Events

Unknown Treasure Trove of Planets Found Hiding in Dust

Until recently, protoplanetary disks were believed to be smooth, like pancake-like objects. The results from this study show that some disks are more like doughnuts with holes, but even more often appear as a series of rings. The rings are likely carved by planets that are otherwise invisible to us. Image: Feng Long

Undefined

Towards a Full MHD Jet Model of Spinning Black Holes

The Event Horizon Telescope has achieved resolution of ~ 60 microseconds on 1.3 mm wavelength, which has been used for resolving the horizon-scale structure of black holes (BHs) nearby, including Sgr A* and M87. Motivated by the coming high-resolution observations, we aim to develop a full MHD jet model of spinning BHs. In this model, electromagnetic fields and fluid motion are governed by the Grad-Shafranov equation and the Bernoulli equation, respectively.

A New X-Ray Selected Galaxy Cluster Sample from the ROSAT All-Sky Survey

Some indications for tension have long been identified between cosmological constraints obtained from galaxy clusters and primary cosmic microwave background (CMB) measurements. Typically, assuming the matter density and fluctuations, as parameterized with Omega_m and sigma_8, estimated from CMB measurements, many more clusters are expected than those actually observed. This has been reinforced recently by the Planck collaboration.

Recent developments in the modelling of the solar chromosphere

The chromosphere is arguably the most difficult and least understood domain of solar physics. All at once it represents the transition from optically thick to thin radiation escape, from gas-pressure domination to magnetic-pressure domination, from neutral to ionised state, from MHD to plasma physics, and from near-equilibrium ("LTE") to non-equilibrium conditions.

Data Oriented GRB Research and the Gravitational Wave GRBs

 In this talk, I will briefly discuss our recent data oriented research works in GRB field. I will first review our fully automatic GRB data analyzing system. I will then talk several case studies that directly utilized the results from our system. In particular, I will focus on prompt emission data of the gravitational wave GRB 170817A and discuss our current understanding of this first NS-NS merger event,  including its event rates, ejecta topology, radiation mechanism and what can learn from the 1.7 s time delay between the GRB and the gravitational signal. 

Speaker: 
Binbin Zhang
Nanjing University
Place: 
KIAA-PKU Auditorium

Galaxy formation in the first billion years of the Universe: progress, big questions, and future

Understanding the formation of galaxies in the first billion years of the Universe is one of the key questions in galaxy evolution as well as cosmic reionization. Despite the remarkable progress on finding large samples of z>5 galaxies in the past few years, many big questions still remain unsolved.

Speaker: 
Xiangcheng Ma
University of California, Berkeley
Place: 
KIAA-PKU Auditorium