天文現象及活動

物理系學生會議：磁場方向與恆星形成率之間的關聯

Talk:- The Link between Magnetic-Field Orientations and Star Formation Rates

Star formation rates (SFR) is a key component in modern star-formation models, which mainly involve gravity, turbulence and, in some cases, magnetic fields (B-fields). But the connection between B-fields and SFR has never been observed. A comparison between the survey of SFR and a study of cloud-field alignment – which revealed a bimodal (parallel or perpendicular) alignment – shows that clouds with lower SFR per solar mass are tend to perpendicular to the B-fields. This might be an evidence of B-fields being a primary regulator of SFR. We used B-fields data from starlight method and 353 GHz dust thermal emission, which comes from by Planck mission’s all sky survey.　
　
時間：2017.05.20(六) 15:30 ~ 15:45
地點：香港中文大學 科學館LT4
講者：GU Qilao
語言：英語

#131

此活動由香港中文大學物理系主辦。

物理系學生會議：探測中等質量黑洞的可能途徑 – 經重力透鏡效應的重力波

Talk:- A Possible Way to Probe Intermediate Mass Black Hole – Gravitational Lensing of Gravitational Wave

Existence of intermediate mass black hole is a mystery in astronomy. Theoretically it should exist, but it hasn’t been confirmed by observation yet. Since intermediate mass black hole is a possible candidate of gravitational lens, its lensing effect on gravitational wave in diffraction limit could be a direct observational evidence. Basic analysis shows the lensing effect is observable within LIGO detectability. Serious Bayesian analysis is ongoing to investigate under what circumstances we can confirm that the signal indicates an intermediate mass black hole.　
　
時間：2017.05.20(六) 15:15 ~ 15:30
地點：香港中文大學 科學館LT4
講者：Lai Kwun Hang 及 Otto Hannuksela
語言：英語

#131

此活動由香港中文大學物理系主辦。

物理系學生會議：磁場方向在絲狀雲中恆星形成率的影響

Talk:- The Effect of Magnetic Field Orientation on Star Formation Rate in Filament Clouds

With the rapid growth of computational power, numerical simulation has become more and more important in astrophysical researches in the last few decades. In this presentation, we will briefly introduce the simulation we are adopting in our group, as well as one of the currently undergoing simulation projects, aiming to reveal the effect of magnetic field orientation and other effects on star formation rate in filament clouds. The importance of magnetic field orientation in star formation has been gradually realised in the recent decades. However, the effect of different orientations on star formation rate in particular types of filaments is still yet to be understood, which will be the central topic of the project.　
　
時間：2017.05.20(六) 15:45 ~ 16:00
地點：香港中文大學 科學館LT4
講者：GUO Zitan
語言：英語

#131

此活動由香港中文大學物理系主辦。

物理系學生會議：具有限化學勢的大質量中微子於宇宙擴張史及大尺度結構的影響

Talk:- Influence of Massive Neutrinos with a Finite Chemical Potential on the Cosmic Expansion History and Large Scale Structure

Due to their high abundance, massive cosmic neutrinos would have a significant influence on cosmology, especially in terms of large scale structure. Ever since the discovery of neutrino oscillation, which confirmed that neutrinos have finite masses, many efforts have been made to constrain neutrino masses from cosmology. However, none of them has considered the possibility of a finite chemical potential, if the neutrinos are not majorana fermions. The work would be the first one to analyse the combined effect of masses and chemical potentials of neutrinos on matter power spectrum of large scale structure, through two physical processes, their influence on the cosmic expansion history, and the neutrino free-streaming. The result would serve as a correction to the constraints of neutrino masses from large scale structure.　
　
時間：2017.05.20(六) 16:15
地點：香港中文大學 科學館LT4
講者：
　　●Zhichao Zeng
　　●Shek Yeung
　　●Ming Chung Chu
語言：英語

#131

此活動由香港中文大學物理系主辦。

物理系學生會議：教科書編成《NSS Physics Insight – A Short Introduction to Special Relativity》

Talk:- NSS Physics Insight – A Short Introduction to Special Relativity

We have developed a textbook (NSS Physics Insight – A short introduction to Special Relativity) teaching Secondary Senior Form students Special Relativity. There are 6 major chapters about Special Relativity included, together with 4 supplementary chapters providing required mathematics skills, like limits and differentiation, integration, vectors and matrices, for students to tackle Special Relativity problems. Time dilation, length contraction, Lorentz transformation and the application of Spacetime diagrams are included in the textbook. We adopted the example-based approach in the textbook, that is, we provided examples for students to follow and some follow-up challenges for them to apply what they have learnt. To arouse interest of the readers, we also made use of comics and dialogues to exemplify the physics concepts and theories. Problem sets are available at the end of each chapter, in which students can test their understanding. It is notable that most of the problems in the textbook were originally designed, with extra features like problems are implemented based on novels, increasing difficulty of problems of similar situations. A full solution manual is also available for students to check their answers and steps. Supplementary notes and explanation are also provided in the manual.　
　
時間：2017.05.20(六) 16:00 ~ 16:15
地點：香港中文大學 科學館LT4
講者：Li Ka Yue Alvin 及 Pang Yiu Yung
語言：英語

#131

此活動由香港中文大學物理系主辦。

Plenary talks:- Twinkle twinkle dirty stars, how I wonder how you die

In the standard theory of stellar evolution, stars die and become white dwarfs, neutron stars, or black holes, depending on their masses. Many stars go through spectacular explosion and become supernovae before their final deaths. However, this standard theory ignores possible admixture of dark matter – invisible matter that interact only gravitationally and maybe weakly – and their effects on the stellar structure, even though dark matter is known to be the dominant form of matter in the universe. the speaker will briefly introduce work done in CUHK investigating dark matter admixed stars, particularly how they die!　
　
時間：2017.05.20(六) 09:30 ~ 10:00
地點：香港中文大學 科學館LT4
講者：朱明中 教授
語言：英語

#131

此活動由香港中文大學物理系主辦。

Invited talks:- Multi-scale Magnetic Field Orientation and its Observation

The role of magnetic fields is an important problem in star formation. We investigate the orientations of magnetic fields at different spatial scales by comparing the optical data with the single dish and interferometer data. We found that the magnetic field orientations are well correlated from 300 pc to 0.1-1 pc, and show a bimodal distribution when deep into ~0.01pc. In order to verify this result and further investigate the field morphology problem, our group is constructing a polarimeter, APol which will allow us to do experiment and get our own data.　
　
時間：2017.05.20(六) 11:15 ~ 11:40
地點：香港中文大學 科學館LT4
講者：Yapeng Zhang
語言：英語

#131

此活動由香港中文大學物理系主辦。

8時33分

不少人有些錯覺，認為天文學內容高深，研究的都是些遙不可及的事物，其實最初人們留意日月的位置變化和出沒規律，為的只是農耕和預防河流氾濫等生活需要，但由此發展出日、月、年的時間觀念，成為人類生活的一個重要組成部份，與我們生活息息相關。本課程會運用生活化的例子，從星座和以星星辨認方向等開始講解天文學的內容，又會從近年傳媒熱衷報導的藍月、流星雨等帶領參加者正確認識各種天文現象。

◎理論課
●觀星禮儀、講解天文學與氣象學的分別，認識星座與黃道12星座
時間：2017.05.19(五) 19:00 ~ 22:00
●認識太陽系和太陽系各成員最新的科學發現
時間：2017.05.26(五) 19:00 ~ 22:00
●認識各種天文現象和解釋其成因
時間：2017.06.09(五) 19:00 ~ 22:00
●深空天體、認識人類在宇宙的位置
時間：2017.06.16(五) 19:00 ~ 22:00
●天文望遠鏡和各種天文儀器的介紹
時間：2017.06.23(五) 19:00 ~ 22:00
●太空探險、地外生命的探索
時間：2017.06.30(五) 19:00 ~ 22:00
地點：土瓜灣 馬頭涌50號 工人俱樂部

◎實習課
日期：2017.06.02(五)
時間：(待定)
地點：(待定)

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【訊息由張詠倫提供】

此活動由工聯會業餘進修中心主辦。

日期：2017.05.19(五) 19:00 ~ 2017.05.20(六) 16:45
地點：創興水上活動中心
集合：2017.05.19(五) 19:00 @西貢鄧肇堅運動場上車
名額：48

收費活動，參加者必須報名，2017.03.24 截止，2017.03.31 抽籤選拔
2017.04.24 ~ 2017.05.19 候補報名

#83

此活動由康樂及文化事務署主辦。