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Coma Cluster: Clues To The Growth Of The Colossus In Coma

September 19, 2013 Leave a comment

Credit: X-ray: NASA / CXC / MPE / J.Sanders et al, Optical: SDSS

Credit: X-ray: NASA / CXC / MPE / J.Sanders et al, Optical: SDSS

A team of astronomers has discovered enormous arms of hot gas in the Coma cluster of galaxies by using NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton. These features, which span at least half a million light years, provide insight into how the Coma cluster has grown through mergers of smaller groups and clusters of galaxies to become one of the largest structures in the Universe held together by gravity.

A new composite image, with Chandra data in pink and optical data from the Sloan Digital Sky Survey appearing in white and blue, features these spectacular arms (mouse over the image for their location). In this image, the Chandra data have been processed so extra detail can be seen.

The X-ray emission is from multimillion-degree gas and the optical data shows galaxies in the Coma Cluster, which contain only about 1/6 the mass in hot gas. Only the brightest X-ray emission is shown here, to emphasize the arms, but the hot gas is present over the entire field of view.

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Coma Cluster: Clues To The Growth Of The Colossus In Coma

September 19, 2013 Leave a comment

Credit: ESO. Acknowledgement: Martin Pugh

Credit: ESO. Acknowledgement: Martin Pugh

Located around 6000 light-years from Earth in the constellation of Scorpius (The Scorpion), the nebula formally known as IC 4628 is a huge region filled with gas and clumps of dark dust. These gas clouds are star-forming regions, producing brilliant hot young stars. In visible light, these stars appear as a blue-white colour, but they also emit intense radiation in other parts of the spectrum — most notably in the ultraviolet.

It is this ultraviolet light from the stars that causes the gas clouds to glow. This radiation strips electrons from hydrogen atoms, which then later recombine and release energy in the form of light. Each chemical element emits light at characteristic colours when this process occurs, and for hydrogen the predominant colour is red. IC 4628 is an example of an HII region.

Over the last few million years this region of sky has formed many stars, both individually and in clusters. There is a large scattered star cluster named Collinder 316 which extends over most of this image. This cluster is a part of a much larger gathering of very hot and luminous stars. Also visible are many dark structures or cavities, where interstellar matter has been blown away by the powerful winds generated by the nearby hot stars.

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The Inside Of Our Milky Way In 3D

September 19, 2013 Leave a comment

Scientists at the Max Planck Institute for Extraterrestrial Physics have produced the first detailed three-dimensional map of the stars that form the inner regions of our Milky Way, using publicly available VVV survey data from the science archive facility at ESO. They find a box/peanut shaped bulge with an elongated bar and a prominent X-structure, which had been hinted at in previous studies. This indicates that the Milky Way was originally a pure disk of stars, which then formed a thin bar, before buckling into the box/peanut shape seen today. The new map can be used for more detailed studies of the dynamics and evolution of our Milky Way.

Our Sun resides right inside the galactic disk, about 27 000 light-years from the core of our Milky Way. Due to the obscuring effects of dense gas and dust clouds it is therefore difficult to get accurate information about the shape and properties of the inner regions of our galaxy. By using a large number of so-called “red clump” giant stars from the new VVV survey scientists at the Max Planck Institute for Extraterrestrial Physics have now produced a three-dimensional map of the galactic bulge.

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Magnetic Jet Shows How Stars Begin Their Final Transformation

September 19, 2013 Leave a comment

Credits: E. Lagadec/ESO/A. Pérez Sánchez

Credits: E. Lagadec/ESO/A. Pérez Sánchez

An international team of astronomers have for the first time found a jet of high-energy particles emanating from a dying star. The discovery, by a collaboration of scientists from Sweden, Germany and Australia, is a crucial step in explaining how some of the most beautiful objects in space are formed – and what happens when stars like the sun reach the end of their lives. The researchers publish their results in the journal Monthly Notices of the Royal Astronomical Society.

At the end of their lives, stars like the sun transform into some of the most beautiful objects in space: amazing symmetric clouds of gas called planetary nebulae. But how planetary nebulae get their strange shapes has long been a mystery to astronomers.

Scientists at Chalmers University of Technology in Sweden have together with colleagues from Germany and Australia discovered what could be the key to the answer: a high-speed, magnetic jet from a dying star.

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New Hubble Image Of Galaxy Cluster Abell 1689

September 19, 2013 1 comment

Image credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Blakeslee (NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory), and H. Ford (JHU)

Image credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Blakeslee (NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory), and H. Ford (JHU)

Hubble previously observed this cluster back in 2002. However, this new image combines visible and infrared data from Hubble’s Advanced Camera for Surveys (ACS) to reveal this patch of sky in greater detail than ever before, with a combined total exposure time of over 34 hours.

These new, deeper, observations were taken in order to explore the globular clusters within Abell 1689 [1]. This new study has shown that Abell 1689 hosts the largest population of globular clusters ever found. While our galaxy, the Milky Way, is only home to around 150 of these old clumps of stars, Hubble has spied some 10 000 globular clusters within Abell 1689. From this, the astronomers estimate that this galaxy cluster could possibly contain over 160 000 globulars overall – an unprecedented number.

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NASA’s Voyager 1 Reaches Interstellar Space

September 19, 2013 Leave a comment

NASA’s Voyager 1 spacecraft officially is the first human-made object to venture into interstellar space. The 36-year-old probe is about 12 billion miles (19 billion kilometers) from our sun.

New and unexpected data indicate Voyager 1 has been traveling for about one year through the plasma, or ionized gas, present in the space between the stars. Voyager is in a transitional region immediately outside the solar bubble, where some effects from our sun are still evident. A report on the analysis of these new data, an effort led by Don Gurnett and the plasma wave science team at the University of Iowa, Iowa City, is published this week in the journal Science.

“The crossing is like Voyager leaving the hot, million-degree atmosphere of the sun and entering into a region dominated by the ‘cold,’ 5,000-degree atmosphere of the galaxy,” says APL’s Stamatios (Tom) Krimigis, principal investigator for Voyager’s Low-Energy Charged Particle (LECP) instrument. “It’s like the first time a satellite [Sputnik] went beyond Earth’s atmosphere to an altitude of some 600 miles; Voyager is now leaving the solar bubble at an altitude of 11.3 billion miles. It’s another historic milestone.”

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“Red Nugget” Galaxies Were Hiding In Plain Sight

September 19, 2013 1 comment

In 2005 the Hubble Space Telescope spotted unusually small galaxies densely packed with red stars in the distant, young universe. They were nicknamed “red nuggets,” not only because they are small and red but also their existence challenged current theories of galaxy formation, making them precious in astronomers’ eyes.

Since no “red nuggets” were seen nearby, astronomers wondered why they had disappeared over time. New research shows that they didn’t disappear completely. In fact, they were simply hidden within the data of previous surveys.

Astronomers now realize these newfound compact galaxies could represent a missing link between distant “red nuggets” and nearby elliptical galaxies. They may light the evolutionary path to show how compact galaxies age over time and reveal whether they become the “seeds” for the monster ellipticals we see today.

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