12月23日（周二）
报 告 人：贺昊宁（Department of Physics & Astronomy, UCLA）
报告题目：The possible origins of the observed high-energy neutrinos and Ultra-High-Energy Cosmic Rays.
报告摘要：The IceCube Neutrino observatory at the South pole in Antarctica reported a series of detection in the past few years. Exciting new researches are opening a new window for exploring our universe. We study the high energy neutrinos from the possible astrophysical source gamma-ray burst, hypernova and ultra-luminous infrared galaxy, and suggest that the IceCube observed TeV-PeV non-atmospheric neutrinos may originate from two or more than two groups of source. Methods to distinguish between these proposed origins are discussed. The Telescope Array collaboration has reported a hotspot, a cluster of 19 cosmic ray events with energies above 57 EeV in a circle of 20 degree radius. We explore the hypothesis that the hotspot could originate from a single source. By considering the energy dependent deflections that are expected to affect arrival directions of cosmic rays propagating in cosmic magnetic fields, we identify the nearby starburst galaxy M82 and the bright nearby blazar Mrk 180 as two likely candidates. If the hotspot events originate from M82, these cosmic rays are likely to be light nuclei. The prospects of discriminating between the candidate sources with current and future spectral data have been discussed.
---------------------------------------------------
12月24日（周三）
报 告 人：董辉（IAA-CSIC）
报告题目：Unveiling the Massive Stars in the Galactic Centre
报告摘要：Because of the proximity, the Galactic Centre is a unique lab for studies of the interplay between stars, ISM and super massive black holes in galactic nuclei. The central 200 pc of the Galactic Centre includes 4x10^7 molecular clouds and has a star formation rate of ~0.03 M/yr. Three young, massive and compact star clusters were found and includes around 100 massive stars, which strongly shape the nearby ISM. However, the massive stars beyond the clusters are still unknown. A complete census of these `field' massive stars have an important impact on our understanding of several fundamental astrophysical questions, such as 1) how molecular clouds form stars in this extreme environments, 2) initial massive function and 3) the stellar evolution models for massive stars in high metallicity environment. I will present our effort during these years to identify massive stars in the Galactic Centre and study their properties and origin. Our results show that massive stars pervade the Galactic Centre and they partly formed in situ and partly were ejected from the three clusters.
----------------------------------------------------
12月25日（周四）
报 告 人：马寅哲（Jodrell Bank Center for astrophysics, University of Manchester）
报告题目：Detection of the missing baryons with Planck data
报告摘要：Previous studies of galaxy formation have shown that only less than one thirds of the baryons are in compact objects, while the majority of them are missing. Numerical simulation shows that the missing baryons are in a state of diffuse plasma with temperature 10^5 to 10^7 Kevlin, which is hard to be detected by X-ray observations. We will present three studies that coherently detect the missing baryons. The first is the cross-correlation between the kinetic Sunyaev-Zeldovich maps from Planck with the linear reconstructed velocity field. We find significance (4.6 sigma) detection of the peculiar motion of gas on Mpc scales. Further studies show that this bulk motion indicates that the concentration of gas constitutes a fraction of f_b=0.8, which indicates that all baryons are detected with the Planck kSZ maps. Second, we cross-correlate the thermal Sunyaev- Zeldovich from Planck maps with gravitational lensing from the Canada France Hawaii Lensing Survey (CFHTLenS) and constrain the diffuse baryon component with the various pressure profile. We find that the 1 and 2 halo terms detected at 3.96$\sigma$ and 3.67$\sigma$ confidence level (CL) respectively. The effective virial temperature of the isothermal gas is found to be in the range 7 *10^{5}--3*10^{8} K. The third test is to stack the pairs of luminous red galaxies, then we can place a constraint on the temperature of the filament in between the dark matter halos.
时 间：中午11:30
地 点：202会议室
欢迎各位老师、同学参加！
南京大学天文与空间科学学院
