What is AMiBA
AMiBA
(Array for
Microwave
Background
Anisotropy),
a microwave telescope located at Mauna Loa Observatory (MLO),
is designed for measuring the first light of our universe.
AMiBA
AMiBA and its science
AMiBA was constructed by the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), with a couple of collaborators, including the Department of Physics of National Taiwan University (NTU). Routine scientific operations occurred from 2007 to 2008 (primary) and from 2011 to 2014 (upgraded).
The purpose of AMiBA was to precisely measure the photons of the cosmic microwave background (CMB), which were emitted from the early universe and warmed up by galaxy clusters. Such photons provided insights to researchers about how our universe grew up and what it looks like on a large scale today. We used AMiBA data to identify the density and temperature of the hot gas in those clusters, which traces the underlying dark matter distribution.
什麼是阿米巴？
阿米巴陣列（AMiBA，
Array for
Microwave
Background
Anisotropy）
坐落於美國夏威夷州毛納羅亞觀測站，
是一座用來偵測來自宇宙初生之光的微波望遠鏡干涉陣列。
AMiBA
阿米巴及其科學目標
阿米巴陣列望遠鏡是由中央研究院天文及天文物理研究所，以及國立台灣大學物理系共同設計建造， 並與國際上許多研究單位合作運轉。初代機於 2007 年開始投入科學觀測，2011 年進行設備升級， 最終於 2014 年結束運轉並退役。
阿米巴陣列的科學目標是精準地量測來自宇宙早期，並且被星系團局部加熱的宇宙微波背景輻射。 這些光線能夠揭露宇宙是如何成長，直到變成今日所見，特別是在大尺度上的樣貌。 我們能夠利用阿米巴陣列的觀測資料，來計算遠方星系團中熱氣體的密度和溫度， 並且由此來了解所謂「暗物質」在重力系統中的分布。
What we did during the operation
Based in downtown Hilo, we headed to the AMiBA site once a week for a three- or four-night observation. Measurement started at around 6 pm and roughly took 12 hours.
Works
駐站觀測時都在做什麼呢？
我們每個禮拜都會從夏威夷大島的希洛鎮前往阿米巴基地，每一次連續值勤三或四個夜晚，
而每天的觀測從下午六點開始，到隔天上午六點左右結束。
Works
Monitoring Weather
Water vapor in the atmosphere would significantly absorb microwaves; therefore, clear weather with low humidity (typically below 40%) was required for our observation. We wouldn't uncover the shield of the observatory if the weather condition was bad, such as cloudy or rainy.
Preparing Observation
To avoid thermal deformations during observation, we opened the shield of the observatory and lifted the platform of detectors to the standby position to let the machine reach thermal equilibrium with the environment. Then we checked the status of all receivers and offline the bad ones.
Measuring CMB Signals
Following the observational plan, we sent commands to manipulate the machine. There were two equal-time patches in a detection, one directly measuring signals from a galaxy cluster and another one measuring signals from a blank sky beside the galaxy cluster.
Collecting Calibration Date
Calibrators played an important role as standard candles that set references to calibrate the strength and phase of the signals. We used the planets in the solar system as the calibrators because they were bright enough, and their real-time properties were well-known.
Writing Daily Reports
The daily report recorded the weather conditions, the status of the instruments, and the real observational schedule. It also demonstrated the condition of all baselines of the interferometer as simple diagrams. We posted the report on our science blog even if there was no observation.
Restoring Instruments
After completing the standard operating procedure, we would have breakfast and go to bed at dawn, closing the shield of the observatory, putting the covers back on the optical telescopes, and turning off the machine. We called it a "day."
關注天氣
大氣層中的水氣會嚴重吸收微波訊號，因此觀測必須在晴朗且低濕度（原則上須低於 40%）的環境中進行。 如果天氣條件不佳，例如多雲、降雨，甚至下雪，我們就不會打開觀測站的遮罩進行觀測。
準備觀測工作
為了避免日落前後的氣溫差異造成儀器形變，我們會在午後就打開觀測站的遮罩， 並將載有探測器的平台升起至待命位置，讓儀器能夠藉由充分的空氣對流與環境達到熱平衡。 接著我們會確認每一個探測器的運作溫度及暗電流干涉狀態，並且停止接收來自異常探測器的訊號。
測量宇宙為波背景
正式觀測時，我們會根據觀測計劃將指令送達阿米巴的控制系統。 每一組資料都是由兩次歷時相同的曝光所組成，其中一次直接測量來自星系團方向的訊號， 另一次則是測量鄰近該星系團的空白天區。
蒐集校正資校
校正資料和宇宙微波背景同樣重要，因為它可以用來校正訊號的強度與相位。 我們通常會用太陽系中的行星當作校正的基準，主要是因為它們夠亮， 而且人們也能夠即時掌握每一顆行星的物理特性。
撰寫操作日誌
將觀測的情形與操作步驟記錄下來，對於事後分析資料有很大幫助，特別是排除疑難雜症的時候， 因此我們會在每天觀測結束時撰寫操作日誌，記錄天氣條件、儀器狀態，以及實際運作的行程，並發布在專用部落格上。 為了能夠迅速釐清當天的儀器狀態，我們也會將基線暗電流干涉圖放在日誌中。
復原儀器
將儀器回歸原位，關閉觀測站遮罩，蓋上光學望遠鏡的主鏡蓋，並且將控制系統關機，一天的工作就完成了！ 下崗後，我們會去吃早餐，享受寧靜的清晨時光，然後洗漱就寢。
My co-workers
My advisor, Professor Jiun-Huei Proty Wu, led the AMiBA data-analyzing team in NTU and thus sent students to the AMiBA site as on-site scientists, working with local operators.
Team
我的工作夥伴
吳俊輝老師是我的學位論文指導教授，他領導台大物理系團隊進行阿米巴資料分析，
並安排團隊成員到觀測現場與當地科學家和操作員學習。
Team
Jia-Long Johnny Yeh
Johnny travelled with me to the AMiBA site from April to May 2014, when he was a doctoral student advised by Professor Jiun-Huei Proty Wu. His expertise was in cosmic strings, in particular, the induced CMB B-mode polarization. Johnny is good at programming. His superb programming skills enabled him to perform numerical simulations of cosmic strings on a large scale with high resolution and dynamic range. He earned his Ph.D. and started to work at WorldQuant Research LLC Taiwan Branch as a quantitative finance researcher in 2017.
Johnny worked with Solomon Ho at the AMiBA site. On the other hand, he developed a simple program for operators to write the daily report. This program provided an efficient way to record information and dramatically reduced human error.
葉佳隆（Johnny）
2014 年 4 月至 5 月時，同樣接受吳俊輝老師指導的博士生佳隆和我一起前往阿米巴進行觀測， 並且搭配當地操作員 Solomon Ho 上山值勤。 除了例行觀測工作外，佳隆還利用空閒時間開發出「觀測日誌產生器」， 讓操作員得以用簡單且直覺的方式快速產生觀測日誌，避免原本因人工撰寫而可能產生錯誤的情況發生， 並且大幅提高現場操作及事後分析的效率。
佳隆主要的博士研究，則是計算宇宙弦如何在宇宙微波背景 B-mode 偏振光留下印記， 並且透過出色的程式撰寫能力，以超高解析度和超高動態範圍數值模擬，探討大尺度結構上的宇宙弦演化。 2017 年獲得博士學位後，他以計量金融研究員的身分，成為美商世坤台灣分公司的一份子。
Shang-Ping Pai
Shang-Ping was the partner on my first AMiBA journey from June to July 2013 when he was a master student advised by Professor Jiun-Huei Proty Wu. By using the data of the Sunyaev–Zel'dovich (SZ) effect from AMiBA and gravitational lensing from the Hubble Space Telescope, he produced a projected two-dimensional map of baryonic fraction for galaxy clusters, allowing scientists to test dark matter models. After receiving the master's degree in 2017, he became a doctoral student in Professor Wu's group.
Shang-Ping worked with Emmanuel Nunez at the AMiBA site during his visit in 2013.
白尚平（Peter）
尚平是吳俊輝老師指導的碩士班學生，和我一起在 2013 年 6 月至 7 月間前往阿米巴現場進行觀測， 並與當地操作員 Emmanuel Nunez 一同在山上值勤。 他的研究課題是利用阿米巴陣列所觀測到的資料，分析星系團造成的 Sunyaev–Zel'dovich（SZ）效應， 並將他們與哈伯太空望遠鏡所觀測到的重力透鏡資料進行比較，以計算星系團的質量分布。 在碩士論文中，他成功計算出星系團重子質量的二維投影分布圖，並以此來驗證諸多「暗物質」模型。
在 2017 年獲得碩士學位後，尚平繼續留在吳老師團隊中進行博士研究。
Fu-Cheng Wang
Fu-Cheng was a core member of the AMiBA team since he was a doctoral student in 2004. He focused his doctoral research on the power spectrum and SZ effect of CMB. After combining SZ data from AMiBA and several other experiments to deliver the multi-frequency analysis, he yielded a better estimation for the distributions of dark matter in a couple of galaxy clusters. Fu-Cheng kept working with AMiBA as a postdoctoral fellow in Professor Wu's group since 2011.
Fu-Cheng was the first observational partner of mine. He directed me to operate instruments when we stayed at the AMiBA site for three nights."
王富正（Ven）
自從 2004 年開啟博士生涯，Ven 就是阿米巴團隊的核心成員，並且專注於研究宇宙微波背景輻射的功率頻譜以及 SZ 效應。 結合阿米巴的數據以及其他實驗的觀測結果，並且進行多波段分析之後，Ven 更好地估計諸多星系團的「暗物質」分布。 在吳俊輝老師的指導下取得博士學位後，Ven 在 2011 年開始在吳老師團隊中擔任博士後研究員， 持續參與阿米巴計畫，並且協助指導後續加入的學弟妹。
Ven 是我前往阿米巴現場的第一位值勤搭檔，並且花了三個晚上指導我如何操作阿米巴進行觀測。
Chih-Wei Locutus Huang
Locutus was also a core member of the AMiBA team since he was a doctoral student in 2004. He solved several key issues during the operation of AMiBA in the early stage and studied the properties of galaxy clusters using AMiBA data. After completing his doctoral research, he moved to ASIAA as a postdoctoral fellow in 2009. He then became a support scientist of Greenland Telescope (GLT) and Very Long Baseline Array (VLBA) since 2012.
Locutus worked with Fu-Cheng at the AMiBA site before Shang-Ping and my visit. We completed the observation for the first time together.
黃智威（Locutus）
Locutus 也是阿米巴團隊的核心成員，自 2004 年進入博士班接受吳俊輝老師指導以來，就開始參與當時還在建置階段的阿米巴計劃。 他解決了計劃早期所面臨的許多關鍵議題，並且利用阿米巴的觀測資料解讀星系團的物理性質。 獲得博士學位以後，Locutus 在 2009 年前往中研院天文所擔任博士後研究員， 並且在 2012 成為格陵蘭望遠鏡（GLT，Greenland Telescope）以及超長基線陣列（VLBA，Very Long Baseline Array）的支援科學家。
在我和尚平初次前往阿米巴之前，Locutus 和 Ven 兩人搭檔在當地值勤，我們四人也一起上山完成了第一天觀測。
Anthony Ridenour
Anthony was a local operator of AMiBA and worked with me at the AMiBA site in June and July, 2013.
Anthony Ridenour
Anthony 是當地的天文台操作員，也是我在 2013 年 6 月至 7 月造訪阿米巴時的值勤搭檔。
Chia-You Shih
Chia-You was a local operator of AMiBA and worked with me at the AMiBA site from April to November, 2014. He was also an amateur astronomy enthusiast and astrophotographer. We observed together the lunar eclipse taking place on April 15 and October 8, 2014.
施佳佑（CY）
CY 是常駐當地的天文台操作員，並且在我 2014 年 4 月至 11 月造訪阿米巴時，與我搭檔上山值勤。 他也是一位天文攝影愛好者，經常在值勤的空檔架起望遠鏡開始拍攝，我們一起在山上記錄了 2014 年 4 月 15 日以及 10 月 8 日兩次月食。
More AMiBA photos
AMiBA and MLO have one of the top-three starry heaven in the world, breath-taking sea of clouds, and volcanic terrain spreading out far beyond the horizon.
Gallery
更多阿米巴照片
阿米巴所在的毛納羅亞觀測站是世界上頂級的星空天堂，擁有令人屏息的雲海和一望無際的火山地形，甚至可以眺望數十公里外的毛納基亞山和綿延的大島海岸線，景緻十分壯觀。
Gallery
