Archive for May 16, 2012

Baby Galaxies Grew Up Quickly

May 16, 2012 1 comment

Baby galaxies from the young Universe more than 12 billion years ago evolved faster than previously thought, shows new research from the Niels Bohr Institute. This means that already in the early history of the Universe, there was potential for planet formation and life.  The research results have been published in the scientific journal, Monthly Notices of the Royal Astronomical Society Letters.
For several thousand years after the Big Bang 13.7 billion years ago, the Universe consisted of a hot, dense primordial soup of gases and particles. But the Universe was expanding rapidly and the primordial soup became less dense and cooled. However, the primordial soup was not evenly distributed, but was denser in some areas than others. The density in some of the densest areas increased due to gravity and began to contract, forming the first stars and galaxies. This took place approximately 500 million years after the Big Bang.
The earliest galaxies were probably comprised of primitive, giant stars that consisted of only hydrogen and helium. There were no heavier elements. They first appeared later in the evolution of the Universe, created by nuclear processes in the stars.
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Mercury’s Magnetic Field Measured By MESSENGER Orbiter

May 16, 2012 1 comment

Researchers working with NASA’s Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) spacecraft report the frequent detections of Kelvin-Helmholtz (KH) waves at the edge of the innermost planet’s magnetosphere. In six different sets of magnetic field measurements made by the orbiter as it passed through Mercury’s magnetopause, the boundary that separates the planet’s magnetosphere from the solar wind plasma in the magnetosheath, Sundberg et al. detect the magnetic field oscillations characteristic of fully developed KH waves.

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Slooh Space Camera to Broadcast Live Feed of Annular Solar Eclipse from Japan to the United States

Slooh Space Camera will broadcast a free, real-time feed of the Annular Solar Eclipse live from telescope feeds in Japan, California, Arizona, and New Mexico. Viewers can capture a first look of the eclipse on Slooh, Sunday, May 20th starting at 2:30 PM PDT / 5:30 PM EDT / 21:30 UTC as the Moon’s shadow begins its journey over Japan. Slooh will track the eclipse as it leaves Japan and lands on the shores of the Western United States starting at 5:00 PM PDT / 8:00 PM EDT / 00:00 UTC (5/21), where their professional broadcast team of astronomy luminaries and solar experts will pick-up the event and explain what you are seeing.

The full broadcast can be accessed at Slooh’s homepage, where viewers will be able to snap and share eclipse pics directly from Slooh live feeds to their Pinterest boards. Furthermore, viewers will be treated to an impressive panel of guests, including BBC contributor, Dr. Lucie Green, solar researcher at the Mullard Space Science Laboratory, UCL’s Department of Space and Climate Physics, and Bob Berman, author of The Sun’s Heartbeat and contributing editor and monthly columnist for Astronomy Magazine.

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Fuel For The Black Hole: First Investigations Of A Galactic NucleusWith The Amber Instrument Of The Very Large Telescope Interferometer In Chile

May 16, 2012 1 comment

An international research team led by Gerd Weigelt from the Max-Planck-Institut für Radioastronomie in Bonn reports on high-resolution studies of an active galactic nucleus in the near-infrared. The observations were carried out with the Very Large Telescope Interferometer (VLTI) of the European Southern Observatory (ESO). The use of near-infrared interferometry allowed the team to resolve a ring-shaped dust distribution (generally called “dust torus”) in the inner region of the nucleus of the active galaxy NGC 3783. This dust torus probably represents the reservoir of gaseous and dusty material that “feeds” the hot gas disk (“accretion disk”) and the supermassive black hole in the center of this galaxy. The resolved dust torus has an angular radius of only 0.7 milli-arcseconds on the sky, an angle that is 5 million times smaller than one degree. This angular radius corresponds to a radius of approximately 0.5 light years for a distance of 150 million light years. Studies of the physical properties of these dust tori are very important to improve our understanding of their structure and interaction with the accretion disk. To obtain these measurements, the light from up to three telescopes of the Very Large Telescope Interferometer was interferometrically combined. This method is able to achieve an angular resolution equivalent to the resolution of a telescope with a diameter of 130 Meters.

Extreme physical processes occur in the innermost regions of galactic nuclei. Supermassive black holes were discovered in many galaxies. The masses of these black holes are often a millionfold larger than the mass of our sun. These central black holes are surrounded by hot and bright gaseous disks, called “accretion disks”. The emitted radiation from these accretion disks is probably generated by infalling material. To maintain the high luminosity of the accretion disk, fresh material has to be permanently supplied. The dust tori (see Fig. 1) surrounding the accretion disks are most likely the reservoir of the material that flows through the accretion disk and finally “feeds” the growing black hole.

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A Supernova Cocoon Breakthrough

Observations with NASA’s Chandra X-ray Observatory have provided the first X-ray evidence of a supernova shock wave breaking through a cocoon of gas surrounding the star that exploded. This discovery may help astronomers understand why some supernovas are much more powerful than others.

On Nov. 3, 2010, a supernova was discovered in the galaxy UGC 5189A, located about 160 million light years away. Using data from the All Sky Automated Survey telescope in Hawaii taken earlier, astronomers determined this supernova exploded in early October 2010 (in Earth’s time-frame).

A team of researchers used Chandra to observe this supernova in December 2010 and again in October 2011. The supernova was one of the most luminous that has ever been detected in X-rays.

In the first Chandra observation of SN 2010jl, the X-rays from the explosion’s blast wave were strongly absorbed by a cocoon of dense gas around the supernova. This cocoon was formed by gas blown away from the massive star before it exploded.

In the second observation taken almost a year later, there is much less absorption of X-ray emission, indicating that the blast wave from the explosion has broken out of the surrounding cocoon. The Chandra data show that the gas emitting the X-rays has a very high temperature — greater than 100 million degrees Kelvin – strong evidence that it has been heated by the supernova blast wave.

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