DISCOVERY OF A GIANT STELLAR TIDAL STREAM AROUND THE DISK GALAXY NGC 4013
DISCOVERY OF A GIANT STELLAR TIDAL STREAM AROUND THE DISK GALAXY NGC 4013
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DOI：
10.1088/0004-637x/692/2/955
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发表时间：
2008-01
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影响因子：
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通讯作者：
D. Martinez-Delgado;D. Martinez-Delgado;M. Pohlen;M. Pohlen;R. J. Gabany;S. Majewski;J. Peñarrubia;C. Palma;C. Palma;C. Palma
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作者：
D. Martinez-Delgado;D. Martinez-Delgado;M. Pohlen;M. Pohlen;R. J. Gabany;S. Majewski;J. Peñarrubia;C. Palma;C. Palma;C. Palma
我们报告了在边缘螺旋星系NGC 4013周围发现的巨大的环状恒星结构。这一弧形特征从中心向东北方向延伸6′（投影距离为26千秒差距），从盘面延伸3′（投影距离为12千秒差距）;在盘面的西南侧也有可能相关的特征，延伸至4′（投影距离为17千秒差距）。这种低表面亮度（μR = 27.0+0.3−0.2 mag arcsec−2）结构的探测在三个不同望远镜的三个独立数据集中得到了独立的证实。尽管其真正的三维几何形状尚不清楚，但该结构的天空投影形态显示出与以低倾斜（25°）运动的矮卫星的恒星潮汐流的边缘投影视图的理论预测相匹配。，近圆形轨道。利用佩纳鲁比亚和同事最近建立的银河系麒麟座潮汐流模型作为模板，我们发现这个祖先系统可能是一个初始质量为6 × 108 M的星系，其目前的位置和最终的命运是未知的。根据这一模拟，潮汐流的年龄可能约为2.8Gyr。我们的研究结果表明，NGC 4013，以前被认为是一个典型的孤立的盘星系，尽管有一个最突出的H i翘曲检测到迄今为止，可能实际上遭受了最近的轻微合并。这一发现突出了未受干扰的磁盘在高表面亮度水平的光学，但扭曲的H i地图实际上可能揭示了复杂的签名最近吸积事件在深测光调查。
We report the discovery of a giant, looplike stellar structure around the edge-on spiral galaxy NGC 4013. This arcing feature extends 6′ (∼26 kpc in projected distance) northeast from the center and 3′ (≃12 kpc) from the disk plane; likely related features are also apparent on the southwest side of the disk, extending to 4′ (∼17 kpc). The detection of this low surface brightness (μR = 27.0+0.3−0.2 mag arcsec−2) structure is independently confirmed in three separate datasets from three different telescopes. Although its true three-dimensional geometry is unknown, the sky-projected morphology of this structure displays a match with the theoretical predictions for the edge-on, projected view of a stellar tidal stream of a dwarf satellite moving in a low inclined (≃25°), nearly circular orbit. Using the recent model of the Monoceros tidal stream in the Milky Way by Peñarrubia and colleagues as a template, we find that the progenitor system may have been a galaxy with an initial mass 6 × 108 M☉, whose current position and final fate are unknown. According to this simulation, the tidal stream may be approximately ∼2.8 Gyr of age. Our results demonstrate that NGC 4013, previously considered a prototypical isolated disk galaxy in spite of having one of the most prominent H i warps detected thus far, may have in fact suffered a recent minor merger. This discovery highlights that undisturbed disks at high surface brightness levels in the optical but warped in H i maps may in fact reveal complex signatures of recent accretion events in deep photometric surveys.