论文标题
与光谱法和光度法的恒星簇样品的物理参数的不同拟合方法的比较
Comparisons of Different Fitting Methods for the Physical Parameters of A Star Cluster Sample of M33 with Spectroscopy and Photometry
论文作者
论文摘要
恒星簇是星系形成和演变的良好示踪剂。我们通过使用光谱（或结合光度法）来比较不同的拟合方法来确定物理参数。我们选择了M33中17个星团的样本，该样品以前缺乏光谱观测。低分辨率光谱是用NaOC的2.16-m反射剂进行的。拟合中使用的光度法包括$ \ rm u_ {sc} $和$ \ rm v_ {sage} $ bands the Sage Survey中的bands，以及已发表的$ ubvri $和$ ugriz $ photometry。我们首先使用{\ sc ulyss}（Vazdekis等人和{\ sc pegase-hr}）SSP模型和Bruzual \＆Charlot（2003）（BC03）Stellar人群合成模型的全谱拟合模型。 BC03和{\ sc ulyss}模型的拟合结果似乎也与以前的作品一致。然后，我们添加Sage $ \ rm U_ {SC} $和$ \ rm V_ {Sage} $光度法，使用BC03型号的光谱拟合中。似乎结果变得好多了，尤其是对于Padova 2000+Chabrier IMF集。最后，我们添加了更多的光度计数据，即$ ubvri $和$ ugriz $，在拟合中，我们发现结果并没有显着改善。因此，我们得出的结论是，光度法对于改善拟合结果很有用，尤其是对于蓝带（$λ<4000 $Å），例如，$ \ rm u_ {sc} $和$ \ rm v_ {sage} $ band。最后，我们讨论了星团簇的“ UV-Excess”，我们发现五个星形簇具有基于$ galex $ fuv的NUV光度法的UV-Excess。
Star clusters are good tracers for formation and evolution of galaxies. We compared different fitting methods by using spectra (or by combining photometry) to determine the physical parameters. We choose a sample of 17 star clusters in M33, which previously lacked spectroscopic observations. The low-resolution spectra were taken with the Xinglong 2.16-m reflector of NAOC. The photometry used in the fitting includes $\rm u_{SC}$ and $\rm v_{SAGE}$ bands from the SAGE survey, as well as the published $UBVRI$ and $ugriz$ photometry. We firstly derived ages and metallicities with the {\sc ULySS} (Vazdekis et al. and {\sc pegase-hr}) SSP model and the Bruzual \& Charlot (2003) (BC03) stellar population synthesis models for the full-spectrum fitting. The fitting results of both the BC03 and {\sc ULySS} models seem consistent with those of previous works as well. Then we add the SAGE $\rm u_{SC}$ and $\rm v_{SAGE}$ photometry in the spectroscopic fitting with the BC03 models. It seems the results become much better, especially for the Padova 2000+Chabrier IMF set. Finally we add more photometry data, $UBVRI$ and $ugriz$, in the fitting and we found that the results do not improve significantly. Therefore, we conclude that the photometry is useful for improving the fitting results, especially for the blue bands ($λ<4000$ Å), e.g., $\rm u_{SC}$ and $\rm v_{SAGE}$ band. At last, we discuss the "UV-excess" for the star clusters and we find five star clusters have UV-excess, based on the $GALEX$ FUV, NUV photometry.
