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Pulsar in Triple Stellar System

Astronomers using the National Science Foundation's Green Bank Telescope (GBT) have discovered a unique stellar system of two white dwarf stars and a superdense neutron star, all packed within a space smaller than Earth's orbit around the Sun. The closeness of the stars, combined with their nature, has allowed the scientists to make the best measurements yet of the complex gravitational interactions in such a system.  In addition, detailed studies of this system may provide a key clue for resolving one of the principal outstanding problems of fundamental physics -- the true nature of gravity.

 


 

Magnetic 'Force Field' May Save Giant Gas Cloud During Milky Way Collision

A gigantic streamer of hydrogen gas, called the Smith Cloud, is on a collision course for the Milky Way. Now, though, it seems that this cloud's seemingly inevitable doom may be avoided. Scientists have discovered a magnetic field deep in the cloud's interior, which may protect it during its meteoric plunge into the disk of our galaxy.  Currently, the Smith Cloud is hurtling toward the Milky Way at an astonishing 150 miles per second. Known as a high velocity cloud (HVC), the Smith Cloud is predicted to hit in about 30 million years. When it does, it will set off a spectacular burst of star formation--assuming it survives careening through the halo of hot ionized gas surrounding the Milky Way.

 


 

'Jekyll and Hyde' star morphs from radio to X-ray pulsar and back again

Astronomers have uncovered the strange case of a neutron star with the peculiar ability to transform from a radio pulsar into an X-ray pulsar and back again. This star's capricious behavior appears to be fueled by a nearby companion star and may give new insights into the birth of millisecond pulsars. "What we're seeing is a star that is the cosmic equivalent of 'Dr. Jekyll and Mr. Hyde,' with the ability to change from one form to its more intense counterpart with startling speed," said Scott Ransom, an astronomer at the National Radio Astronomy Observatory (NRAO) in Charlottesville, Va. "Though we have known that X-ray binaries -- some of which are observed as X-ray pulsars -- can evolve over millions of years to become rapidly spinning radio pulsars, we were surprised to find one that seemed to swing so quickly between the two."


Astronomers Discover Surprising Clutch of Hydrogen Clouds Lurking among Our Galactic Neighbors

 

In a dark, starless patch of intergalactic space, astronomers have discovered a never-before-seen cluster of hydrogen clouds strewn between two nearby galaxies, Andromeda (M31) and Triangulum (M33). The researchers speculate that these rarefied blobs of gas - each about as massive as a dwarf galaxy - condensed out of a vast and as-yet undetected reservoir of hot, ionized gas, which could have accompanied an otherwise invisible band of dark matter.

 

Einstein's gravity theory passes toughest test yet


An extreme pair of superdense stars orbiting each other has put Einstein's general theory of relativity to its toughest test yet, and the crazy-haired physicist still comes out on top.  About 7,000 light-years from Earth, an exceptionally massive neutron star that spins around 25 times a second is orbited by a compact, white dwarf star. The gravity of this system is so intense that it offers an unprecedented testing ground for theories of gravity. Scientists know general relativity, proposed by Albert Einstein in 1915, isn't the complete story. While it does very well describing large, massive systems, it's incompatible with quantum mechanics, which governs the physics of the very small. For something extremely small, yet extremely massive — such as a black hole — the two theories contradict each other, and scientists are left without a physical description.

 

Massive Outburst in Neighbor Galaxy Surprises Astronomers

The surprising discovery of a massive outburst in a neighboring galaxy is giving astronomers a tantalizing look at what likely is a powerful belch by a gorging black hole at the galaxy's center. The scientists were conducting a long-term study of molecules in galaxies, when one of the galaxies showed a dramatic change. "The discovery was entirely serendipitous. Our observations were spread over a few years, and when we looked at them, we found that one galaxy had changed over that time from being placid and quiescent, to undergoing a hugely energetic outburst at the end," said Robert Minchin, of Arecibo Observatory, who presented the research

Students use Radio Telescope to Explore the Universe

A new program is giving middle-school-aged youth the chance to take remote control of a large, research-grade radio telescope and expand their cosmic explorations beyond what the eye can see. The National Radio Astronomy Observatory’s (NRAO) 20-meter-diameter telescope in Green Bank, West Virginia, is joining a global network of telescopes bringing the excitement of hands-on research to young people via 4-H, the nation’s largest youth development organization

Student Team Discovers New Interstellar Molecule

Chemists can spend entire careers in search of new molecules in space; on average, only about four or five interstellar molecules are discovered worldwide each year.  Recently, a team of undergraduate students from four universities visiting the University of Virginia to take part in a special eight-week summer research program for minority students made one of those rare discoveries. It's called cyanomethanimine, and is considered a precursor molecule for RNA, a key building block for the development of life on this planet – and possibly elsewhere in the universe.  The students conducted experiments in the astrochemistry lab of chemist Brooks Pate of U.Va.'s College of Arts & Sciences and used data from the National Radio Astronomy Observatory's Green Bank Telescope in Green Bank, W.Va., to verify their finding.

Galaxies passing closely created big gas 'bridge'

Two galaxies near our own Milky Way may have had a close encounter billions of years ago that created a vast bridge of gas that links them together to this day, a new study finds.  Observations from the National Science Foundation's Green Bank Telescope, a massive radio instrument in Green Bank, W.Va., indicate that hydrogen gas may be streaming between the colossal Andromeda Galaxy, or M31, and its neighboring Triangulum Galaxy, or M33.

Rare Peek at Early Stage of Star Formation

Star Formation

Using radio and infrared telescopes, astronomers have obtained a first tantalizing look at a crucial early stage in star formation. The new observations promise to help scientists understand the early stages of a sequence of events through which a giant cloud of gas and dust collapses into dense cores that, in turn, form new stars.

Resolving Cluster Dynamics with the GBT

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A multi-wavelength composite image of MACS0744. White contours show the MUSTANG+GBT detection of the SZE. Red shows the X-ray surface brightness as measured by the Chandra X-ray Observatory. Green is the optical emission from the Hubble Space Telescope. Blue contours and color-scale show the gravitational lensing mass reconstruction from Johan Richard. The resolved SZ image reveals a kidney-shaped ridge coincident with a sharp X-ray discontinuity interpreted as a bow shock in the ICM. The feature is located perpendicular to the mass elongation revealed by the lensing analysis, suggestive of a scenario in which an infalling subcluster has been stripped of its baryons after passing through the main core.

Most Massive Neutron Star Yet Known

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Astronomers using the National Science Foundation's Green Bank Telescope (GBT) have discovered the most massive neutron star yet found, a discovery with strong and wide-ranging impacts across several fields of physics and astrophysics...  (Nature 2010 467, p. 1081)