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2018年第四届 SKA 暑期学校 第一轮通知

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第四届Square Kilometre Array (SKA) 暑期学校将于2018年8月8日-12日在上海天文台举行。本次暑期学校面向全国各高校优秀高年级本科生、研究生招收50名学员以及30名青年学者。此次暑期学校得到了MWA天文台、国家科技部、中国SKA办公室和中国科学院的支持。

国际大科学工程 - 平方公里阵列射电望远镜(SKA)是由全球超过十个国家计划合资建造的、世界最大综合孔径射电望远镜,树立人类认识宇宙和探索自然历程中新的里程碑。SKA即将开建,中国是SKA的创始成员国之一。中国自主建设的21CMA 是世界上最早投入观测运行的用于宇宙再电离探测的专用低频射电望远镜阵列,工作波段在 50 到 200 MHz 范围,可以接收来自宇宙红移 6~27 之间的中性氢辐射。默奇森宽视场阵列(Murchison Widefield Array,MWA)是建于澳大利亚的低频射电望远镜阵列,也是SKA的先导望远镜之一,已经积累了18PB观测数据,提供了未来可以用于SKA 低频数据处理的软件和方法。希望学员们能通过这个暑期学校对SKA低频科学和观测有一个基本的了解,为使用SKA低频先导望远镜数据开展相关科学研究打下基础。

人才培养是保障我国未来实现SKA科学目标的关键。“中国SKA系列暑期学校”旨在培养SKA科学和数据处理人才,面向研究生、本科生、及青年学者。第一、二、三届暑期学校分别于2013、2014、2015年在贵阳、上海和昆明举办。本届暑期学校将集中于SKA低频观测的数据方法和相关科学,在科学内容上将涵盖宇宙再电离时期的中性氢探测、低频连续谱巡天、脉冲星、偏振巡天、星系团、射电暂现源探测等。

暑期学校注册网址: http://ska-summer2018.csp.escience.cn/

研究生或本科生需要在注册时按要求(详见申请资格)提供总共不超过两页的简历及自述,以便组委会根据情况择优资助。

暑期学校具体安排如下:

地点:中国科学院上海天文台

时间:2018年8月8日-12日

授课语言:英语

规模:不超过50名研究生或三、四年级优秀本科生,及不超过30名青年学者

申请资格:

1.天文、物理以及密切相关专业,本科三、四年级、研究生、工作经验小于等于3年的青年学者。

2.因全程英语授课,对英语水平要求较高;英语六级,或托福90分及以上、或雅思6分及以上,优先考虑资助。

3.鼓励学员与讲课老师建立科研合作,优先支持有发表论文或相关科研经历的学员。

费用情况:免注册费,对于本科生或研究生择优资助食宿与交通费,自愿参会学者食宿自理。

报名截止日期:请有意申请的学员在6月30日前完成网上注册。

更多信息及后继信息更新请关注以及上海天文台SKA团组主页:http://202.127.29.4/CRATIV/zh-cn/home.html

重要时间节点:

7月15日:通过邮件通知入选学员【未入选者不再通知】

课程安排

Timetable.pdf

Timetable

Day 1: Wednesday 8th


Day 2: Thursday 9th


Day 3: Friday 10th

 

Day 4: Saturday 11th

Abstracts

Paul:

1. Basics of interferometry

In this talk I will give general introduction to the theory of radio interferometry. We begin with an idealised two element interferometer, explore it's field of view, angular resolution, and sensitivity. We then explore the concept of visibilities, and how a correlator works. I will then move on to talk about multi-element interferometers, how we choose the region of sky we want to see, and how all of the above is dependent on the observing frequency.

2. Calibration and imaging of interferometry data

In this talk we will cover the practical process of calibration of radio visibilities and how images can be made. We will begin with the process of converting measured visibilities into radio images, how these images typically look rather poor, and the process of CLEANing the images to produce nice science quality data. There are many influences that can distort the radio wave-fronts as they are received by an interferometer, and these affects can be mitigated via calibration. I will discuss the process of calibration, the different methods that are available and when they should be employed.

3. Radio transients and variability

The radio sky is not static, with radio sources varying both intrinsically and extrinsically. I will discuss both forms of variability: how we can observe it, what our observations tell us about the sources and the intervening medium. I will also give an overview of radio transients, what we know, and what projects are underway to increase our knowledge. I will show examples of transient and variable radio sources and the projects that are currently underway with the MWA.

Melanie:

Introduction to the MWA

I will present an overview of the Murchison Widefield Array (MWA) telescope and collaboration, including discussion of the instrument capabilities, collaboration structure and science goals.

The Global Radio Astronomy Landscape and the Path to SKA

I will discuss the status of radio astronomy globally and give context to current and future developments in the field. In particular, I will review how current and planned short-term activities provide a pathway towards the Square Kilometre Array.

Steven Tremblay

Title : Pulsar science at low frequencies

Abstract:

In this talk I will introduce the topic of radio pulsars and their properties. Selected topics within the field will be covered with an emphasis on what can be uniquely studied at low frequencies (e.g. dispersion, scintillation, scattering). Observing at these frequencies, however, isn’t without some unique complications, I shall also cover the challenges of observing pulsars with instruments such as the MWA.

Title: The MWA Voltage Capture System

Abstract:

This lecture will give a detailed overview of the high time resolution system employed by the MWA, the so-called voltage capture system (VCS). The unique signal path of VCS observations will be covered, as well as an overview on processing these data. I’ll wrap up with an update on the current state of research being performed with the VCS to give an overview of what science is being done and how it is easiest to contribute.

Title: High time resolution interferometry

Abstract:

Many astrophysical phenomena take place on time-scales shorter than a correlator's averaging time. In order to study these with an interferometer, astronomers need to either consider how the averaging affects their science, or record data using a different method. In this lecture I’ll cover some of these phenomena and discuss how they’re dealt with in practice.

Jack Line:

An Introduction to EoR Science

The epoch of reionisation (EoR) marks the birth of the first stars and galaxies in our Universe. Before them, the Universe was filled with mostly neutral hydrogen; when the first stars switched on, the ionised their surroundings, reionising the hydrogen that formed during recombination. To fully understand the plethora of galaxies and environments we see today, it is important to know when and how the first ionising sources formed. This period of the Universe is incredibly difficult to observe however and remains a challenge to this day. In this lecture I will introduce the science of the EoR, how we might observe it using low-frequency radio interferometers, and some of the challenges we face.

Simulating an Interferometer

The instrumental response of an interferometer is complicated, and has a large effect on any science that comes out of the data. Simulating observations offers a tool to test these instrumental effects individually, and asses their impact on our desired data products. I will start this lecture by building a simple interferometric simulation piece by piece using Python, discussing the computational challenges as I go. I will then introduce the simulation package OSKAR, and compare simulated MWA and SKA_LOW data.

Processing with the RTS and building a sky model

The MWA is an extremely widefield instrument, able to see huge areas of the sky. Traditional calibration techniques that rely on a single calibrator source can often fail, due to so many radio sources being observed at the same time. In this lecture, I will discuss how one might go about building a full sky model to calibrate with, and demonstrate how the software RTS can be used to calibrate, image, and perform foreground source subtraction on MWA data.

Lister:

Lecture 1 Radio Physics

This lecture will cover the basics of radio astronomy, modern radio telescopes and modern spectrometers, including some of the challenges faced at low frequencies. A basic refresher will be given of the main emission physics relevant to low-frequency radio observations, including synchrotron radiation. Examples of low-frequency MWA observations will be given.

Lecture 2 Data Combination

This lecture will cover the theory of combining from multiple radio telescope observations including: combining data taken at different pointing centres into a mosaic; combining interferometer data with zero-spacing data from a large single-dishes; and combining data from telescopes with different resolutions to better sample the uv plane. Practical examples of the benefits of data combination will be given.

Lecture 3 HI science

An introduction to the 21-cm neutral hydrogen line will be given, as well as examples of its usefulness in probing the Universe at redshifts from zero to 20. and possibly beyond. Spectral-line analysis techniques, including calibration and foreground/background subtraction will be discussed.

Steven Tingay:

Maximum science from minimum data processing: MWA applications with MIRIAD

I will outline a number of studies using snapshot MWA data, for surveys and for fast and slow transient investigations. A well-known and simple data processing package, MIRIAD, is well suited for science applications that are based on MWA snapshots. The package has a wide range of functionality (but some significant drawbacks that I will discuss). I will discuss a search for Fast Radio Bursts (FRBs), surveys of the Kepler K2 mission fields, and the potential to use archival MWA to investigate interesting multi-wavelength transient phenomena. I will show some example processing scripts using MIRIAD and, if there is time, run some demonstrations.

Chris:

1. An Introduction To Cosmic Magnetism

Whilst it is commonly accepted that magnetic fields are everywhere in the Universe, their origins remain a mystery. Answering this question — where and when did magnetic fields originate? — is a key science driver for the Square Kilometre Array (SKA). In this talk I will provide an introduction to the topic of cosmic magnetism, discuss the various models of magnetic field origins, and how we probe the magnetised Universe in the radio regime. I will also discuss the underlying physics of the various objects we can use to study the magnetised Universe, and the technique radio astronomers use to do so — namely, polarimetry.

2. Practical Polarimetry with SKA Precursors

Following on from the previous talk where I motivated the topic of cosmic magnetism, this talk will focus on the practical aspects of doing so, using the technique of polarimetry. I will compare and contrast the techniques used by conventional (dish-based) interferometers and aperture arrays, with a particular focus on the Murchison Widefield Array (MWA) and Australia Telescope Compact Array (ATCA). I will also discuss the principal techniques used to extract the underlying physics of radio sources from polarisation data, focusing primarily on Rotation Measure (RM) synthesis and QU-fitting.

3. Cluster Science in the (pre-)SKA Era

In this talk I will review the current state of knowledge in cluster physics, and present some of the cutting-edge results generated by the SKA precursors on the ground in Western Australia — namely the Murchison Widefield Array (MWA) and the Australian SKA Pathfinder (ASKAP). I will highlight a number of specific clusters and what the latest multi-wavelength observations of these objects can tell us about the underlying physics. Finally I will discuss future cluster surveys planned with the MWA, looking forward to the SKA era.

Ben:

Part 1:

How to find/obtain data

So you have completed some MWA observations of your own, or would like to search the archives for a particular target? This tutorial will show you how to find the data you need and download it ready for processing. Students will learn the particular tools they will need and how to access them. We will also cover what has been done to the data in the pre-processing stages e.g. RFI flagging, averaging, phase-centre shifting etc. At the end you will have your data and be on you way to doing science!

Part 2:

Analysis tools and software

Once you have your data in a common format (e.g. uvfits or measurement set) you can use whatever radio-astronomy tools you like for further processing. There is a suite of tools, however, that have been developed specifically with the MWA in mind and I will cover how to access and use these tools in this tutorial. You will learn how to generate a sky model for calibration, calibrate your data, make an image and correct for the primary beam, as well as how to combine multiple images together to cover large areas of sky or integrate deep on a particular target. After this tutorial you will be well-and-truly ready to do your science!

Ben (Saturday AM) - 1 hr

"Global EoR status and updates"

This talk will cover recent developments in detecting the 'global' (or average, all-sky) EoR signal and how the MWA may play a role in this field. After introducing the global signal, I will talk briefly about the recent EDGES result (Bowman et al, 2018) and other experiments aiming to confirm this result. I will then talk about my own project with the MWA, which uses a novel technique whereby we observe the Moon and measure the global temperature of the sky (hidden within which is the global EoR signal), using the Moon as a thermal reference. This experiment may also have implications for future space missions, such as Chang'E and DARE, which are aiming to measure the global EoR signal from the far side of the Moon.

主讲教师:

SOC:

Steven Tingay (Curtin Unversity)

Lister Staveley-Smith (University of Western Australia)

Melanie Johnston-Hollitt (Curtin University)

洪晓瑜(上海天文台)

武向平(国家天文台/上海天文台)

郑倩(上海天文台)

会议联系人:

伍筱聪: wuxc@shao.ac.cn

郑倩:zq@bao.ac.cn

郭铨:guoquan@shao.ac.cn

安涛:antao@shao.ac.cn

中国SKA办公室 主办

中国科学院上海天文台 承办

2018 年 6 月 1日

Prof. Steven Tingay (Curtin University)

Prof. Steven Tingay is Director of the Curtin Institute of Radio Astronomy at Curtin University, Deputy Director of the International Centre for Radio Astronomy Research, and Director of the Murchison Widefield Array (MWA) project. Tingay has authored or co-authored over 100 papers in international refereed journals since 1994 and has attracted over $40m of research funding. His main interests are in radio astronomy, astrophysics and radio astronomy instrumentation. Over the last ten years, Tingay has led the development of software and hardware that has upgraded Australia's suite of radio telescope facilities. He currently leads the MWA project, a $50m low-frequency radio telescope currently under construction in the remote Murchison region of Western Australia. The MWA is a Precursor for the Square Kilometre Array (SKA). Tingay has been an active contributor to the international SKA project for the last decade.

Prof. Lister Staveley-Smith (UWA)

Professor Lister Staveley-Smith is Science Director (UWA) within the International Centre for Radio Astronomy Research (ICRAR). His research is oriented towards frontline radio astronomical observations with world-class facilities, and preparing the path for future telescopes such as the Square Kilometre Array (SKA) and its precursors, the ASKAP and MWA telescopes. ASKAP and MWA will be built in Western Australia which is also one of the two sites for the SKA.

Prof. Melanie Johnston-Hollitt

Prof. Johnston-Hollitt's primary research interests are cosmic magnetism and observations of galaxy clusters, primarily through the use of radio telescopes. She has authored over 200 publications, and supervised over 30 research students (Honours, MSc and PhD). She has served on the Editorial Board of Publications of the Astronomical Society of Australia since January 2015, commencing a 3-year term as Editor-in-Chief from January . She is known for having worked on the design, construction, and international governance of several major radio telescopes including the Low Frequency Array (LOFAR), the Murchison Widefield Array (MWA) and the upcoming Square Kilometre Array (SKA). She is currently Director of the Murchison Widefield Array and a full Professor at the Curtin Institute of Radio Astronomy at Curtin University and the International Centre for Radio Astronomy Research.

Dr Ben McKinley

Dr Ben McKinley is a Research Fellow at Curtin University in Australia. His current research is focused on using the Murchison Widefield Array (MWA) telescope to measure the global, redshifted 21-cm signal from the Epoch of Reionisation. Other research interests include studying the closest radio galaxies with the MWA and data from telescopes covering the full electromagnetic spectrum. He is also a member of the SKA Cosmic Dawn and Epoch of Reionisation Science Working Group and involved in testing of the most recent SKA prototype deployed at the Murchison Radio-astronomy Observatory in Western Australia (future site of the SKA-low). Dr McKinley is a member of ASTRO-3D, the Centre of Excellence for All-sky Astrophysics in 3 Dimensions, which is a new Australian organisation that aims to understand the evolution of the matter, elements and light in the Universe from the Big Bang to the present day.

Dr. Paul Hancock (Curtin University)

He is an Early Career Research Fellow currently at Curtin University. He obtained my PhD at the University of Sydney, where he worked on the Australia Telescope 20GHz (AT20G) survey. he then continued to work as a Super Science Fellow in radio transients at USYD where he helped to create the Variable And Slow Transients (VAST) prototype pipeline, including the source finding algorithm Aegean. his interests are in radio transients including: supernovae, gamma-ray bursts, and tidal disruption events. He leads two projects that use the Murchison Wide-field Array (MWA). The first project uses the scintillation of extragalactic radio sources to trace the turbulent structure of gas within the Milky Way. The second project uses the MWA to search for radio emission from fireballs as they burn a path through our atmosphere.

Dr. Steven Tremblay (Curtin University)

Dr Steven Tremblay is based at Curtin University in Perth and works on Fast Radio Transients in CAASTRO's "Dynamic Universe" theme.

Dr. Jack Line (University of Melbourne)

Dr. Christopher Riseley (CSIRO)

Dr. Christopher Riseley is an OCE post-doctoral fellow, specialising in low-frequency radio astronomy, galaxy clusters and polarimetry. He is based in CASS's still rapidly expanding Perth office, and recently obtained his PhD from the University of Southampton in the UK. His thesis focused on detecting radio emission from galaxy clusters using SKA pathfinder and precursor radio telescopes, and developing low-frequency source catalogs from sensitive widefield radio images.

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