SHAO Astrophysics Colloquia
Title: Not-so-simple stellar populations in nearby, resolved massive star clusters
Speaker: Richard de Grijs (KIAA/Peking)
Time: 1:30 PM, January 19 (Thursday)
Location: Lecture Hall, 3rd floor
Abstract:
Until about a decade ago, star clusters were considered "simple" stellar populations: all stars in a cluster were thought to have similar ages and the same metallicity. Only the individual stellar masses were thought to vary, in essence conforming to a "universal" initial mass function. Over the past decade, this situation has changed dramatically. I will discuss my group's recent progress in this context, with particular emphasis on the properties and the alleged presence of multiple populations in Local Group star clusters across the full age range. Our most recent results imply a reverse paradigm shift, back to the old simple stellar population picture for at least some intermediate- age (~2 Gyr-old) star clusters, which opens up exciting avenues for future research efforts.
Title: "The Science of Heaven" documentary screening
Speaker: Richard de Grijs (KIAA, Beijing)
Time & Place: Monday, 3:00pm, January 16th, 3rd floor Lecture Hall, SHAO
Abstract: For thousands of years, Chinese astronomers have watched the sky by day and at night, looking for -- as the Yi Jing (the Book of Changes) puts it -- “symbols from above, which show good or bad fortune”. But in the last few decades China has been catching up. The government’s Five Year Plan states that China must push forward its exploration of planets, asteroids and the Sun. If this happens according to the country’s usual growth rate, much can be expected from “The Science of Heaven” over the next decades. In this documentary we explore the Chinese history of the “Science of Heaven”, and we establish links to the most recent Chinese explorations in astronomy and astrophysics. We visit observatories in remote areas in China, we witness the final construction phase of the world’s largest radio telescope in Guizhou and we might end up on the Moon with the Chinese Lunar Program. This documentary was originally conceived by Richard de Grijs (Kavli Institute for Astronomy and Astrophysics, Peking University) and Ziping Zhang (Beijing Planetarium). They commissioned René Seegers as director/producer and secured funding from the National Natural Science Foundation of China (NSFC). The documentary is targeted at a general audience.
Galaxy Seminar
Location: 1714
Time: 10:30, Jan.18 (Wednesday)
Title: Intermediate-Width Emission Lines in Active Galactic Nuclei
Speaker: Zhenzhen Li
Contact: Jian Fu, Fangting Yuan, Chunyan Jiang, Zhaoyu Li, Ting Xiao
Abstract: It is generally accepted that emission lines of active galactic nuclei arise from two well-separated regions: the broad emission line region (BELR) and the narrow emission line region (NELR). This separation of emission-line regions yields an obviousgap between these two regions. Some researchers suggested that AGNs also contain intermediate-width emission line regions (IELRs) producing intermediate-width emission lines (IELs). A consensus, however, is yet to be arrived at due to the lack of convincing evidence for their detection. Recently, we detected prominent IELs in a partially obscured quasar OI 287, where the conventional BELs are heavily suppressed by extinction. The clearly detected IELs provide strong evidence for the existence of the IELR, which has been in debate for two decades. Also, we found that the IELs in normal quasar are usually very weak, which cannot be detected if the BELR is not obscured. Finally, I will report the physical reason for explaining the observed suppression of the gap between the BELR and the NELR.
References :
http://adsabs.harvard.edu/abs/1993ApJ...415..563W
http://adsabs.harvard.edu/abs/1993ApJ...404L..51N
http://adsabs.harvard.edu/abs/2015ApJ...812...99L
http://adsabs.harvard.edu/abs/2016ApJ...831...68A
Group meetings
Black hole Accretion and High-energy Astrophysics /Black Hole Feedback and Cosmic Ray Astrophysics Seminar
Location: 1608
Time: 14:00-16:00, Wednesday (Jan.18th)
Speaker: Bin Liu
Title: Spin-Orbit Misalignment of Merging Black Hole Binaries: Effects from External Perturber
Speaker: Xiaodong Duan
Title: AGN Heating in Simulated Cool-Core Clusters
http://adsabs.harvard.edu/abs/2016arXiv161105455L
Location: 1608
Time: 14:00-16:00, Wednesday (Jan. 18)
Galactic Dynamics Group Journal Club
Time & Location: 9:30 AM, January 19 (Thursday),Room 1608
Title: Intermediate-Width Emission Lines in Active Galactic Nuclei
Speaker: Zhenzhen Li
Abstract: It is generally accepted that emission lines of active galactic nuclei arise from two well-separated regions: the broad emission line region (BELR) and the narrow emission line region (NELR). This separation of emission-line regions yields an obviousgap between these two regions. Some researchers suggested that AGNs also contain intermediate-width emission line regions (IELRs) producing intermediate-width emission lines (IELs). A consensus, however, is yet to be arrived at due to the lack of convincing evidence for their detection. Recently, we detected prominent IELs in a partially obscured quasar OI 287, where the conventional BELs are heavily suppressed by extinction. The clearly detected IELs provide strong evidence for the existence of the IELR, which has been in debate for two decades. Also, we found that the IELs in normal quasar are usually very weak, which cannot be detected if the BELR is not obscured. Finally, I will report the physical reason for explaining the observed suppression of the gap between the BELR and the NELR.
References :
http://adsabs.harvard.edu/abs/1993ApJ...415..563W
http://adsabs.harvard.edu/abs/1993ApJ...404L..51N
http://adsabs.harvard.edu/abs/2015ApJ...812...99L
http://adsabs.harvard.edu/abs/2016ApJ...831...68A
