论文标题
最近的Seyfert II星系Circinus的球状簇系统
The globular cluster system of the nearest Seyfert II galaxy Circinus
论文作者
论文摘要
语境。以前没有探测到Circinus Galaxy的球状簇（GC）系统，部分原因是星系的位置为-3.8 $^\ Circ $ Galactic Latitude，该纬度严重受到星际灭绝，恒星拥挤和银河污染的苦难。但是，通过ViaLáctea扩展调查（VVVX）中的Vista变量的深近红外（NIR）光度法结合GAIA EDR3的精确星形法，使我们能够在该区域绘制GCS。 目标。我们的长期目标是研究和表征Circinus Galaxy的GC和超紧凑型矮人的分布，这是最近的Seyfert II星系。在这里，我们在此星系中首次对GCS进行了试点搜索。 方法。我们将NIR VVVX光度法与GAIA EDR3星体特征（例如Astretric多余噪声和BP/RP多余系数）结合使用，以构建Circinus Galaxy中GC的第一个同质目录。选择标准的强大组合使我们能够从样本中有效清洁闯入者。 结果。我们报告了该银河系中$ \ sim $ 70 GC候选的检测，该候选人的置信度为3 $σ$。他们显示了双峰色分布，蓝色峰为（g-ks）$ _ 0 $ = 0.985 $ \ pm $ 0.127 mag，分散为0.211 $ \ pm $ 0.091 mag，红色峰和（g-ks）$ _ 0 $ _ 0 $ = 1.625 $ = 1.625 $ \ pm $ 0.177 mag，$ 0.177 mag，$ 0.177 mag $ 0.482 $ 0.482 $ \ pm \ 0.482 $ \ \ 0.482 $ \ \ 0.114.482 $ \ \ \ \ 0.482 $ \ \ \ \ \ \ 0.482 $ \ \ \ \ \ 0.482 $ \ \ \ 0.482 $ \。 GC特定的频率（S $ _n $）为1.3 $ \ pm $ 0.2，用于银河系，我们估计总人口为120美元$ \ pm $ 40 GCS。基于预计的径向分布，Circinus的GC候选分布与MW和M31的分布不同。 结论。我们证明Circinus Galaxy拥有大量的群集候选。这个结果是了解该银河系中旧恒星簇的演变的首次飞跃。
Context. The globular cluster (GC) system of Circinus galaxy has not been probed previously partly because of the location of the galaxy at - 3.8$^\circ$ Galactic latitude which suffers severely from interstellar extinction, stellar crowding, and Galactic foreground contamination. However, the deep near-infrared (NIR) photometry by the VISTA Variables in the Via Láctea Extended Survey (VVVX) in combination with the precise astrometry of Gaia EDR3 allow us to map GCs in this region. Aims. Our long-term goal is to study and characterise the distributions of GCs and Ultra-compact dwarfs of Circinus galaxy which is the nearest Seyfert II galaxy. Here we conduct the first pilot search for GCs in this galaxy. Methods. We use NIR VVVX photometry in combination with Gaia EDR3 astrometric features such as astrometric excess noise and BP/RP excess factor to build the first homogeneous catalogue of GCs in Circinus galaxy. A robust combination of selection criteria allows us to effectively clean interlopers from our sample. Results. We report the detection of$\sim$ 70 GC candidates in this galaxy at a 3 $σ$ confidence level. They show a bimodal colour distribution with the blue peak at (G-Ks)$_0$ = 0.985$\pm$0.127 mag with a dispersion of 0.211$\pm$0.091 mag and the red peak at (G-Ks)$_0$ = 1.625$\pm$0.177 mag with a dispersion of 0.482$\pm$0.114 mag. A GC specific frequency (S$_N$) of 1.3$\pm$0.2 was derived for the galaxy, and we estimated a total population of 120$\pm$40 GCs. Based on the projected radial distribution it appears that Circinus has a different distribution of GC candidates than MW and M31. Conclusions. We demonstrate that Circinus galaxy hosts a sizeable number of cluster candidates. This result is the first leap towards understanding the evolution of old stellar clusters in this galaxy.
