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domingo, 2 de noviembre de 2014

NASA : NASA’S Chandra Observatory Identifies Impact of Cosmic Chaos on Star Birth .- Observatorio Espacial Chandra de la NASA Identifica Impacto Cosmico como un Caos en el Nacimiento de una estrella......

Hola amigos: A VUELO DE UN QUINDE EL BLOG., la Agencia Espacial NASA, nos alcanza la información del nacimiento de una estrella que se produce como un impacto  generando un caos cósmico, NASA nos dice: ...."El mismo fenómeno que hace que un viaje en avión accidentado, turbulencia, puede ser la solución a un misterio de larga data sobre el nacimiento de las estrellas, o la ausencia de ella, de acuerdo con un nuevo estudio usando datos del Observatorio de rayos X Chandra de la NASA................Los cúmulos de galaxias son los objetos más grandes del Universo, se mantienen unidos por la gravedad. Estos gigantes contienen cientos o miles de galaxias individuales que están inmersos en el gas con temperaturas de millones de grados...............Este gas caliente, que es el componente económico más grande de los cúmulos de galaxias aparte de la materia oscura invisible, brilla intensamente en luz de rayos X detectados por el Chandra. Con el tiempo, el gas en los centros de estos grupos debe enfriar lo suficiente para que las estrellas se forman a un ritmo prodigioso. Sin embargo, esto no es lo que los astrónomos han observado en muchos cúmulos de galaxias..........."Sabíamos que de alguna manera el gas en los cúmulos se calienta para prevenir que el enfriamiento y la formación de estrellas. La pregunta era exactamente cómo ", dijo Irina Zhuravleva de la Universidad de Stanford en Palo Alto, California, quien dirigió el estudio que aparece en la última edición en línea de la revista Nature. "Creemos que podemos tener evidencia encontrada que el calor se canaliza de movimientos turbulentos, que identificamos de firmas registradas en las imágenes de rayos X"........Observaciones de Chandra de los cúmulos de galaxias de Perseo y Virgo sugieren turbulencia puede prevenir que el gas caliente no se enfríe, dirigiéndose a una pregunta de larga data de los cúmulos de galaxias no se forman un gran número de estrellas......
Chandra observations of the Perseus and Virgo galaxy clusters suggest turbulence may be preventing hot gas there from cooling, addressing a long-standing question of galaxy clusters do not form large numbers of stars.
Chandra observations of the Perseus and Virgo galaxy clusters suggest turbulence may be preventing hot gas there from cooling, addressing a long-standing question of galaxy clusters do not form large numbers of stars.
Image Credit: 
NASA/CXC/Stanford/I. Zhuravleva et al
The same phenomenon that causes a bumpy airplane ride, turbulence, may be the solution to a long-standing mystery about stars’ birth, or the absence of it, according to a new study using data from NASA’s Chandra X-ray Observatory.
Galaxy clusters are the largest objects in the universe, held together by gravity.  These behemoths contain hundreds or thousands of individual galaxies that are immersed in gas with temperatures of millions of degrees.
This hot gas, which is the heftiest component of the galaxy clusters aside from unseen dark matter, glows brightly in X-ray light detected by Chandra. Over time, the gas in the centers of these clusters should cool enough that stars form at prodigious rates. However, this is not what astronomers have observed in many galaxy clusters.
“We knew that somehow the gas in clusters is being heated to prevent it cooling and forming stars. The question was exactly how,” said Irina Zhuravleva of Stanford University in Palo Alto, California, who led the study that appears in the latest online issue of the journal Nature. “We think we may have found evidence that the heat is channeled from turbulent motions, which we identify from signatures recorded in X-ray images.”
Prior studies show supermassive black holes, centered in large galaxies in the middle of galaxy clusters, pump vast quantities of energy around them in powerful jets of energetic particles that create cavities in the hot gas. Chandra, and other X-ray telescopes, have detected these giant cavities before.
The latest research by Zhuravleva and her colleagues provides new insight into how energy can be transferred from these cavities to the surrounding gas. The interaction of the cavities with the gas may be generating turbulence, or chaotic motion, which then disperses to keep the gas hot for billions of years.
“Any gas motions from the turbulence will eventually decay, releasing their energy to the gas,” said co-author Eugene Churazov of the Max Planck Institute for Astrophysics in Munich, Germany. “But the gas won’t cool if turbulence is strong enough and generated often enough.”
The evidence for turbulence comes from Chandra data on two enormous galaxy clusters named Perseus and Virgo. By analyzing extended observation data of each cluster, the team was able to measure fluctuations in the density of the gas. This information allowed them to estimate the amount of turbulence in the gas.
“Our work gives us an estimate of how much turbulence is generated in these clusters,” said Alexander Schekochihin of the University of Oxford in the United Kingdom. “From what we’ve determined so far, there’s enough turbulence to balance the cooling of the gas.
These results support the “feedback” model involving supermassive black holes in the centers of galaxy clusters. Gas cools and falls toward the black hole at an accelerating rate, causing the black hole to increase the output of its jets, which produce cavities and drive the turbulence in the gas. This turbulence eventually dissipates and heats the gas.
While a merger between two galaxy clusters may also produce turbulence, the researchers think that outbursts from supermassive black holes are the main source of this cosmic commotion in the dense centers of many clusters.
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
An interactive image, podcast, and video about these findings are available at:
For more Chandra images, multimedia and related materials, visit:
NASA
Guillermo Gonzalo Sánchez Achutegui
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