报告题目: The Cosmology Large Angular Scale Surveyor (CLASS)

　　报 告 人: Lingzhen Zeng(曾令震)(Harvard-Smithsonian Center for Astrophysics)

　　B.A. in astronomy, University of Science and Technology, China (2005);

　　Ph.D. in astronomy, Johns Hopkins University (2012);

　　Scientist at Harvard-Smithsonian Center for Astrophysics (2012-).

　　Research specialties: millimeter/submillimeter instrumentation, cosmology and interstellar medium.

　　报告摘要: There is a fundamental question in cosmology, “Did inflation really happen?” Inflation posits that the universe grew from quantum fluctuations of the vacuum driven by negative pressure energy to expand exponentially to astronomical scales. The simplest (and therefore most compelling) versions of inflation produce a stochastic background of gravitational waves whose amplitude depends only on the energy scale at which inflation occurred. The gravitational waves imprint a polarization pattern on the CMB (B-mode polarization), that then provides a direct way to measure the energy scale of inflation. In this talk, I will present the Cosmology Large Angular Scale Surveyor (CLASS) project. It is an experiment with an unprecedented ability to detect the B-mode polarization to the level of r (the tensor to scalar ratio) ≤ 0.01. It consists of 4 ground-based wide-field polarimeters, operating at 40, 90 and 150 GHz. CLASS will measure the large angular scale CMB polarization signature by observing ~65% of the sky above 45 degrees elevation from the Cerro Toco in the Atacama desert of northern Chile, 5180 meters above sea level.

　　报告时间: 11月25日(星期一) 上午10:30

　　报告地点: 紫台办公大楼619会议室

　　联 系 人：单文磊83332229

　　欢迎大家积极参加！ 

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