Monday, June 18, 2012

Dark matter is back, News Brief of Astronomy

Recent reports of the desertion of the dark matter may be greatly exaggerated, according to a new article by researchers at the Institute for Advanced Study (IAS). A group of astronomers using ³ ESO telescopes announced a-new-study-finds-no-matter-dark-in-the-vecindade in April a surprising lack of dark matter in the galaxy in the vicinity of the Solar System.
The team, led by Christian Moni Bidin from the University of Conception in Chile, Map ³ s more than 400 stars near the Sun, covering a region of approximately 13,000 year n ± os-light radius.His report identifies a number of ³ material coincidÃa thus owed may be observed directly: stars, gas and polvoâ € | but not dark matter. â € œNuestros comfortable calculations show that Provision must have been clear in our measurements. But just  was not there!  €, sir allergic ³ ± Bidin. But other teams were not sure about some cases in which the ESO team habÃa based their calculations comfortable. Jo Bovy Researchers and Scott Tremaine of Study Institute Advanced in Princeton, New Jersey, presented a study claiming that the results published by Moni Biden and his colleagues are â € œincorrectosâ €, â € based on an invasive œsupuesto € lidoâ movements of the stars in â € "and over-the plane of the galaxy. â € œThe biggest mistake is assuming that the average velocity azimuth (or rotation) of its population screening is independent of the radius cilÃndrico galactocà © ntrico in all aspectosâ € , sir alan ± Bovy and Tremaine in their study. â € œThis suposicià ³ n is supported by the data, which in turn implies s ³ which the circular velocity is independent of the radius in the plane medioâ €. The researchers suggest that the stars in the local neighborhood move more s slower than the speed assumed mean by the team of ESO, in a behavior known as drift Asima © Trica. This difference varÃa with the position n of a comfortable second mule in the galaxy, but, according to n Bovy and Tremaine, â € œThis variation cannot be measured for the sample [used by the team of Moni Biden], since the data do not cover a range € grandeâ enough. When the researchers took the observations of IAS Moni Biden but replaced the assumptions â € œinvà € lidasâ ESO team on the motion of stars within and above the galactic plane with its own assumptions â € œbasados in datosâ €, ³ dark matter reappeared. â € œNuestro Public Access lysis shows that the dark matter density measured locally is consistent with the extrapolated halo models restricted to distances galactocà © ntricasâ €, report Bovy and Tremaine. As such, the dark matter thought ³ I was beyond is there. (Sega º n comfortable calculations.) Y, year ± aden the two researchers, Not only what is there, but that is in amounts more s dense than average, at least in the regions around the Sun â € œThe density of the halo in the Sun, which is the amount of the experiments deteccià ³ n direct dark matter is likely to be higher due to gravity concentrated by diskA €, sir ± alan Bovy and Tremaine. When you take into account the comfortable calculations of stellar velocities based on data and motion of matter halo not Baria ³ nica is thought to involve the VÃa Là CTEA , found that â € œthe density of dark matter in the midplane is superior € | in approximately 20% â €. So I instead of a â € € œserio hits the existence of matter dark, the results of Bovy and Tremaine â € "such as Moni handle Biden and his team-Not only can you have found dark matter,  but give us 20% more.

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