低核密度球狀星團NGC6144以及E3的X光與可見光波段之研究

• Main Authors: Lan, Shih-Hao, 藍仕豪
• Other Authors: Kong, Albert K.H.
• Format: Others
• Language: en_US
• Online Access: http://ndltd.ncl.edu.tw/handle/21319484586854449109

碩士 === 國立清華大學 === 天文研究所 === 97 === We report on the Chandra X-ray Observatory and Hubble Space Telescope observation of two low core density globular clusters, NGC6144 and E3. Within the half-mass radius and at a detection limit of L_X = 1.7 × 10^30 ergs/s , we found 6 X-ray sources in NGC6144, of which 4-5 are expected to be background sources; and 3 X-ray sources within the half-mass radius of E3, of which 2 are expected to be background sources. Therefore, we cannot exclude that all our sources are background sources. However, combining the results from X-ray and optical observations, we found that 1-2 sources in NGC6144 and 1 source in E3 are likely to be cataclysmic variables and that 1 source in NGC6144 is an active binary, based on the X-ray and optical properties. The number of faint X-ray sources in NGC6144 and E3 found with Chandra and HST is higher than a prediction based on collision frequency, but is closer to that based on mass. Our observations strongly suggest that the compact binary systems in NGC6144 and E3 are primordial in origin.