Best Evidence Yet for a High-Energy Jet Emanating from the Milky Way’s Black Hole

by Nancy Atkinson on November 20, 2013

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A composite image in X-ray and radio showing a likely candidate for a jet emanating from the supermassive black hole at the center of the Milky Way. X-ray: NASA/CXC/UCLA/Z.Li et al; Radio: NRAO/VLA

A composite image in X-ray and radio showing a likely candidate for a jet emanating from the supermassive black hole at the center of the Milky Way. X-ray: NASA/CXC/UCLA/Z.Li et al; Radio: NRAO/VLA

Jets of high energy particles emanating from a black hole have been detected plenty of times before, but in other galaxies, that is — not from the supermassive black hole at the center of the Milky Way, known as Sagittarius A* (Sgr A*). Previous studies and other evidence suggested that perhaps there were jets – or ghosts of past jets – but many findings and studies often contradicted each other, and none were considered definitive.

Now, astronomers using Chandra X-ray Observatory and the Very Large Array (VLA) radio telescope have found strong evidence Sgr A* is producing a jet of high-energy particles.

“For decades astronomers have looked for a jet associated with the Milky Way’s black hole. Our new observations make the strongest case yet for such a jet,” said Zhiyuan Li of Nanjing University in China, lead author of a study in The Astrophysical Journal.

The supermassive black hole at the center of the Milky Way is about four million times more massive than our Sun and lies about 26,000 light-years from Earth.

While the common notion is that black holes inhale and ingest everything that comes their way, that’s not always true. Sometimes they reject small portions of incoming mass, pushing it away in the form of a powerful jet, and many times a pair of jets. These jets also feed the surroundings, releasing both mass and energy and likely play important roles in regulating the rate of formation of new stars.

Sgr A* is presently known to be consuming very little material, and so the jet is weak, making it difficult to detect. Astronomers don’t see another jet “shooting” in the opposite direction but that may be because of gas or dust blocking the line of sight from Earth or a lack of material to fuel the jet. Or there may be just a single jet.

“We were very eager to find a jet from Sgr A* because it tells us the direction of the black hole’s spin axis. This gives us important clues about the growth history of the black hole,” said Mark Morris of the University of California at Los Angeles, a co-author of the study.

The study shows the spin axis of Sgr A* is pointing in one direction, parallel to the rotation axis of the Milky Way, which indicates to astronomers that gas and dust have migrated steadily into Sgr A* over the past 10 billion years. If the Milky Way had collided with large galaxies in the recent past and their central black holes had merged with Sgr A*, the jet could point in any direction.

The jet appears to be running into gas near Sgr A*, producing X-rays detected by Chandra and radio emission observed by the VLA. The two key pieces of evidence for the jet are a straight line of X-ray emitting gas that points toward Sgr A* and a shock front — similar to a sonic boom — seen in radio data, where the jet appears to be striking the gas. Additionally, the energy signature, or spectrum, in X-rays of Sgr A* resembles that of jets coming from supermassive black holes in other galaxies.

The Chandra observations in this study were taken between September 1999 and March 2011, with a total exposure of about 17 days.

Source: Chandra

About 

Nancy Atkinson is Universe Today's Senior Editor. She also is the host of the NASA Lunar Science Institute podcast and works with Astronomy Cast. Nancy is also a NASA/JPL Solar System Ambassador.

Gozlemci November 20, 2013 at 11:58 PM

“While the common notion is that black holes inhale and ingest everything
that comes their way, that’s not always true. Sometimes they reject small
portions of incoming mass, pushing it away in the form of a powerful jet, and
many times a pair of jets…”
We need to discuss this “new” finding…

While we say this, we need to explain the former “finding” that had been said: “Nobody could escape from a black hole…
Another question: Does a black hole work like a heart…?

More questions, later…

ren00r November 21, 2013 at 7:49 AM

the jet forms outside event horizon, i.e. outside “black hole”, so it never has to leave it. another question is too ambiguous to answer, but few things are certain, for example black hole doesn’t pump black blood to black lungs.

Prism2Spectrum November 22, 2013 at 9:20 AM

“[ Scientist ] group used the Chandra X-Ray Observatory to see how black holes can pump energy in a gentler and rhythmic fashion, rather than violently. These scientists say the powerful black holes at the center of massive galaxies act as hearts to the systems, pumping energy out at regular intervals to regulate the growth of the black holes themselves, as well as star formation. ‘Just like our hearts periodically pump our circulatory systems to keep us alive, black holes give galaxies a vital warm component. They are a careful creation of nature, allowing a galaxy to maintain a fragile equilibrium,’ said Alexis Finoguenov, of the Max-Planck Institute for Extraterrestrial Physics in Germany.”

– Nancy Akinson, “Black Holes Supply Lifeblood for Galaxies” ( 11.18.08 ).

http://chandra.harvard.edu/photo/2008/m84/m84_moviefast_sm_web.mov

Prism2Spectrum November 22, 2013 at 9:31 AM
Gozlemci November 21, 2013 at 10:01 AM

One more question:
Who (what energy source or means) pushes the jets away from the Black Hole…?

Mikethebike November 21, 2013 at 11:32 AM

As the jet is (maybe) streaming in one directiom then Newton’s law predicts a force in the
the oppositedirection. This means the black hole must (maybe) moving in the opposite direction to the stream. Does this mean the Milky Way is also moving? Comments please.

Aqua4U November 21, 2013 at 12:58 PM

Reminds.. Recent X-ray images of the Andromeda Galaxy apparently show several jets? http://www.chandra.harvard.edu/photo/2013/m31/

How might these newly discovered jets be related to the gamma ray halo’s detected at the Milky Way’s poles? https://www.google.com/#q=gamma+rays+in+the+Milky+Way%27s+halo

magnus.nyborg November 22, 2013 at 5:06 PM

There are mostly (perhaps always) 2 opposing jets that cancel out the effects. One of the jets might be obscured and not readily visible, but until there are good measured evidence for a single jet, the double jet scenario are more likely.

raomap November 29, 2013 at 12:25 AM

My comment is exclusively on ‘gas near Sgr A*, producing X-rays detected by Chandra and radio emission observed by the VLA’. There is a strong possibility that the X-rays detected could be characteristic X-rays from gaseous 235-Uranium fission products such as 133-Xe and 85-Kr. The paper published lately in 2013 provides insights how 133-Xe, 85-Kr etc provide Bharat Radiation emission in the range 12.87 to 31 nm, followed by Extreme UV, UV, visible, and near infrared radiations.

M.A. Padmanabha Rao,
Discovery of Self-Sustained 235-U Fission Causing Sunlight by Padmanabha Rao Effect,
IOSR Journal of Applied Physics (IOSR-JAP), Volume 4, Issue 2 (Jul. – Aug. 2013), PP 06-24, DOI: 10.9790/4861-0420624
http://www.iosrjournals.org/iosr-jap/papers/Vol4-issue2/B0420624.pdf

EXCERPTS OF THE PAPER: Sunlight phenomenon being one of the most complex phenomena in science evaded from previous researchers. Understanding the phenomenon needed advanced knowledge in the fields of nuclear physics, X-ray physics, and atomic spectroscopy. A surprise finding, optical emission detected from Rb XRF source in 1988 led to the discovery of a previously unknown atomic phenomenon causing Bharat radiation emission followed by optical emission from radioisotopes and XRF sources reported in 2010 [10]. The same phenomenon was found causing the Sunlight. However, it took nearly 25 years of research to reach the current level of understanding the Sunlight phenomenon reported here.

BREAKTHROUGHS:
(1) On the basis of fusion, many solar lines could not be identified previously and what causes these lines remained puzzling. Though 11 solar lines could be identified by other researchers, they became questionable. The significant breakthrough has come when it became possible now to identify as many as 153 lines on the basis of uranium fission taking place on Sun’s core surface. Surprisingly, the fission products released in Chernobyl reactor accident in 1986 also seem to be present in solar flares.

(2) Explained what are Sun’s dark spots and their cause.

(3) For the first time, it is shown what constitutes Dark Matter and showed existence of Dark Matter in Sun.

(4) It is explained with unprecedented detail how Bharat Radiation from fission products (radioisotopes) causes Sunlight by an atomic phenomenon known as Padmanabha Rao Effect.

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