Space

June 20, 2014

Swiftly moving gas streamer eclipses supermassive black hole

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.”

An international team of astronomers, using data from several NASA and European Space Agency space observatories, has discovered unexpected behavior from the supermassive black hole at the heart of the galaxy NGC 5548, located 244.6 million light-years from Earth.

This behavior may provide new insights into how supermassive black holes interact with their host galaxies.

Immediately after NASA’s Hubble Space Telescope observed NGC 5548 in June 2013, this international research team discovered unexpected features in the data. They detected a stream of gas flowing rapidly outward from the galaxy’s supermassive black hole, blocking 90 percent of its emitted X-rays.

“The data represented dramatic changes since the last observation with Hubble in 2011,” said Gerard Kriss of the Space Telescope Science Institute (STScI) in Baltimore, Maryland. “I saw signatures of much colder gas than was present before, indicating that the wind had cooled down due to a significant decrease in X-ray radiation from the galaxy’s nucleus.”

The discovery was made during an intensive observing campaign that also included data from NASA’s Swift spacecraft, Nuclear Spectroscopic Telescope Array (NuSTAR) and Chandra X-ray Observatory, as well as ESA’s X-ray Multi-Mirror Mission (XMM-Newton) and Integral gamma-ray observatory (INTEGRAL).

After combining and analyzing data from all six sources, the team was able to put together the pieces of the puzzle. Supermassive black holes in the nuclei of active galaxies, such as NGC 5548, expel large amounts of matter through powerful winds of ionized gas. For instance, the persistent wind of NGC 5548 reaches velocities exceeding 621 miles (approximately 1,000 kilometers) a second. But now a new wind has arisen, much stronger and faster than the persistent wind.

“These new winds reach speeds of up to 3,107 miles (5,000 kilometers) per second, but is much closer to the nucleus than the persistent wind,” said lead scientist Jelle Kaastra of the SRON Netherlands Institute for Space Research. “The new gas outflow blocks 90 percent of the low-energy X-rays that come from very close to the black hole, and it obscures up to a third of the region that emits the ultraviolet radiation at a few light-days distance from the black hole.”

The newly discovered gas stream in NGC 5548 — one of the best-studied of the type of galaxy know as Type I Seyfert — provides the first direct evidence of a shielding process that accelerates the powerful gas streams, or winds, to high speeds. These winds only occur if their starting point is shielded from X-rays.

It appears the shielding in NGC 5548 has been going on for at least three years, but just recently began crossing their line of sight.

“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,” said Kriss. “This is the first time we’ve seen a stream like this move into our line of sight. We got lucky.”

Researchers also deduced that in more luminous quasars, the winds may be strong enough to blow off gas that otherwise would have become “food” for the black hole, thereby regulating both the growth of the black hole and that of its host galaxy.

These results are being published online in the Thursday issue of Science Express.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. STScI conducts Hubble science operations and is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.




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


 
 

 

Headlines October 24, 2014

News: U.S., South Korea delay transfer of wartime control - The U.S. and South Korea have delayed transferring wartime operational control of allied forces by taking on a “conditions-based approach” and scrapping the previously set deadline of 2015.   Business: Exclusive: Lockheed, Pentagon reach $4 billion deal for more F-35 jets - Lockheed Martin and U.S. defense...
 
 

News Briefs October 24, 2014

French moving troops toward Libyan border A top French military official says the country is moving troops toward the Libyan border within weeks and, along with U.S. intelligence, is monitoring al Qaeda arms shipments to Africa’s Sahel region. A French base will go up within weeks in a desert outpost just a hundred kilometers (60...
 
 
Navy photograph

Navy to commission submarine North Dakota

Navy photograph The PCU North Dakota (SSN 784) during bravo sea trials. The crew performed exceptionally well on both alpha and bravo sea trials. The submarine North Dakota is the 11th ship of the Virginia class, the first U.S....
 

 

Boeing announces SF Airlines order for Boeing converted freighters

Boeing announced Oct. 23 that SF Airlines has placed an order for an undisclosed number of 767-300ER passenger-to-freighter conversions (Boeing Converted Freighters). SF Airlines, a subsidiary of Shenzhen, China-based delivery services company SF Express, will accept its first redelivered 767 in the second half of 2015. “SF Express aims to become China’s most respected and...
 
 
LM-C130

Another Super Herc Little Rock Rollin’

  Lockheed Martin delivered another C-130J Super Hercules to the 61st Airlift Squadron at Little Rock Air Force Base, Ark., Oct. 23. Little Rock AFB’s new C-130J was ferried from the Lockheed Martin Aeronautics facility ...
 
 

United Technologies beats third quarter profit expectations

United Technologies Corp. Oct. 23 reported third-quarter profit of $1.85 billion as sales increased across all its businesses and the aerospace giant reported favorable tax settlements. The Hartford, Conn.,-based company said it had profit of $2.04 per share and earnings, adjusted for non-recurring gains, came to $1.82 per share. The results topped Wall Street expectations,...
 




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>