Saturday, September 14, 2013

Most detailed 3D map of the inner Milky Way developed -

Garching – The inner regions of our galaxy look like an unshelled peanut. Such as the European Southern Observatory (ESO) announced in Garching near Munich, were able to create the most detailed three-dimensional map of the central region of our Milky Way, two international research teams with data from ESO telescopes. This provided the researchers found that the inner regions from certain angles X-shaped, look for other peanut-shaped.

Partial view

“Bulge” is known in the astronomy of the dense central region of a spiral galaxy (English for bulge). The “bulge” stands out clearly from the rest of the galaxy and appears much brighter due to its high density. Thus, the “bulge” is one of the most central and most massive regions even in the case of our home galaxy. This central bulge consists of about 10 billion stars and has a diameter of thousands of light years. So far, however, it was not able to understand their structure and origin.

because the view from Earth to the region – at a distance of about 27,000 light years – is severely restricted by dense gas and dust clouds. Astronomers can only get a good look at the “bulge” when they observe at longer wavelengths, such as in infrared light can penetrate dust clouds.

22 million stars identified

Previous observations had already hinted that the “bulge” could have an X-shaped structure. Now, two groups of researchers were able to gain a much clearer view of the structure on the basis of new observations by several ESO telescopes.

scientists from the Max Planck Institute for extraterrestrial Physics (MPE) in Garching, the data used to VISTA telescope at ESO’s Paranal Observatory in Chile. There is a sky survey since 2012 as part of the investigation Vista Variables in the Via Lactea (VVV) is carried out. This new, publicly accessible screening can locate thirty times fainter stars than was previously possible. The astronomers from the Max Planck Institute have now identified a total of 22 million stars that belong to a subclass of the red giant and its properties allow it to determine their distances.

peanut in shell

“The depth of the VISTA-star catalog far exceeds previous work. almost everywhere we can prove all the populations of these stars, only the most obscured regions remain hidden from us,” said Christopher Wegg MPE. “From this star distribution, we can then create a three-dimensional map of the galactic bulge. It is the first time that such a map could be created without the assumption of a model for the shape of the bulge.”

So you could see that the inner region of our galaxy shrouded from the side look like a peanut in its shell, from above, however, such as an elongated bar, added Ortwin Gerhard, Head of the Working Group at MPE.

stellar motions mapped

The second research team, led by Chilean Sergio Vásquez students of the Pontificia Universidad Católica de Chile, chose a different approach to determine the structure of the “bulge.” By comparing the images that were taken at a distance of eleven with the MPG / ESO 2.2-meter telescope, they were able to measure tiny shifts that are caused by the movements of the stars in the “bulge.” These data were combined with away movement measurements of the same star to and from the earth. In this way, the movements of more than 300 stars could be mapped in three dimensions.

“It’s the first time that you could find such a large number of speeds in three dimensions for individual stars from both sides of the bulge,” Vásquez summarizes. “The stars we have observed appear to migrate along the arms of an X-shaped bulges, while their orbits and lead them up and down it even out of the plane of the Milky Way out. All this fits very well with the predictions of current models. “

astronomers believe that the Milky Way was initially pure disk of stars that have formed a flat bar billions of years ago. Whose inner part has curved and accepted the three-dimensional, peanut shape, which can be seen in the new observations. (Red,, 14/09/2013)

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