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‘Perfect Storm’ Quenching Star Formation Around A Supermassive Black Hole

December 17, 2014 Leave a comment

A combined Hubble Space Telescope / ALMA image of NGC 1266. Credit: NASA/ESA Hubble; ALMA (NRAO/ESO/NAOJ)

A combined Hubble Space Telescope / ALMA image of NGC 1266. Credit: NASA/ESA Hubble; ALMA (NRAO/ESO/NAOJ)

High-energy jets powered by supermassive black holes can blast away a galaxy’s star-forming fuel, resulting in so-called “red and dead” galaxies: those brimming with ancient red stars yet containing little or no hydrogen gas to create new ones.

Now astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered that black holes don’t have to be nearly so powerful to shut down star formation. By observing the dust and gas at the center of NGC 1266, a nearby lenticular galaxy with a relatively modest central black hole, the astronomers have detected a “perfect storm” of turbulence that is squelching star formation in a region that would otherwise be an ideal star factory.

This turbulence is stirred up by jets from the galaxy’s central black hole slamming into an incredibly dense envelope of gas. This dense region, which may be the result of a recent merger with another smaller galaxy, blocks nearly 98 percent of material propelled by the jets from escaping the galactic center.

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Venus Express Goes Gently Into The Night

December 17, 2014 Leave a comment

Copyright ESA–C. Carreau

Copyright ESA–C. Carreau

ESA’s Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year.

Since its arrival at Venus in 2006, Venus Express had been on an elliptical 24‑hour orbit, traveling 66 000 km above the south pole at its furthest point and to within 200 km over the north pole on its closest approach, conducting a detailed study of the planet and its atmosphere.

However, after eight years in orbit and with propellant for its propulsion system running low, Venus Express was tasked in mid-2014 with a daring aerobraking campaign, during which it dipped progressively lower into the atmosphere on its closest approaches to the planet.

Normally, the spacecraft would perform routine thruster burns to ensure that it did not come too close to Venus and risk being lost in the atmosphere. But this unique adventure was aimed at achieving the opposite, namely reducing the altitude and allowing an exploration of previously uncharted regions of the atmosphere.

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Surprising Theorists, Stars Within Middle-Aged Clusters Are Of Similar Age

December 17, 2014 Leave a comment

Image: NASA/ESA Hubble Space Telescope/Fabian RRRR

Image: NASA/ESA Hubble Space Telescope/Fabian RRRR

A close look at the night sky reveals that stars don’t like to be alone; instead, they congregate in clusters, in some cases containing as many as several million stars. Until recently, the oldest of these populous star clusters were considered well understood, with the stars in a single group having formed at different times, over periods of more than 300 million years. Yet new research published online today in the journal Nature suggests that the star formation in these clusters is more complex.

Using data from the Hubble Space Telescope, a team of researchers at the Kavli Institute for Astronomy and Astrophysics (KIAA) at Peking University and the Chinese Academy of Science’s National Astronomical Observatories in Beijing have found that, in large middle-aged clusters at least, all stars appear to be of about the same age.

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