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Probing the Dark Universe with Weak Lensing

发布时间:2018-06-04 09:04来源:未知 责任编辑:于莹

报告题目:Probing the Dark Universe with Weak Lensing

报 告 人:张骏(上海交通大学,特别研究员)

报告时间:2018年06月07日 16时00分

报告地点:天文楼212报告厅

Abstract: As large instruments continuously bring us huge amount of data in different wave bands, we are facing unprecedented opportunities in exploring various mysteries of our Universe, e.g., dark matter and dark energy, which may lead to exciting leaps in our understanding of fundamental physics. We use large samples of galaxy images to probe the cosmic density evolution through the weak gravitational lensing effect, for the purpose of constraining the physical properties of the dark components. A critical problem in the field of weak lensing is about how to overcome the systematic errors in image processing, a problem that is well known to be difficult, but extremely important for realizing the scientific potential of the weak lensing projects in the planned and ongoing galaxy surveys. We show a series of our progresses in terms of solving these problems model-independently. We report our preliminary results of cosmic shear measurement with the CFHTlens data. As an example, we show that weak lensing can place a tight constraint on the physical property of dark energy. We show that an appropriate definition of void-like point in space can significantly improve the overall signal-to-noise ratio of the void lensing signal, and thereby lead to a much tighter constraint on the equation of state of dark energy.

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