以最佳化影像相減法尋找類星體

Abstract

摘要 本文將介紹利用最佳化影像相減 (OIS) 法搜尋可能受到星系團的重 力透鏡作用的類星體。利用互動式數據語言 (IDL) 軟體編譯 OIS 運算 程式來找出同一望遠鏡、同一濾鏡、同一天空但不同觀測時間及條件 的兩張影像之間觀測條件的差異，並使其趨於一致。將兩張影像相減， 並檢查剩下的影像，可以此觀測星體的光度變化，進而篩選出具有亮 度變化的星體。即為可能的類星體。本文將觀測普朗克 (PLANCK) 太 空望遠鏡利用蘇尼亞耶夫 -澤爾多維奇效應 (SZeffect) 找出的星系團附 近的天空，並重複利用 OIS 運算法於泛星 (Pan-STARRS) 望遠鏡所觀 測的不同時間及觀測條件的影像，搜尋具有光度變化的類星體。

Abstract In this thesis, we use the Optimal Image Subtraction (OIS) method to search for the candidates of quasi-stellar objects (quasars) lensed by galaxy clusters. We use the OIS algorithm in Interactive Data Language(IDL) code to figure out the optimal point spread functions between two images from the same telescope, same filter and same position but differ in time and the seeing conditions to make their seeing almost the same. By subtracting the two images and examining the residual images, we can identify objects vary in brightness or position. We select the objects nearby the PLANCK cluster candidates detected by the Sunyaev–Zel’dovich effect (SZ effect), and use theOISmethodontherepeatedlyobservedPan-STARRSimagestolookfor quasars vary in brightness. With the new OIS method, we also improve the OISmethodoriginallyadoptedbyPan-STARRScollaboration.