Space

November 20, 2013

NASA’s Chandra helps confirm evidence of jet in Milky Way’s black hole

Astronomers have long sought strong evidence that Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, is producing a jet of high-energy particles. Finally they have found it, in new results from NASA’s Chandra X-ray Observatory and the National Science Foundation’s Very Large Array radio telescope.

Previous studies, using a variety of telescopes, suggested there was a jet, but these reports – including the orientation of the suspected jets – often contradicted each other and were not considered definitive.

“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 appearing in an upcoming edition of The Astrophysical Journal and available online now.

Jets of high-energy particles are found throughout the universe, on large and small scales. They are produced by young stars and by black holes a thousand times larger than the Milky Way’s black hole. They play important roles in transporting energy away from the central object and, on a galactic scale, in regulating the rate of formation of new stars.

“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.

Scientists think jets are produced when some material falling toward the black hole is redirected outward. Since Sgr A* is presently known to be consuming very little material, it is not surprising the jet appears weak. A jet in the opposite direction is not seen, possibly because of gas or dust blocking the line of sight from Earth or a lack of material to fuel the jet.

The region around Sgr A* is faint, which means the black hole has been quiet in the past few hundred years. However, a separate Chandra study announced last month shows that it was at least a million times brighter before then.

“We know this giant black hole has been much more active at consuming material in the past. When it stirs again, the jet may brighten dramatically,” said co-author Frederick K. Baganoff of the Massachusetts Institute of Technology in Cambridge, Mass.

Astronomers have suggested the giant bubbles of high-energy particles extending out from the Milky Way and detected by NASA’s Fermi Gamma Ray Telescope in 2008 are caused by jets from Sgr A* that are aligned with the rotation axis of the galaxy. The latest results from Chandra support this explanation.

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

NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra Program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

To read the paper describing these results, visit http://xxx.lanl.gov/abs/1310.0146.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines July 7, 2015

News: F-35 loses dogfight to fighter jet from 1980s – A new report alleges that an F-35A was defeated by the very aircraft it is meant to replace.   Business: South Korea selects Airbus for $1.33 billion tanker contract – European aerospace giant Airbus won a $1.33 billion deal June 30 to supply air refueling...
 
 
U.S. Chamber of Commerce photograph

Boeing, Embraer to collaborate on ecoDemonstrator technology tests

U.S. Chamber of Commerce photograph Frederico Curado, president & CEO of Embraer, and Marc Allen, president of Boeing International, at the Brazil-U.S. Business Summit in Washington, D.C. The event occurred during an offici...
 
 
Untitled-2

Tactical reconnaissance vehicle project eyes hoverbike for defense

The U.S. Army Research Laboratory, or ARL, has been exploring the tactical reconnaissance vehicle, or TRV, concept for nearly nine months and is evaluating the hoverbike technology as a way to get Soldiers away from ground thre...
 

 
Air Force photograph by SSgt. William Banton

Upgraded AWACS platform tested at Northern Edge

Air Force photograph by SSgt. William Banton Maintenance crew members prepare an E-3G Sentry (AWACS) for takeoff during exercise Northern Edge June 25, 2015. Roughly 6,000 airmen, soldiers, sailors, Marines and Coast Guardsmen ...
 
 
LM-Legion

Lockheed Martin’s Legion Pod™ takes to skies

Lockheed Martin photograph by Randy Crites Lockheed Martin’s Legion Pod recently completed its first flight test, successfully tracking multiple airborne targets while flying on an F-16 in Fort Worth, Texas. Legion Pod was in...
 
 
Air Force photograph by SSgt. Marleah Robertson

First Marine graduates Air Force’s F-35 intelligence course

Air Force photograph by SSgt. Marleah Robertson Marine Corps 1st Lt. Samuel Winsted, an F-35B Lightning II intelligence officer, provides a mock intelligence briefing to two instructors during the F-35 Intelligence Formal Train...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>