Archive

Archive for June 20, 2013

Dusty Surprise Around Giant Black Hole


Artist’s impression. Credit: ESO/M. Kornmesser

Artist’s impression. Credit: ESO/M. Kornmesser

ESO’s Very Large Telescope Interferometer has gathered the most detailed observations ever of the dust around the huge black hole at the centre of an active galaxy. Rather than finding all of the glowing dust in a doughnut-shaped torus around the black hole, as expected, the astronomers find that much of it is located above and below the torus. These observations show that dust is being pushed away from the black hole as a cool wind — a surprising finding that challenges current theories and tells us how supermassive black holes evolve and interact with their surroundings.

Over the last twenty years, astronomers have found that almost all galaxies have a huge black hole at their centre. Some of these black holes are growing by drawing in matter from their surroundings, creating in the process the most energetic objects in the Universe: active galactic nuclei (AGN). The central regions of these brilliant powerhouses are ringed by doughnuts of cosmic dust dragged from the surrounding space, similar to how water forms a small whirlpool around the plughole of a sink. It was thought that most of the strong infrared radiation coming from AGN originated in these doughnuts.

But new observations of a nearby active galaxy called NGC 3783, harnessing the power of the Very Large Telescope Interferometer (VLTI) at ESO’s Paranal Observatory in Chile [2], have given a team of astronomers a surprise.

Full Story: http://www.eso.org/public/news/eso1327/

Billion-Pixel View Of Mars Comes From Curiosity Rover


Image credit: NASA/JPL-Caltech/MSSS

Image credit: NASA/JPL-Caltech/MSSS

A billion-pixel view from the surface of Mars, from NASA’s Mars rover Curiosity, offers armchair explorers a way to examine one part of the Red Planet in great detail.

The first NASA-produced view from the surface of Mars larger than one billion pixels stitches together nearly 900 exposures taken by cameras onboard Curiosity and shows details of the landscape along the rover’s route.

The full-circle scene surrounds the site where Curiosity collected its first scoops of dusty sand at a windblown patch called “Rocknest,” and extends to Mount Sharp on the horizon.

“It gives a sense of place and really shows off the cameras’ capabilities,” said Bob Deen of the Multi-Mission Image Processing Laboratory at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “You can see the context and also zoom in to see very fine details.”

Full Story and Image Links: http://www.jpl.nasa.gov/news/news.php?release=2013-205

Texas Astronomers Discover Pulsations In Crystalized, Dying Star


Astronomers from The University of Texas at Austin and colleagues have used the 2.1-meter Otto Struve Telescope at the university’s McDonald Observatory to discover pulsations from the crystalized remnant of a burnt-out star. The finding will allow astronomers to see below the star’s atmosphere and into its interior, much like earthquakes allow geologists to study compositions below Earth’s surface. The findings appear in the current issue of The Astrophysical Journal Letters.

The Texas astronomers made their discovery in collaboration with astronomers from Brazil’s Universidade Federal do Rio Grande do Sul, the University of Oklahoma, and the Smithsonian Astrophysical Observatory.

The star, GD 518, is roughly 170 light years from Earth in the constellation Draco, but far too faint to be seen without a telescope. It is a white dwarf, a star at the end of its life cycle that is essentially just a burnt-out core, the ashy byproduct of previous epochs of nuclear fusion.

The star is unique in that much of it is likely suspended in a state more akin to a solid than a liquid or gas. The interiors of dying stars can become crystalized similar to the way in which frigid water freezes into ice, like the slow formation of glaciers in cooling ocean water.

Full Story: http://mcdonaldobservatory.org/news/releases/2013/06/19

Hubble Spots Galaxies In Close Encounter


Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

The NASA/ESA Hubble Space Telescope has produced this vivid image of a pair of interacting galaxies known as Arp 142. When two galaxies stray too close to each other they begin to interact, causing spectacular changes in both objects. In some cases the two can merge — but in others, they are ripped apart.

Just below the centre of this image is the blue, twisted form of galaxy NGC 2936, one of the two interacting galaxies that form Arp 142 in the constellation of Hydra. Nicknamed “the Penguin” or “the Porpoise” by amateur astronomers, NGC 2936 used to be a standard spiral galaxy before being torn apart by the gravity of its cosmic companion.

The remnants of its spiral structure can still be seen — the former galactic bulge now forms the “eye” of the penguin, around which it is still possible to see where the galaxy’s pinwheeling arms once were. These disrupted arms now shape the cosmic bird’s “body” as bright streaks of blue and red across the image. These streaks arch down towards NGC 2936’s nearby companion, the elliptical galaxy NGC 2937, visible here as a bright white oval. The pair show an uncanny resemblance to a penguin safeguarding its egg.

Full Story and Links: http://www.spacetelescope.org/news/heic1311/