LOT Time-Series Observations of M31 Cepheids in BVRI Filters

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/83203

Title:	LOT Time-Series Observations of M31 Cepheids in BVRI Filters
Authors:	黃子豪;Huang, Tzu-Hao
Contributors:	天文研究所
Keywords:	造父變星;仙女座星系;距離尺度;Cepheids;M31;Distance scale
Date:	2020-08-17
Issue Date:	2020-09-02 15:08:05 (UTC+8)
Publisher:	國立中央大學
Abstract:	古典造父變星是用於測量到附近星系距離的標準燭光，我們計畫的目標是利用鹿林一米望遠鏡在BVRI波段的觀測的測量仙女座星系的距離。我們應用影像對減套件可以生成仙女座星系中已知長週期造父變星的光通量差曲線。通量的轉換是通過使用標準星和PSF光度法獲得。造父變星的平均星等是通過使用擬合光曲線的模板方法得出，平均星等的誤差是介於±0.05 到±0.1 星等之間。我們採用了不同的消光係數和週光關係的斜率來測量仙女座星系的距離模數。藉由使用Ngeow (2012) 中給出的週光關係斜率，我們得到的距離模數是μ0 = 24.299 ± 0.042 和24.300 ± 0.042；如果我們採用Ngeow和Kanbur (2004) 的週光關係斜率，則距離模數是μ0 = 24.445 ± 0.049 和24.446 ± 0.04，其中兩個值分別對應到兩個不同的消光係數RV = 2.7 和3.1。;Classical Cepheid variable stars are standard candles for measuring distance to nearby galaxies. The goal of our project is to measure the distance of M31 by using the Lulin One-meter Telescope observed in BVRI-band. We applied an images subtraction package to create differential flux light curves for the known long period Cepheids in M31. Flux to magnitude conversion is obtained by using standard stars together with PSF photometry. The Cepheid mean magnitudes were derived from using a template light curve fitting approach, with typical errors on mean magnitudes is ±0.05 to ±0.1. We adopted different extinction values and slopes of the period-luminosity (P-L) relations to measure the distance modulus to M31. Our results with RV = 2.7 and 3.1 are μ0 = 24.299 ± 0.042 and 24.300 ± 0.042 from using the P-L slopes given in Ngeow (2012). If we adopted the P-L slopes from Ngeow and Kanbur (2004), then μ0 = 24.445 ± 0.049 and 24.446 ± 0.04 with the two values of RV , respectively.
Appears in Collections:	[Graduate Institute of Astronomy] Electronic Thesis & Dissertation

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