论文标题
明亮椭圆星系NGC 3613及其球状群集系统的双子座/GMOS研究
A Gemini/GMOS study of the bright elliptical galaxy NGC 3613 and its globular cluster system
论文作者
论文摘要
我们介绍了E Galaxy NGC 3613（MV = -21.5，D = 30.1 MPC）的球状簇系统（GCS）的首次光度研究，以及基于Gemini/GMOS图像的宿主星系的表面光度法。 NGC 3613被认为是一个组的中央星系，尽管其固有的亮度与集群中心的星系的预期亮度相似，但居住在低密度的环境中。该GC获得以下特征。颜色分布是双峰的，金属贫穷的球状簇（GC）随着半径增加而变得略带蓝色。径向和方位角预测的分布表明，富含金属的GC更集中于宿主星系，并非常精确地追踪其光线分布，而金属贫困的GC则具有更扩展和更均匀的分布。 GC光度函数有助于验证所采用的距离。 NTOT的估计总GC总数= 2075 +/- 130导致特定频率SN = 5.2 +/- 0.7，这是具有相似光度的宿主星系的GCS的预期范围内的值。 NGC 3613的表面光度法揭示了一个三组分的轮廓和明显的子结构。最后，在宿主星系的周围环境中确定了一小部分超紧凑型矮人（UCD）候选物。
We present the first photometric study of the globular cluster system (GCS) of the E galaxy NGC 3613 (Mv = -21.5, d = 30.1 Mpc), as well as the surface photometry of the host galaxy, based on Gemini/GMOS images. Being considered the central galaxy of a group, NGC 3613 inhabits a low-density environment although its intrinsic brightness is similar to the expected one for galaxies in the centre of clusters. The following characteristics are obtained for this GCS. The colour distribution is bimodal, with metal-poor globular clusters (GCs) getting slightly bluer with increasing radius. The radial and azimuthal projected distributions show that metal-rich GCs are more concentrated towards the host galaxy and trace its light distribution very precisely, while metal-poor GCs present a more extended and uniform distribution. The GC luminosity function helps validate the adopted distance. The estimated total GC population of Ntot= 2075 +/- 130 leads to a specific frequency Sn=5.2 +/- 0.7, a value within the expected range for GCSs with host galaxies of similar luminosity. The surface photometry of NGC 3613 reveals a three-component profile and a noticeable substructure. Finally, a small sample of ultra-compact dwarf (UCD) candidates are identified in the surroundings of the host galaxy.
