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arXiv 0704.1576astro-ph
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M33中的候选星团星表

A Catalog of Star Cluster Candidates in M33

Ata Sarajedini, Conor L. Mancone

摘要:

我们提出了一个新的星团候选人在附近的螺旋星系M33的目录。它是基于八个现有的目录,其中我们有交叉引用的标识和endemonies,以解决它们之间的不一致。我们的目录包含451个候选者,其中255个是基于HST和高分辨率地基成像确认的星团。该星表包含精确的星系团位置(RA和Dec),UBVRIJHKs过滤器中的星等和颜色,金属丰度,径向速度,质量和年龄,以及每个星系团的银河中心距离。M33星系团的颜色分布与大麦云星系团的颜色分布相似,主峰在(B-V)o~0.15和(B-V)o~0.65。内禀色与星团年龄相关,年龄范围从10^{7.5}年到10^{10.3}年。星团的年龄分布支持星团快速分裂的概念,在dN_{cluster} /dt ~ t^{alpha}关系中,α的斜率为-1.09 +/- 0.07。此外,与理论上的单个恒星星族模型的比较表明,这些星系团之间存在年龄-金属丰度关系,年轻的星系团更富含金属。对星系团径向分布的分析表明,年轻的星系团(年龄<1 Gyr)可能比老的星系团更集中在M33的中心。与M33场星的径向轮廓类似的比较显示,在大于99.9%的置信水平下,星团更加集中。可能的原因,这是提出和讨论,然而,压倒性的结论似乎是,一个更完整和彻底的集群搜索,需要覆盖至少4平方度的M33为中心。

英文摘要:

We present a new catalog of star cluster candidates in the nearby spiral galaxy M33. It is based on eight existing catalogs wherein we have cross-referenced identifications and endeavored to resolve inconsistencies between them. Our catalog contains 451 candidates of which 255 are confirmed clusters based on HST and high resolution ground-based imaging. The catalog contains precise cluster positions (RA and Dec), magnitudes and colors in the UBVRIJHKs filters, metallicities, radial velocities, masses and ages, where available, and galactocentric distances for each cluster. The color distribution of the M33 clusters appears to be similar to those in the Large Magellanic Cloud with major peaks at (B-V)o~0.15, and (B-V)o~0.65. The intrinsic colors are correlated with cluster ages, which range from 10^{7.5} to 10^{10.3} years. The age distribution of the star clusters supports the notion of rapid cluster disruption with a slope of alpha=-1.09 +/- 0.07 in the dN_{cluster}/dt ~ t^{alpha} relation. In addition, comparison to theoretical single stellar population models suggests the presence of an age-metallicity relation among these clusters with younger clusters being more metal-rich. Analysis of the radial distribution of the clusters yields some evidence that younger clusters (age <~ 1 Gyr) may be more concentrated toward the center of M33 than older ones. A similar comparison with the radial profile of the M33 field stars shows the clusters to be more centrally concentrated at the greater than 99.9% confidence level. Possible reasons for this are presented and discussed; however, the overwhelming conclusion seems to be that a more complete and thorough cluster search is needed covering at least 4 square degrees centered on M33.

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