Space

August 31, 2013

NASA’s Chandra Observatory catches giant black hole rejecting material

nasa-chandra
 

Astronomers using NASA’s Chandra X-ray Observatory have taken a major step in explaining why material around the giant black hole at the center of the Milky Way Galaxy is extraordinarily faint in X-rays. This discovery holds important implications for understanding black holes.

New Chandra images of Sagittarius A* (Sgr A*), which is located about 26,000 light-years from Earth, indicate that less than 1 percent of the gas initially within Sgr A*’s gravitational grasp ever reaches the point of no return, also called the event horizon. Instead, much of the gas is ejected before it gets near the event horizon and has a chance to brighten, leading to feeble X-ray emissions.

These new findings are the result of one of the longest observation campaigns ever performed with Chandra. The spacecraft collected five weeks’ worth of data on Sgr A* in 2012. The researchers used this observation period to capture unusually detailed and sensitive X-ray images and energy signatures of super-heated gas swirling around Sgr A*, whose mass is about 4 million times that of the sun.

“We think most large galaxies have a supermassive black hole at their center, but they are too far away for us to study how matter flows near it,” said Q. Daniel Wang of the University of Massachusetts in Amherst, who led of a study published Thursday in the journal Science. “Sgr A* is one of very few black holes close enough for us to actually witness this process.”

The researchers found that the Chandra data from Sgr A* did not support theoretical models in which the X-rays are emitted from a concentration of smaller stars around the black hole. Instead, the X-ray data show the gas near the black hole likely originates from winds produced by a disk-shaped distribution of young massive stars.

“This new Chandra image is one of the coolest I’ve ever seen,” said co-author Sera Markoff of the University of Amsterdam in the Netherlands. “We’re watching Sgr A* capture hot gas ejected by nearby stars, and funnel it in towards its event horizon.”

To plunge over the event horizon, material captured by a black hole must lose heat and momentum. The ejection of matter allows this to occur.

“Most of the gas must be thrown out so that a small amount can reach the black hole”, said Feng Yuan of Shanghai Astronomical Observatory in China, the study’s co-author. “Contrary to what some people think, black holes do not actually devour everything that’s pulled towards them. Sgr A* is apparently finding much of its food hard to swallow.”

The gas available to Sgr A* is very diffuse and super-hot, so it is hard for the black hole to capture and swallow it. The gluttonous black holes that power quasars and produce huge amounts of radiation have gas reservoirs much cooler and denser than that of Sgr A*.

The event horizon of Sgr A* casts a shadow against the glowing matter surrounding the black hole. This research could aid efforts using radio telescopes to observe and understand the shadow. It also will be useful for understanding the effect orbiting stars and gas clouds may have on matter flowing toward and away from the black hole.

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.

The paper is available online at http://arxiv.org/abs/1307.5845.




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


 
 

 
NASA photograph by Dimitri Gerondidakis

NASA’s Orion spacecraft, rocket move closer to first flight

NASA photograph by Dimitri Gerondidakis The United Launch Alliance Delta IV Heavy rocket that will send NASA’s Orion spacecraft on its first flight test in December was moved to its vertical launch position Oct. 1 at Space La...
 
 
lm-orion3

Orion spacecraft transfers To launch abort system facility

https://www.youtube.com/watch?v=j68mszdhTmY NASA and Lockheed Martin have finished fueling the Orion spacecraft with ammonia, hydrazine and high pressure helium at Kennedy Space Center’s Payload Hazardous Servicing Facili...
 
 

NASA telescopes find clear skies, water vapor on exoplanet

Astronomers using data from three of NASA’s space telescopes – Hubble, Spitzer and Kepler – have discovered clear skies and steamy water vapor on a gaseous planet outside our solar system. The planet is about the size of Neptune, making it the smallest planet from which molecules of any kind have been detected. “This discovery...
 

 
NASA photograph by Aubrey Gemignani

New crew launches to space station to continue scientific research

NASA photgoraph Three crew members are heading to the International Space Station after launching in a Soyuz spacecraft from the Baikonur Cosmodrome in Kazakhstan at 4:25 p.m., EDT, Sept. 25. Three crew members representing the...
 
 

NASA expands commercial space program, requests proposals for IS resupply

On the heels of awarding groundbreaking contracts to U.S. commercial space companies to ferry American astronauts to the International Space Station, NASA has released a request for proposals for the next round of contracts for private-sector companies to deliver experiments and supplies to the orbiting laboratory. Under the Commercial Resupply Services 2 RFP, NASA intends...
 
 

ATK offers solid solution to U.S. Air Force’s RD-180 replacement request

ATK has provided the U.S. Air Force an American-made commercial solid rocket solution as a replacement for the RD-180 Russian-made, first-stage engine of United Launch Alliance’s Atlas V launch vehicle. “ATK’s solid rocket propulsion solution provides a cost-effective, reliable solution based on advanced technology,” said Blake Larson, president of ATK’s Aerospace ...
 




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=""> <strike> <strong>