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 November 24, 2014

News: Hagel said to be stepping down as defense chief under pressure - Defense Secretary Chuck Hagel is stepping down under pressure, the first cabinet-level casualty of President Obama’s Democratic majority in the Senate and a beleaguered national security team that has struggled to stay ahead of an onslaught of global crises. Afghan mission for U.S....
 
 

News Briefs November 24, 2014

Fog forces five U.S. choppers to land in Polish field Officials say that that fog forced five U.S. Army helicopters to make an emergency landing in a Polish field and spend the night there, the second such incident since September. The U.S. Army said 15 soldiers were moving equipment to their base in Germany Nov....
 
 
Air Force photograph by Samuel King Jr.

Navy’s first F-35C squadron surpasses 1,000 flight hours

Air Force photograph by Samuel King Jr. An F-35C Lightning II aircraft piloted by Lt. Cmdr. Chris Tabert, assigned to Strike Fighter Squadron (VFA) 101, flies the squadron’s first local sortie. The F-35C is the carrier va...
 

 
boeing-SC-787

Boeing South Carolina begins final assembly of its first 787-9 Dreamliner

Boeing has started final assembly of the 787-9 Dreamliner at its South Carolina facility. The team began joining large fuselage sections of the newest 787 Nov. 22 on schedule, a proud milestone for the South Carolina team and a...
 
 
Lockheed Martin image

Ball Aerospace equips Orion mission with key avionics, antenna hardware

Lockheed Martin image Ball Aerospace & Technologies Corp. is providing the phased array antennas and flight test cameras to prime contractor Lockheed Martin for Orion’s Exploration Flight Test-1 (EFT-1), which is an u...
 
 

Salina, Kansas, recalls anniversary of shuttered base

It has been 50 years this month since the announcement that Schilling Air Force Base was closing rattled Salina residents. The Salina Journal, which carried news of the closure in its Nov. 19, 1964, editions, reported that the economic disaster then spared no part of the community – real estate, retail, civic involvement, church attendance,...
 




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>