标题： M31中172个球状星团的光谱能量分布和年龄估计 显示英文标题

标题： Spectral Energy Distributions and Age Estimates of 172 Globular Clusters in M31

摘要： 本文给出了来自博洛尼亚星表（Battistini 等人，1987年）的近邻漩涡星系M31中的172个球状星团（GCs）的CCD多色测光观测。这些观测使用国家天文台60/90厘米施密特望远镜，在13个中间波段滤光片下进行，覆盖了从3800到10000埃的波长范围。这为我们提供了M31的多色像素图，分辨率为1.7"*1.7"。通过孔径测光，我们获得了这些球状星团的光谱能量分布（SEDs）。利用观测所用的BATC中间波段系统与UBVRI宽带系统的对应关系，我们得到了B和V波段的星等。计算得到的V波段和B-V波段与Battistini等人（1987年）以及Barmby等人（2000年）给出的值一致。最后，通过对每个球状星团的测光数据与理论恒星群体综合模型进行比较，我们估计了不同金属丰度样本球状星团的年龄。结果显示，几乎所有我们的样本球状星团的年龄都超过10^{9}年，大多数约为10^{10}年。此外，我们发现由贫金属模型拟合的球状星团通常比由富金属模型拟合的球状星团更古老。 显示英文摘要

摘要： In this paper we present CCD multicolor photometry for 172 globular clusters (GCs), taken from the Bologna catalog (Battistini et al. 1987), in the nearby spiral galaxy M31. The observations were carried out by using the National Astronomical Observatories 60/90 cm Schmidt Telescope in 13 intermediate-band filters, which covered a range of wavelength from 3800 to 10000A. This provides a multicolor map of M31 in pixels of 1.7"*1.7". By aperture photometry, we obtain the spectral energy distributions (SEDs) for these GCs. Using the relationship between the BATC intermediate-band system used for the observations and the UBVRI broad-band system, the magnitudes in the B and V bands are derived. The computed V and B-V are in agreement with the values given by Battistini et al. (1987) and Barmby et al. (2000). Finally, by comparing the photometry of each GC with theoretical stellar population synthesis models, we estimate ages of the sample GCs for different metallicities. The results show that nearly all our sample GCs have ages more than 10^{9} years, and most of them are around 10^{10} years old. Also, we find that GCs fitted by the metal-poor model are generally older than ones fitted by the metal-rich model.