Galaxy at the Edge

 

Tip: Click on Title for NASA image

Spiral galaxy NGC 4921 presently is estimated to be 320 million light years distant. This image, taken by the Hubble Space Telescope, is being used to identify key stellar distance markers known as Cepheid variable stars.

The magnificent spiral NGC 4921 has been informally dubbed anemic because of its low rate of star formation and low surface brightness.

Visible in the image are, from the center, a bright nucleus, a bright central bar, a prominent ring of dark dust, blue clusters of recently formed stars, several smaller companion galaxies, unrelated galaxies in the far distant universe, and unrelated stars in our Milky Way Galaxy. Image Credit: NASA, ESA, K. Cook (LLNL)

Winds of Change

This is a composite image of NGC 1068, one of the nearest and brightest galaxies containing a rapidly growing supermassive black hole. The X-ray images and spectra obtained using Chandra’s High Energy Transmission Grating Spectrometer show that a strong wind is being driven away from the center of NGC 1068 at a rate of about a million miles per hour. This wind is likely generated as surrounding gas is accelerated and heated as it swirls toward the black hole. A portion of the gas is pulled into the black hole, but some of it is blown away.

NGC 1068High energy X-rays produced by the gas near the black hole heat the ouflowing gas, causing it to glow at lower X-ray energies. X-ray data from the Chandra X-ray Observatory are shown in red, optical data from the Hubble Space Telescope in green and radio data from the Very Large Array in blue. The spiral structure of NGC 1068 is shown by the X-ray and optical data, and a jet powered by the central supermassive black hole is shown by the radio data.

This Chandra study is much deeper than previous X-ray observations. Using this data, researchers believe that each year several times the mass of our sun is being deposited out to large distances, about 3,000 light years from the black hole. The wind likely carries enough energy to heat the surrounding gas and suppress extra star formation.

These results help explain how a supermassive black hole can alter the evolution of its host galaxy. It has long been suspected that material blown away from a black hole can affect its environment, but a key question has been whether such “black hole blowback” typically delivers enough power to have a significant impact.

NGC 1068 is located about 50 million light years from Earth and contains a supermassive black hole about twice as massive as the one in the middle of the Milky Way Galaxy. Image Credit: X-ray (NASA/CXC/ MIT/C.Canizares, D.Evans et al), Optical (NASA/STScI), Radio (NSF/ NRAO/VLA)

In Search of Antimatter Galaxies



 


Next year, a powerful cosmic ray detector will be installed on the International Space Station. Its mission: to search for antimatter galaxies and other exotic phenomena in the Universe.


Click for large image: An artist's concept of the Alpha Magnetic Spectrometer installed on the International Space Station.

Click for large image: An artist's concept of the Alpha Magnetic Spectrometer installed on the International Space Station.

 

August 14, 2009: NASA’s space shuttle program is winding down. With only about half a dozen more flights, shuttle crews will put the finishing touches on the International Space Station (ISS), bringing to an end twelve years of unprecedented orbital construction. The icon and workhorse of the American space program will have finished its Great Task.

 

An act of Congress in 2008 added another flight to the schedule near the end of the program. Currently scheduled for 2010, this extra flight of the shuttle is going to launch a hunt for antimatter galaxies.

The device that does the actual hunting is called the Alpha Magnetic Spectrometer–or AMS for short. It’s a $1.5 billion cosmic ray detector that the shuttle will deliver to the ISS. [...]

 

 

Source: Nasa Science – click here for full article