This new image of Centaurus A combines ALMA and near-infrared observations of the massive elliptical radio galaxy. The green parts show gas coming towards us while more orange features depict gas moving away.
Picture: ESO / BEL/AFP/GettyImages
Friday, June 1, 2012
Nasa Cassini Image: Geyser on Saturn's Moon Enceladus
A geyser is seen on Saturn's moon Enceladus in this image by NASA's Cassini mission. Scientists used views like this to help them identify the source locations for individual jets spurting ice particles, water vapour and trace organic compounds from the surface of Enceladus.
Picture: REUTERS/NASA/JPL/Space Science Institute
Image of a Very Distant Future: Milky Way Collides with Andromeda Galaxy
This Nasa illustration shows at night just before the predicted merger between our Milky Way galaxy and the neighbouring Andromeda galaxy, which is expected to happen about 3.75 billion years from now
Picture: REUTERS/NASA, ESA, Z. Levay and R. van der Marel (STScI), and A. Mellinger
SpaceX: Scorched Dragon on board Recovery Craft
SpaceX Dragon looking scorched and burned after re-entry sits safely on the barge after being retrieved from the Pacific Ocean after splashdown.
Thursday, May 31, 2012
SpaceX Dragon Splashes down after pioneering mission
SpaceX's Dragon capsule splashed down in the Pacific Ocean at 11:42 a.m. EDT a few hundred miles west of Baja California, Mexico, marking a successful end to the first mission by a commercial company to resupply the International Space Station.
ESO ALMA Turns Its Eyes to Centaurus A
Centaurus A is a massive elliptical "radio galaxy," (a galaxy that emits strong radio waves) and is the most prominent, as well as the nearest, radio galaxy in the sky. Its very luminous center hosts a supermassive black hole with a mass of about 100 million times that of the Sun.
As seen in visible light, a dark dusty band obscures the galaxy's center. This dust lane harbors large amounts of gas, dust and young stars. These features, together with the strong radio emission, indicate that Centaurus A is the result of a collision between a giant elliptical galaxy and a smaller spiral galaxy.
To see through the obscuring dust in the central band, astronomers need to observe using longer wavelengths of light, such as infrared light or radio waves.
The new ALMA observations, shown in a gradation of blue in this image, reveal the position and motion of clouds of gas in the galaxy.
They are the sharpest and most sensitive such observations ever made. ALMA was tuned to detect signals with a wavelength around 1.3 millimeters, emitted by molecules of carbon monoxide gas.
The motion of the gas in the galaxy causes slight changes to this wavelength, shown in this image as changes in color. Violet and dark-blue features trace gas coming towards us, while light-blue features depict gas moving away.
We can see that the gas to the left of the center is moving towards us, while the gas to the right of the center is moving away from us, indicating that the gas is orbiting around the galaxy.
The millimeter wavelength observations were made using super-sensitive radio receivers built by the National Radio Astronomy Observatory. In this image the ALMA observations are overlaid on an optical image of Centaurus A produced by the MPG/ESO 2.2-meter telescope at ESO's La Silla Observatory in Chile.
Construction of ALMA, on the Chajnantor Plateau in northern Chile, will be completed in 2013, when 66 high-precision antennas will be fully operational. Half of the antennas already are installed. Early scientific observations with a partial array began in 2011, and already are producing outstanding results. The ALMA observations of Centaurus A shown here were taken during the telescope's Commissioning and Science Verification phase.
Credit: ALMA (ESO/NAOJ/NRAO), T.A. Rector (University of Alaska Anchorage). Visible-light image: ESO
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