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Astronomers Uncover A Surprising Trend In Galaxy Evolution

October 21, 2012 Leave a comment

A comprehensive study of hundreds of galaxies observed by the Keck telescopes in Hawaii and NASA’s Hubble Space Telescope has revealed an unexpected pattern of change that extends back 8 billion years, or more than half the age of the universe.

“Astronomers thought disk galaxies in the nearby universe had settled into their present form by about 8 billion years ago, with little additional development since,” said Susan Kassin, an astronomer at NASA’s Goddard Space Flight Center in Greenbelt, Md., and the study’s lead researcher. “The trend we’ve observed instead shows the opposite, that galaxies were steadily changing over this time period.”

Today, star-forming galaxies take the form of orderly disk-shaped systems, such as the Andromeda Galaxy or the Milky Way, where rotation dominates over other internal motions. The most distant blue galaxies in the study tend to be very different, exhibiting disorganized motions in multiple directions. There is a steady shift toward greater organization to the present time as the disorganized motions dissipate and rotation speeds increase. These galaxies are gradually settling into well-behaved disks.

Full Story and Videos: http://www.nasa.gov/topics/universe/features/galaxy-evol.html
Also: http://hipacc.ucsc.edu/GalaxyDiskSettling.html

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ESA Science Programme’s New Small Satellite Will Study Super-Earths

October 21, 2012 Leave a comment

Studying planets around other stars will be the focus of the new small Science Programme mission, Cheops, ESA announced today. Its launch is expected in 2017.

Cheops – for CHaracterising ExOPlanets Satellite – will target nearby, bright stars already known to have planets orbiting around them.

Through high-precision monitoring of the star’s brightness, scientists will search for the telltale signs of a ‘transit’ as a planet passes briefly across its face.

In turn, this will allow an accurate measurement of the radius of the planet. For those planets with a known mass, the density will be revealed, providing an indication of the internal structure.

Full Story: http://www.esa.int/esaCP/SEMXFG4S18H_index_0.html

Poetry In Motion: Rare Polar-Ring Galaxy Captured In New Image

October 21, 2012 Leave a comment

Credit: Gemini Observatory/AURA

When the lamp is shattered,
The light in the dust lies dead.
When the cloud is scattered,
The rainbow’s glory is shed.

These words, which open Shelley’s poem “When the Lamp is Shattered,” employ visions of nature to symbolize life in decay and rebirth. It’s as if he had somehow foreseen the creation of this new Gemini Legacy image, and penned a caption for it. What Gemini has captured is nothing short of poetry in motion: the colorful and dramatic tale of a life-and-death struggle between two galaxies interacting. All the action appears in a single frame, with the stunning polar-ring galaxy NGC 660 as the focus of attention.

Polar-ring galaxies are peculiar objects. Astronomers have found only a handful of them, so not much is known about their origins. Most have an early-type spiral system, called a lenticular galaxy, as the central showpiece. But NGC 660, which lies about 40 million light-years distant toward the direction of Pisces the Fishes, is the only polar-ring galaxy known with what is called a late-type lenticular galaxy as its host. All, however, display a ring of stars, dust, and gas that extends tens of thousands of light-years across space along an orbit nearly perpendicular to the main disk.

Full Story: http://www.gemini.edu/node/11896

Radioactive Decay Of Titanium Powers Supernova Remnant

October 21, 2012 Leave a comment

Supernova remnant 1987A. Credits: ESA/Hubble & NASA

Supernova remnant SNR1987A is located 166 000 light-years away in the Large Magellanic Cloud. The light from the stellar explosion arrived at Earth in 1987, and has since provided astronomers with a natural laboratory to monitor how the brightness of a supernova changes over time.

The first detection of titanium-44 in supernova remnant 1987A. ESA’s Integral space telescope made the detection in the energy range between 65 keV and 82 keV, which brackets two emission lines produced during the decay of titanium-44, at 67.9 keV and 78.4 keV.

The detection required over 1000 hours of observation time with Integral.

Full Story: http://www.esa.int/esaSC/SEMBK54S18H_index_0.html
Also: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50934