The globular cluster systems of NGC 3258 and NGC 3268 in the Antlia cluster
The globular cluster systems of NGC 3258 and NGC 3268 in the Antlia cluster
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Antlia 星团中的 NGC 3258 和 NGC 3268 球状星团系统
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
U. L. Plata
中科院分区：
文献类型：
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作者：
B. Dirsch;T. Richtler;L. I. U. D. Concepcion;U. L. Plata
安特利亚星系团是距离我们第三近的星系团，仅次于室女座和福纳克斯星系团。我们使用4米CTIO望远镜的广视场马赛克相机在最亮的星系团中搜索球状星系团，这些星系团在两个更大的椭圆体-NGC 3258和NGC 3268中被探测到。这些星系每个都有几千个星系团；NGC3258比NGC3268多。球状星团系统的颜色分布明显呈双峰分布。峰值颜色与其他椭圆形的颜色一致。球状星团系统的径向数密度分布对于这两个星系是不可区分的，也不能像在其他椭圆星系中观察到的那样，看到红色星团和蓝色星团在分布上的差异。NGC3268的光线轮廓似乎类似于Fornax星系团的中心星系NGC1399。NGC 3258具有较大半径时更陡峭的光线轮廓。这两个星系都表现出颜色的梯度，向外变得更蓝。在NGC3268中，内部300的颜色和形态表明存在内部尘埃盘。球状星系团系统在所研究的径向区域密切跟踪星系光。两个星系的星系团的伸长与两个星系的连接轴大致成大半径对齐。对于NGC3268和NGC3258，我们分别找到了S N=3：0.2：0和S N=6：0.2：5的径向频率范围内的特定频率。作为观测广域图像的副产品，我们描述了安特利亚螺旋星系NGC 3269的一种奇怪的吸收特征，我们认为它可能是投射到NGC 3269上的微小星系尘埃云。
The Antlia galaxy cluster is the third nearest galaxy cluster after Virgo and Fornax. We used the wide-field MOSAIC camera of the 4-m CTIO telescope to search in the brightest cluster galaxies for globular cluster systems, which were detected in the two larger ellipticals - NGC 3258 and NGC 3268. These galaxies each contain several thousand clusters; NGC 3258 more than NGC 3268. The color distributions of the globular cluster systems are clearly bimodal. The peak colors agree with those of other ellipticals. The radial number density profiles of the globular cluster systems are indistinguishable for the two galaxies and no dierence in the distribution of red and blue clusters - as observed in other elliptical galaxies - can be seen. The light profile of NGC 3268 appears to be similar to that of NGC 1399, the central galaxy of the Fornax cluster. NGC 3258 has a light profile which is steeper at large radii. Both galaxies exhibit color gradients, becoming bluer outwards. In NGC 3268, the color and morphology in the inner 3 00 indicate the presence of an inner dusty disk. The globular cluster systems closely trace the galaxy light in the studied radial regime. The elongation of the cluster systems of both galaxies is approximately aligned at large radii with the connecting axis of the two galaxies. We find specific frequencies within a radial range of 4 0 of S N= 3:0 2:0 for NGC 3268 and S N= 6:0 2:5 for NGC 3258. As a byproduct resulting from surveying our wide-field frames, we describe a strange absorption feature in the Antlia spiral galaxy NGC 3269, which we argue might be a tiny galactic dust cloud projected onto NGC 3269.