学术报告第196期：21-cm Intensity Mapping: foreground removal and stacking results

主讲人 (Speaker): 

马寅哲

主讲人单位 (Speaker's Institute): 

南非夸祖鲁·纳塔尔大学天文学与宇宙学研究中心

邀请人 (Invited by): 

张乐

时间 (Time): 

星期二, 2020/12/22 - 15:00 to 16:30

地点 (Location): 

珠海校区天琴中心2316会议室

摘要 (Abstract): 

       21-cm intensity mapping is a novel probe of cosmic acceleration and structure formation at low redshifts but is stiffly contaminated by the foregrounds. Thus, the indispensable technique to obtain a cleaned 21-cm map is to extract the foreground and reconstruct the images of the 21-cm signal. In this talk, I present two methods to extract the foreground and compare their performance against the simulated inputs. I then took the foreground-cleaned Parkes radio telescope data and stacked the 2dF galaxies on the data, and obtain, for the first time, the stacked 21-cm emission signal of neutral hydrogen from the stacked dark matter halos. I will then describe its astrophysical implication.

       The last part of the talk, I will briefly present the initiative of South Africa-China collaboration in astronomy, and how this collaboration can push the measurement of 21-cm cosmology to the exquisite limit.

主讲人简介 (Speaker's CV): 

马寅哲：南非夸祖鲁·纳塔尔大学天文学与宇宙学研究中心副教授，于2011年在英国剑桥大学取得博士学位，先后在加拿大英属哥伦比亚大学、英国曼彻斯特大学做博士后和助理研究员。马寅哲副教授在宇宙微波背景辐射、星系速度场、临近场宇宙学，以及射电宇宙学等领域取得了一些独立的、国际认可的学术贡献；正在主持中国—南非双边合作项目“宇宙学和大型巡天”，主持中国和南非双边中心以及金砖国家21-厘米射电天文项目。