Best view yet of dusty cloud passing galactic center black hole

March 26, 2015
This composite image shows the motion of the dusty cloud G2 as it closes in on, and then passes, the supermassive black hole at the centre of the Milky Way.These new observations with ESO's VLT have shown that the cloud appears to have survived its close encounter with the black hole and remains a compact object that is not significantly extended.In this image the position of the cloud in the years 2006, 2010, 2012 and February and September 2014 are shown, from left to right. The blobs have been colorized to show the motion of the cloud, red indicated that the object is receding and blue approaching. The cross marks the position of the supermassive black hole. Credit: ESO/A. Eckart

The best observations so far of the dusty gas cloud G2 confirm that it made its closest approach to the supermassive black hole at the centre of the Milky Way in May 2014 and has survived the experience. The new result from ESO's Very Large Telescope shows that the object appears not to have been significantly stretched. It is most likely to be a young star with a massive core that is still accreting material.

A supermassive black hole with a mass four million times that of the Sun lies at the heart of the Milky Way galaxy. It is orbited by a small group of bright stars and, in addition, an enigmatic dusty cloud, known as G2, has been tracked on its fall towards the black hole over the last few years. Closest approach, known as peribothron, was predicted to be in May 2014.

The great tidal forces in this region of very strong gravity were expected to tear the cloud apart and disperse it along its orbit. Some of this material would feed the black hole and lead to sudden flaring and other evidence of the monster enjoying a rare meal. To study these unique events, the region at the galactic centre has been very carefully observed over the last few years by many teams using large telescopes around the world.

A team led by Andreas Eckart (University of Cologne, Germany) has observed the region using ESO's Very Large Telescope (VLT) over many years, including new observations during the critical period from February to September 2014, just before and after the peribothron event in May 2014. These new observations are consistent with earlier ones made using the Keck Telescope on Hawaii .

The images of infrared light coming from glowing hydrogen show that the cloud was compact both before and after its , as it swung around the black hole.

As well as providing very sharp images, the SINFONI instrument on the VLT also splits the light into its component infrared colours and hence allows the velocity of the cloud to be estimated. Before closest approach, the cloud was found to be travelling away from the Earth at about ten million kilometres/hour and, after swinging around the black hole, it was measured to be approaching the Earth at about twelve million kilometres/hour.

Florian Peissker, a PhD student at the University of Cologne in Germany, who did much of the observing, says: "Being at the telescope and seeing the data arriving in real time was a fascinating experience," and Monica Valencia-S., a post-doctoral researcher also at the University of Cologne, who then worked on the challenging data processing adds: "It was amazing to see that the glow from the dusty cloud stayed compact before and after the close approach to the black hole."

Although earlier observations had suggested that the G2 object was being stretched, the new observations did not show evidence that the cloud had become significantly smeared out, either by becoming visibly extended, or by showing a larger spread of velocities.

In addition to the observations with the SINFONI instrument the team has also made a long series of measurements of the polarisation of the light coming from the region using the NACO instrument on the VLT. These, the best such observations so far, reveal that the behaviour of the material being accreted onto the black hole is very stable, and—so far—has not been disrupted by the arrival of material from the G2cloud.

The resilience of the dusty cloud to the extreme gravitational tidal effects so close to the black hole strongly suggest that it surrounds a dense object with a massive core, rather than being a free-floating cloud. This is also supported by the lack, so far, of evidence that the central monster is being fed with material, which would lead to flaring and increased activity.

Andreas Eckart sums up the new results: "We looked at all the recent data and in particular the period in 2014 when the closest approach to the black hole took place. We cannot confirm any significant stretching of the source. It certainly does not behave like a coreless dust cloud. We think it must be a dust-shrouded young star."

Explore further: VLT watches in real time as gas cloud makes closest approach to the monster at the centre of the Milky Way

More information: This research was presented in a paper "Monitoring the Dusty S-Cluster Object (DSO/G2) on its Orbit towards the Galactic Center Black Hole" by M. Valencia-S. et al. in the journal Astrophysical Journal Letters. www.eso.org/public/archives/re … eso1512/eso1512a.pdf

Related Stories

Could the Milky Way become a quasar?

February 27, 2015

A quasar is what you get when a supermassive black hole is actively feeding on material at the core of a galaxy. The region around the black hole gets really hot and blasts out radiation that we can see billions of light-years ...

Recommended for you

Solar minimum surprisingly constant

November 17, 2017

Using more than a half-century of observations, Japanese astronomers have discovered that the microwaves coming from the sun at the minimums of the past five solar cycles have been the same each time, despite large differences ...

SpaceX poised to launch secretive Zuma mission

November 16, 2017

SpaceX is poised to launch on Thursday a secretive payload known as Zuma for the US government, though the nature of the mission and the agency behind it remain a mystery.

10 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

britton_beckham
1 / 5 (14) Mar 26, 2015
I see the black hole! oh wait no I don't. Where's the "supposed" gravitation lensing?? No where, that's where. In fact, no images ever of the supposed black hole at the center of our galaxy have gravitational lensing visible. Looks like Einy was wrong :(
Gigel
4.4 / 5 (8) Mar 26, 2015
Gravitation lensing may have a much larger focal distance than the size of a galaxy, that's why it can be seen only on galaxies far away.
ursiny33
1 / 5 (5) Mar 26, 2015
Its not a theoretical black hole ,but a compacted dark matter mass with an orbiting particle plasma field ,made of the charged particles of atoms that were taken apart in this environment, any gas atoms interfacing with the orbiting particle field ,were stripped of their orbiting electrons and came apart, with charged particles joining the plasma field and the dark matter foundational particles that held the construction of those charged particles in an atom ,those joined the dark matter mass
ViperSRT3g
4.7 / 5 (3) Mar 26, 2015
Gravitational lensing does not amplify the brightness of distant objects enough to compete with objects that are in our cosmological backyard.

It's why gravitational lenses can be seen in distant galactic neighborhoods, while not being visible from nearby gravitational sources. Everything being viewed is of a similar low apparent brightness.

Gravitational lenses also require a high enough gravity threshold. For instance, our sun cannot bend light around itself so that you can see the things directly behind it. Yet a black hole can bend light enough where you can see the light of an object immediately behind it.
big_hairy_jimbo
5 / 5 (1) Mar 26, 2015
@ViperSRT3g, I thought Relativity was tested using that very scenario of seeing a star behind the sun, during an eclipse??
Steve 200mph Cruiz
5 / 5 (6) Mar 27, 2015
Britton,
You see the picture? There's a red cross, that's the black hole. That blob is a time lapse picture of a gas cloud. It changes from yellow to red to deep blue. That means it was moving away from us, got pulled away faster, then got flung twards us.

They can calculate it's trajectory from that information, and its trajectory agrees with Einstein.
Dethe
1 / 5 (5) Mar 27, 2015
The central "black hole" of Milky Way behaves strangely according to mainstream theories, as it doesn't interact with clouds of interstellar gas, it even doesn't exhibit gravitational lensing. It behaves merely as a barycenter of Milky Way. Compare also study of M85 and another galaxies with alleged black holes, where their black hole effect are missing.
Dethe
1 / 5 (2) Mar 27, 2015
Ewill2007
not rated yet Mar 27, 2015
I have a question.

I remember a documentary last year predicting that g2 would be swallowed by the black hole.

And now it goes past again and the black hole has not swallowed it.

So my question is giving the size of our black hole to our galaxy which is 4 million solar masses, a dwarf galaxy not far away has a black hole 4 billion solar masses. Is it possible this is not a black hole? Maybe an ECO?

My second question is their evidence of any black hole eating anything in the known universe to date?
Tuxford
1 / 5 (1) Mar 30, 2015
It certainly does not behave like a coreless dust cloud. We think it must be a dust-shrouded young star."


Exactly what LaViolette predicted before the passing began. That it was a star expelling gas, since it is in the vicinity of extreme mass. Being in this region accelerates the production of new matter there-inside the star's core, causing an expulsion of excess matter, creating the cloud.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.