Ithaca New York, Gatra.com Using light from the Big Bang, an international team was being led Cornell University and Lawrence Berkeley National Laboratory from the US Department of Energy began to reveal the material that makes up galaxies. Spacedaily, 17/03. “There is uncertainty about star formation in galaxies that theoretical models cannot predict,” said lead author Stefania Amodeo, Cornell postdoctoral researcher in astronomy at College of Arts and Sciences, who is currently conducting research at the Strasbourg Observatory, France. “With this work, we provide tests to model galaxy formation to understand galaxies and star formation.” Research, “Atacama Cosmological Telescope: Thermodynamic Modeling of Gas in the BOSS CMASS galaxy from Sunyaev-Zel’dovich’s Kinematic and Thermal Measurements,” appeared in Physical Review D. March 15 issue. Proto galaxies are always full of gas and as they cool, they begin to form, said senior author Nick Battaglia, assistant professor of astronomy at Cornell. “If we just do the math back-of-the-envelope, the gas has to turn into a star, “he said.” But it didn’t. “Galaxies are inefficient when they make stars, says Battaglia.” About 10% of the gas – at most – in any galaxy will turn into stars, “he explained,” and we want to know why. “Scientists can now examine their old theoretical and simulation work, by looking at microwave observations with data and applying 1970s-era mathematical equations. They have looked at data from Atacama Cosmology Telescope (ACT) – which observes the cosmic microwave background radiation (CMB) filled with the Big Bang’s static field – and looks for the Sunyaev-Zel’dovich effect. This combination of data allows scientists to map the surrounding material that shows the formation of galaxies in various stages. “How do galaxies form and evolve in our universe?” said Battaglia. “Given the nature of astronomy, we can’t sit and watch galaxies evolve. We use various telescopic photos of galaxies – and each one has its own evolution – and we try to piece together that information. From there, we can extrapolate the formation of the Milky Way.” Effectively, scientists are using the cosmic microwave background – remnants of the Big Bang – as a 14 billion year old backlit screen to find this material around galaxies. “It’s like a watermark on a banknote,” said co-author Emmanuel Schaan, Chamberlain’s postdoctoral fellow at the Lawrence Berkeley National Laboratory. “If it is placed in front of a backlight, the watermark will appear as a shadow. For us, the backlight is the cosmic microwave background. This serves to illuminate the gas from behind, so we can see the shadow as the CMB light moves past it. “Together with Simone Ferraro, a division colleague at Lawrence Berkeley, Schaan led the measurement section of the project.” We made measurements of this galactic material at a distance from the galactic center that has never been done before, “said Battaglia.
Editor: Rohmat Haryadi
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