| Evolution of M81 with Exponentially Decreasing Star Formation Rate of PEGASE |
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| 作者姓名： | Jiu-Li Li Xu Zhou Jun Ma and Jian-Sheng Chen
National Astronomical Observatories Chinese Academy of Sciences Beijing |
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| 作者单位： | Jiu-Li Li，Xu Zhou，Jun Ma and Jian-Sheng Chen
National Astronomical Observatories，Chinese Academy of Sciences，Beijing 100012; |
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| 基金项目： | Supported by the National Natural Science Foundation of China |
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| 摘 要： | Based on the large field multicolor observations of Beijing-Arizona-Taiwan-Connecticut (BATC) program, we obtain the spectral energy distribution (SED) for individual regions of M81. We study the structure and evolution of M81 with an evolutionary population synthesis (EPS) model, PEGASE. We find that the exponentially deceasing star formation rate (SFR) with star formation scale 3 Gyr (hereafter Exp, τ=3 Gyr) gives the best agreement between the model predictions and the observed SEDs. We then obtain the structure, age distribution and evolutionary history of M81. There is a clear age gradient between the central and outer regions. The populations in the central regions are older than 7 Gyr,those in the outer regions are younger, at about 4.5 Gyr. The youngest components in the spiral arms have ages of about 2.5 Gyr or less.
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| 关 键 词： | 旋涡星云 角大小 天文观测 恒星 |
Evolution of M81 with Exponentially Decreasing Star Formation Rate of PEGASE |
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| Jiu-Li Li,Xu Zhou,Jun Ma and Jian-Sheng Chen
National Astronomical Observatories,Chinese Academy of Sciences,Beijing ,.Evolution of M81 with Exponentially Decreasing Star Formation Rate of PEGASE[J].Chinese Journal of Astronomy and Astrophysics,2004,4(2):143-152. |
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| Authors: | Jiu-LiLi XuZhou JunMa Jian-ShengChen |
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| Institution: | NationalAstronomicalObservatories,ChineseAcademyofSciences,Beijing100012 |
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| Abstract: | |
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| Keywords: | galaxies: individual (M81) - galaxies: evolution - galaxies: star general |
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