共查询到20条相似文献，搜索用时 62 毫秒
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利用星团谱样本的星族合成方法,分析了四个蓝致密星系（ＢｌｕｅＣｏｍｐａｃｔＧａｌａｘｉｅｓ,ＢＣＧ）的光学谱．给出了在各个ＢＣＧ中,年龄和金属丰度不同的星族对星系５８７ｎｍ处连续谱流量贡献的比率,同时还给出ＢＣＧ内部恒星演化的历史和星系内部的红化值．通过对星系内部星族及光谱的分析,解决了ＢＣＧ研究中存在的这类星系年龄和其内部光学不可见物质等问题．结果表明ＢＣＧ是年老星系,其内部恒星形成过程为长时间的宁静相上叠加有短暂且剧烈恒星形成的爆发,其内部存在光学不可见物质,且至少有一部分为年老的球状星团;根据由光学连续谱和发射线计算星系的内红化值的不同,得出ＢＣＧ星系内部尘埃对连续谱和发射线的产生区遮挡程度不同． 相似文献
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蓝致密星系谱的星族合成 总被引：1，自引：0，他引：1
利用星团谱样本的星族合成方法,分析了四个蓝致密星系（ＢｌｕｅＣｏｍｐａｃｔＧａｌａｘｉｅｓ,ＢＣＧ）的光学谱,给出了在各个ＢＣＧ中,年龄和金属丰度不同的星族对星系５８７ｎｍ处连续谱测量贡献的比率,同时还给出了ＢＣＧ内部恒星演化的历史和星系内部的红化值,通过对星系内部星族及光蝗分析,解决了ＢＣＧ研究中存在的这类星系年龄和其内部光学不可见物质等问题,结果表明ＢＣＧ是年老星系,其内部恒星形成过程为长时间 相似文献
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对兴隆６０ｃｍ望远镜主焦ＣＣＤ系统的测光性能进行了测试和研究．测定了ＣＣＤ快门时间函数,讨论了快门延迟效应对短时间曝光观测的可能影响．通过观测大批Ｌａｎｄｏｌｔ标准星,较准确地定出了ＢＶＲＩ宽带测光的星等系统转换关系,结果表明本系统与标准ＢＶＲＩ系统很接近．对ＣＣＤ系统的天文测光精度作了仔细的检验和分析,并对ＰＳＦ拟合测光和孔径测光两种方法进行了比较 相似文献
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利用星团谱样本的星族合成方法,分析了７个ＢＣＤＧ的光学谱,研究蓝致密矮星系（ＢＣＤＧ）内部的恒星形成历史、能源机制和尘埃分布情况．星族合成结果不仅能够解释ＢＣＤＧ的主要观测特征,解决ＢＣＤＧ研究中存在的一些问题,而且揭示了ＢＣＤＧ的一些未知的特性．谱合成结果表明：ＢＣＤＧ是年老的天体,其内部较早已经有恒星形成发生,恒星形成呈爆发式的,在ｔ＝５×１０７～１０９ｙｒ时的恒星形成率较高,最近（ｔ＝１０７ｙｒ）的恒星形成率开始下降;光谱分析显示大量大质量的年轻恒星提供了ＢＣＤＧ中心区的主要能源．利用扣除恒星吸收影响的发射线光谱,计算了发射线产生区的内红化值,发现它明显大于由连续谱计算得到的内红化值,这种差异的可能解释是ＢＣＤＧ内部尘埃对连续谱和发射线的产生区遮挡程度不同．最后,比较了ＢＣＧ和ＢＣＤＧ星族合成结果,提出了矮星系间一种可能的演化序列． 相似文献
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对兴隆６０ｃｍ望远镜主焦ＣＣＤ系统的测光性能进行了测试和研究,测定了ＣＣＤ快门时间函数,讨论了快门延迟效应对短时间曝光观测的可能影响,通过观测大批Ｌａｎｄｏｌｔ标准星,较准确地定出了ＢＶＲＩ宽带测光的星等系统转换关系,结果表明本系统与标准ＢＶＲＩ系统很接近,对ＣＣＤ系统的天文测光精度作了仔细的检验和分析,工对ＰＳＦ拟合测光和孔径测光两种方法进行了比较。 相似文献
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利用已知的统计结果对高红移类星体光谱进行Ｍｏｎｔｅ Ｃａｒｌｏ模拟，得到了ＵＢＶＲＩ五色测光的色指数，并利用模拟的选择判据计算了选择效应函数，当２．４＜ｚ＜３．０时，选择效应来自于与主序星的混淆，当ｚ＞３．０时，则是由于较暗的类星体与晚矮星同时从Ｕ．Ｂ等颜色的图像上消失，导致可利用色指数的减少。 相似文献
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利用已知的统计结果对高红移类星体光谱进行ＭｏｎｔｅＣａｒｌｏ模拟，得到了ＵＢＶＲＩ五色测光的色指数，并利用模拟的选择判据计算了选择效应函数，当２．４＜ｚ＜３．０时，选择效应来自于与主序星的混淆；当ｚ＞３．０时，则是由于较暗的类星体与晚型矮星同时从Ｕ．Ｂ等颜色的图象上消失，导致可利用色指数的减少。 相似文献
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星族合成方法及发射线星系核区中的恒星组分 总被引：1，自引：0，他引：1
论述星族合成方法对研究复合恒星体系的重要意义。综述了星族合成的三种基本方法，着重介绍了以星团光谱为样本的星族合成方法及其应用，最后，作为一个例子，我们利用ＣＳＰＳ方法给出发射线星系Ｍｒｋ４９９谱的合成结果。 相似文献
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给出了１９９７年４月１５日至１７日在北京天台用２．１６ｍ望远镜卡焦光谱仪观测获得的６颗激变变星（ＡＢ Ｂｏｏ,ＵＸ ＵＭａ,Ｔ ＣｒＢ,ＡＨ Ｈｅｒ,Ｚ Ｃａｍ和Ｖ４２６ Ｏｐｈ）及３颗相关天体（ＵＭａ３,ＥＧ ＵＭａ和Ｌｅｏ３）的ＣＣＤ光谱,并同时拍摄了５颗晚型星（３Ｄｒａ,ｖ Ｖｉｒ,ψＬｅｏ,３４Ｂｏｏ和３６Ｃｏｍ）的ＣＣＤ光谱,作为晚型星参考谱,测量了观测样本星的Ｈα和近红外ＣａⅡ的三重 相似文献
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Solar System Research - Finding and studying possible collisions of asteroids approaching the Earth requires a significant amount of computation. This paper describes the R0 program created to... 相似文献
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Many asteroids with a semimajor axis close to that of Mars have been discovered in the last several years. Potentially some of these could be in 1:1 resonance with Mars, much as are the classic Trojan asteroids with Jupiter, and its lesser-known horseshoe companions with Earth. In the 1990s, two Trojan companions of Mars, 5261 Eureka and 1998 VF31, were discovered, librating about the L5 Lagrange point, 60° behind Mars in its orbit. Although several other potential Mars Trojans have been identified, our orbital calculations show only one other known asteroid, 1999 UJ7, to be a Trojan, associated with the L4 Lagrange point, 60° ahead of Mars in its orbit. We further find that asteroid 36017 (1999 ND43) is a horseshoe librator, alternating with periods of Trojan motion. This asteroid makes repeated close approaches to Earth and has a chaotic orbit whose behavior can be confidently predicted for less than 3000 years. We identify two objects, 2001 HW15 and 2000 TG2, within the resonant region capable of undergoing what we designate “circulation transition”, in which objects can pass between circulation outside the orbit of Mars and circulation inside it, or vice versa. The eccentricity of the orbit of Mars appears to play an important role in circulation transition and in horseshoe motion. Based on the orbits and on spectroscopic data, the Trojan asteroids of Mars may be primordial bodies, while some co-orbital bodies may be in a temporary state of motion. 相似文献
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P. Maltby 《Solar physics》1972,26(1):76-82
Observations of the penumbral intensity of sunspots in 13 wavelength regions are presented. In 4 wavelength regions 54 sunspots are measured. In the other wavelength regions the number of sunspots considered ranges from 3–19.The penumbral intensity alters with position within the spot. This intensity variation is found to be comparable with the change in intensity from one spot to another. The penumbral intensity is found to be independent of spot size in the sample considered.The penumbra model of Kjeldseth Moe and Maltby (1969) with = 0.055 is supported by the measurements. 相似文献
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Magnetars are the neutron stars with the highest magnetic fields up to 1015–1016 G. It has been proposed that they are also responsible for a variety of extra-galactic phenomena, ranging from giant flares in nearby galaxies to fast radio bursts. Utilizing a relativistic mean field model and a variable magnetic field configuration, we investigate the effects of strong magnetic fields on the equation of state and anisotropy of pressure of magnetars. It is found that the mass and radius of low-mass magnetars are weakly enhanced under the action of the strong magnetic field, and the anisotropy of pressure can be ignored. Unlike other previous investigations, the magnetic field is unable to violate the mass limit of the neutron stars. 相似文献
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In the text-books of astronomy, sections generally related to the Moon deal with the orbital elements of the Earth-Moon system such asa, e, i, ,
and the time of perigee passage. While the MEAN of the first of the three elements do not vary, mean longitude of the ascending node-mean longitude of the lunar perigee and the time of perigee passage undergoes secular as well as periodic changes due predominantly to the action of the Sun's gravitational attraction. While to a certain degree, explanations related to the calculation of the lunar orbit parameters are given, not a single graphical representation of these short- or long-periodic changes are presented. We allow the number of data related to these periodic changes must cover a large span of time; and if regression of the line of nodes or advances of the line of apses are to be graphically seen, data covering 18.61 and 8.85 yr, respectively, are needed. In this work we particularly aim at the graphical representation of the periodic changes of the line of nodes. 相似文献
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