observed changes. The shadowing was definitely a surprise —a beautiful phenomenon we were lucky to catch."

Arav said luck played a part because the effect hadn't existed before last year.

Over the past two years the shadowing has built up and Arav believes it won't last much longer than another year or two, but concedes scientists don't have a full enough observation to say how the shadowing feature is changing in time.

Explore further: Chandra captures galaxy sparkling in X-rays

More information: "A fast and long-lived outflow from the supermassive black hole in NGC 5548," by J.S. Kaastra et al. Science Express, 2014. www.sciencemag.org/lookup/doi/… 1126/science.1253787

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User comments : 14

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MrPressure
Jun 19, 2014
This comment has been removed by a moderator.
joefe777
1 / 5 (10) Jun 19, 2014
I have found the Dark Matter: in the Head of Astronomers.
The NGC 5548 is NOT a Black Hole! They observing a Quasar...
Usually mixed the BH and the new born Stellar System in prephase too.
shavera
5 / 5 (7) Jun 19, 2014
I have found the Dark Matter: in the head of phys.org trolls.
The ZEPHYR is NOT a Black Hole! They are observing a Dense Aether Wave...
Usually mixed the EU and the new born Galactic Leyline in prephase too.
Tuxford
1 / 5 (4) Jun 19, 2014
Yes, outflows emanating from the grey hole are likely periodic. But so many galactic nuclei are observed with massive, massive outflows. Where does the matter come from if not born from within the core? Holmes would have no problem with this question, Watson.
JesusDeNazareth
5 / 5 (2) Jun 19, 2014
I'm kinda lost with all the trolls here. Hard to keep up. Can anyone sum it up for me?

I remember a creationist, Cantdance or something. Then this guy Zephyr, banned from everywhere, but don't know what he states. And don't remember the name of the plasma guy.
Bob Osaka
not rated yet Jun 19, 2014
Amazing stuff. To be able to notice changes over such a small time frame is absolutely incredible. I have nothing but superlatives to describe this work. Great job.
jsdarkdestruction
5 / 5 (7) Jun 19, 2014
I'm kinda lost with all the trolls here. Hard to keep up. Can anyone sum it up for me?

I remember a creationist, Cantdance or something. Then this guy Zephyr, banned from everywhere, but don't know what he states. And don't remember the name of the plasma guy.

hannesalvfen and yep and cantdrive are all plasma guys. I don't think cantdrive is a creationist but I could be wrong I guess.
verkle and freethinking are the creationists.
JesusDeNazareth
5 / 5 (1) Jun 19, 2014
Ah, that's right. I had them mixed up. Thanks.
cantdrive85
1 / 5 (5) Jun 20, 2014
What they found was a bit of a surprise.

What's not a surprise is that these astrophysicists are constantly surprised, so much for a theory which predicts anything whatsoever.

The result is quite spectacular. We saw something that was never studied well before and we also deciphered the outflow in the object.

At least they're honest about the dearth of research into electric currents in space, which is extremely odd considering magnetism is ubiquitous and must go hand in hand with electric currents. They still fail to make that connection here though, and fail to realize they're studying an electric current.

The shadowing was definitely a surprise

One of these days they'll understand the three modes of plasma, dark, glow, and arc.

I don't think cantdrive is a creationist

At least someone is paying attention. And you're correct, I don't believe in either of the two main creationist stories, the big bang or intelligent design...
MrPressure
Jun 20, 2014
This comment has been removed by a moderator.
alfie_null
5 / 5 (5) Jun 20, 2014
At least they're honest about the dearth of research into electric currents in space, which is extremely odd considering magnetism is ubiquitous and must go hand in hand with electric currents. They still fail to make that connection here though, and fail to realize they're studying an electric current.

Yeah, yeah. Everyone else is wrong and you, by your little lonely self are right. Sorry. All we can take from this is how utterly impervious self delusion can become in some people.

BTW, there was no mention of "electric currents in space" anywhere in the article. Not the same as admitting a "dearth of research". Nobody's looking into how much green cheese is in the Moon's crust either.
Protoplasmix
5 / 5 (4) Jun 20, 2014
Only real force is pushing force!
movement is always pushing force!

^ Look what an impoverished environment does to a developing human mind. This lad had no magnets to play with.

Contrast that with the effect of an enriched environment:
The discovery was made … using the major space observatories of the European Space Agency, NASA, the Hubble Space Telescope, Swift, NuSTAR, Chandra, INTREGRAL, and other satellites and observation platforms.

We need to borrow more $ from the Fed and World Bank so we can pay the interest we owe them and have a little leftover for more instruments, like JWST, LISA, et al. [/lunacy]
cantdrive85
1 / 5 (5) Jun 20, 2014
BTW, there was no mention of "electric currents in space" anywhere in the article.


You have that right, and I did note that in my comment. It seems they went to great lengths to avoid stating the obvious, but they "inferred" electric currents repeatedly.

"These outflows are thought to be a major player in the structure formation of the universe," Arav said


a stream of gas moved quickly outward


Numerous other filaments twist around


swept away by a torrent of radiation "winds."


and finally...

the outflow of gas along the magnetic field lines


An "outflow" of a twisting ionized "gas" filament along magnetic field lines is an "electric current in space", this is a fact. The presence of magnetic fields indicates there are electric currents, this too must be a fact unless you are proposing magic. Not my fault your "utterly impervious self delusion" cannot see the obvious...
JesusDeNazareth
5 / 5 (3) Jun 20, 2014
Uncle Ira is my favorite.

The comments section is very interesting, but has a very wasted potential. The lack of avatars, notifications, etc. With some changes it could attract new readers.
joefe777
1 / 5 (2) Jun 22, 2014
So, how can You see Accretion Disc around a Black Hole? The Accretion Disc is a special character of a newborn Solar System! What U think as BH, that is the supermass Nucleus of the Star...
Tuxford
1 / 5 (1) Jun 26, 2014
"There are other galaxies with similar streams of gas flowing outward from the direction of its central black hole, but we've never before found evidence that the stream of gas changed its position as dramatically as this one has,"

'The discovery comes as a bit of a surprise. While there's nothing odd about "winds" of ionized gas flowing from black holes, the stream of gas is moving away from galaxy NGC 5548 at speeds of up to 5,000 kilometers per second (11 million miles per hour). That's way faster than the galaxy's "persistent" wind, which blows at about 1,000 kilometers a second.'

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