SHAO Astrophysics Colloquia

Title: Binary population synthesis and the formation of binary-related objects

Speaker: Zhanwen Han (Yunnan Observatories)

Time: 3 PM, May 25th (Thursday)

Location: Lecture Hall, 3rd floor

Abstract: Binary population synthesis (BPS) is an algorithm to evolve a large number of stars (including binaries), in order to investigate statistical properties of binary-related objects and check their evolutionary scenarios. We have developed the BPS theory and studied the formation of many binary-related objects, including hot subdwarf stars, progenitors of type Ia supernovae, double white dwarfs etc. The BPS also plays a role in the study of sources of gravitational wave radiation. Furthermore, the BPS model of binary-related objects can be applied to evolutionary population synthesis (EPS) studies of galaxies, showing that binary interactions are crucial to our understanding of spectral energy distribution (SED) at short wavelengths for old stellar populations.

Galaxy seminar

Title: Machine learning of LAMOST DR1 archive

Time: 10:30 am May 24th

Place: room 1715

Speaker: Dr. Petr Sokda (Astronomical Institute of the Czech Academy of Sciences)

Abstract： The practical work with technology of Virtual observatory will be

presented on several practical exercises focused namely on analysis and

machine learning of LAMOST DR1 archive.

Group meetings

Black hole Accretion and High-energy Astrophysics /Black Hole Feedback and Cosmic Ray Astrophysics Seminar

Location: 1608

Time: 9:30-11:30, Friday(May 26th)

Speaker: Bin Liu

Title:  The Kozai-Lidov Mechanism in Hydrodynamical Disks. III. Effects of Disk Mass and Self-gravity

http://adsabs.harvard.edu/abs/2015ApJ...813..105F

Speaker: Yaping Li

Title: Star Formation in Simulated Galaxies: Understanding the Transition to Quiescence at $3\times10^{10}$ M$_\odot$

http://adsabs.harvard.edu/abs/2017arXiv170503173T

Galactic Dynamics Group Journal Club

Time: May. 25th (Thursday) 9:45 AM

Location: Room 1608

Title: SDSS-IV MaNGA - The spatially resolved nitrogen abundance gradients and transition from star formation to quiescence

Speaker: Man I Lam

References:

http://adsabs.harvard.edu/abs/2017MNRAS.466.2570B 

http://adsabs.harvard.edu/abs/2017arXiv170303813B 

Abstract:

Large galaxy surveys support that galaxies may quench at least two quenching pathway, the environment-dependent and mass-dependent ways. In the first paper, the authors constructed the large sample of ~600 galaxies, and further discussed the two types of low ionization emission-line regions (LIERs) in local galaxies. Central LIERs (cLIERs) are late-type galaxies with being slowly quenched inside-out. Extended LIERs (eLIERs) are passive galaxies with cold gas component, which may be the acrrection process from external.

Metals are direct products of stellar nucleosynthesis, which is a powerful tool to understand star formation and gas inflow/outflow process in galaxies. In the second paper, the authors discussed the oxygen abundance and nitrogen gradient by using the strong line ratio diagnostics. For massive galaxies, the oxygen abundance of central regions has already in a equilibrium phase, while the nitrogen abundance is still increasing. For less massive galaxies, both oxygen and nitrogen abundances are relatively flatten.