标题： 均相光度学 V：球状星团 NGC 4147 显示英文标题

标题： Homogeneous Photometry V: The Globular Cluster NGC 4147

摘要： 为球状星团NGC 4147提供了新的BVRI宽带测光和天体测量数据，这些数据基于从524幅地面CCD图像的测量值，这些图像大多由同事捐赠或从公共档案中检索而来。 我们还重新分析了用哈勃太空望远镜上的WFPC2获得的该星团的五次曝光，使用的是F439W和F555W（B和V）滤光片。 我们展示了校准后的色-星等图和色-色图。 色-星等图的分析显示形态特性与已发表的该星团金属丰度估计总体一致，并且年龄与其他具有相似金属丰度的银河系球状星团典型年龄相符。 我们还重新确定了RR Lyrae变星的周期和平均星等，其中包括这里首次报道的新c型变星。 我们的数据显示候选体V18没有明显的光变证据，这是Arellano Ferro等人（2004年）最近报告的结果。 这些观测也支持候选体V5、V9和V15是非变星的状态。 我们将我们的光变曲线数据与Newburn（1957年）、Mannino（1957年）以及Arellano Ferro等人（同上引用）的数据结合，可以显著改善周期的推导。 平均周期和Bailey周期-振幅图支持将该星团归类为Oosterhoff I型，尽管它的水平分支主要偏蓝。 另一方面，c型到ab型RR Lyrae变星的数量比对于一个Oosterhoff I型星团来说异常高。 校准后的结果已经通过第一作者的网站发布。 显示英文摘要

摘要： New BVRI broad-band photometry and astrometry are presented for the globular cluster NGC 4147, based upon measurements derived from 524 ground-based CCD images mostly either donated by colleagues or retrieved from public archives. We have also reanalysed five exposures of the cluster obtained with WFPC2 on the Hubble Space Telescope in the F439W and F555W (B and V) filters. We present calibrated color-magnitude and color-color diagrams. Analysis of the color-magnitude diagram reveals morphogical properties generally consistent with published metal-abundance estimates for the cluster, and an age typical of other Galactic globular clusters of similar metallicity. We have also redetermined the periods and mean magnitudes for the RR Lyrae variables, including a new c-type variable reported here for the first time. Our data do not show clear evidence for photometric variability in candidate V18, recently reported by Arellano Ferro et al. (2004). These observations also support the non-variable status of candidates V5, V9, and V15. The union of our light-curve data with those of Newburn (1957), Mannino (1957) and Arellano Ferro et al. (op. cit.) permits the derivation of significantly improved periods. The mean periods and the Bailey period-amplitude diagrams support the classification of the cluster as Oosterhoff I despite its predominantly blue horizontal branch. The number ratio of c- to ab-type RR Lyrae stars, on the other hand, is unusually high for an Oosterhoff I cluster. The calibrated results have been made available through the first author's web site.