论文标题
NGC 1291的古代球状簇
The Ancient Globular Clusters of NGC 1291
论文作者
论文摘要
我们提供了一个新的目录，其中包括早期型螺旋（SB0/A）Galaxy NGC 1291中的81个古代球状簇（GC）。从B，V和I带图像中选择了Hubble Space望远镜的候选者，该候选者也显示了17个年轻（T <几个X <x 100myr）群集。光度函数显示出类似于其他螺旋和椭圆星系中GC系统的峰值形状。古老的簇具有双峰颜色分布，大约65％（35％）的蓝色（红色）颜色。红色，大概是金属丰富的GC的集中浓缩，如凸起的人群所预期的。虽然蓝色，大概是金属贫困的GC，但分布更广泛，与对光环种群的期望一致。 NGC 1291中GC的特异性频率高于大多数螺旋星系中以前发现的特异性频率。但是，如果我们仅考虑蓝色亚群，我们会发现SN，蓝色= 0.50 +/- 0.06，与其他螺旋的相似。该结果支持螺旋中普遍存在的晕圈GC人群的假设。与其他星系中的红色GC相比，NGC 1291中的红色GC的比例表明，它们与宿主星系类型相关，而不是与宿主星系光度相关。
We present a new catalog of 81 ancient globular clusters (GCs) in the early-type spiral (SB0/a) galaxy NGC 1291. Candidates have been selected from B,V, and I band images taken with the Hubble Space Telescope, which also reveal 17 younger (t < few x 100Myr) clusters. The luminosity function shows a peaked shape similar to that found for GC systems in other spiral and elliptical galaxies. The ancient clusters have a bimodal color distribution, with approximately 65% (35%) of the population having blue (red) colors. The red, presumably metal-rich GCs are more centrally concentrated, as expected for a bulge population; while the blue, presumably metal-poor GCs, are more broadly distributed, consistent with expectations of a halo population. The specific frequency of GCs in NGC 1291 is higher than found previously in most spiral galaxies. However, if we consider just the blue subpopulation, we find Sn,blue=0.50 +/- 0.06, quite similar to that found for other spirals. This result supports the hypothesis of a universal population of halo GCs in spirals. The fraction of red GCs in NGC 1291, when compared with those found in other galaxies, suggests that these correlate with host galaxy type rather than with host galaxy luminosity.
