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arXiv 0903.3468astro-ph.GA
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后星爆+ AGN星系SDSS J230743 .41+152558.4的内部动力学和恒星星族

Internal Kinematics and Stellar Populations of the Poststarburst+AGN Galaxy SDSS J230743.41+152558.4

I. Chilingarian, S. De Rijcke, P. Buyle

摘要:

我们提出了第一个三维光谱观测附近的HI检测poststarburst,或E+A,星系,SDSS J230743.41+152558.4,在ESO VLT的VIMOS IFU摄谱仪获得。使用NBursts全光谱拟合技术,我们推导出恒星运动学,年龄和金属丰度的2-3个半光半径的地图。我们的分析揭示了一个大规模的快速旋转盘(v_circ = 300 km/s),具有正的年龄梯度(0.6 - 1.5 Gyr)和一个非常富金属的中心区域([Fe/H]=+0.25 dex)。如果合并或相互作用是引发恒星暴的原因,那么这个未受干扰的圆盘的存在表明与富含气体的卫星的小合并是最合理的选择,而不是破坏性的大合并。我们发现了LINER或AGN存在的光谱证据。这是截断星爆的反馈机制的重要线索。目前观察到的静止阶段很可能是银河系生命中的一个暂时插曲。SDSS J230743.41+152558.4富含气体,可能会重新开始形成恒星,在最终稳定在红色序列之前再次变成蓝色。

英文摘要:

We present the first 3D spectroscopic observations of a nearby HI detected poststarburst, or E+A, galaxy, SDSS J230743.41+152558.4, obtained with the VIMOS IFU spectrograph at ESO VLT. Using the NBursts full spectral fitting technique, we derive maps of stellar kinematics, age, and metallicity out to 2-3 half-light radii. Our analysis reveals a large-scale rapidly rotating disc (v_circ = 300km/s) with a positive age gradient (0.6 to 1.5 Gyr), and a very metal-rich central region ([Fe/H]=+0.25 dex). If a merger or interaction is responsible for triggering the starburst, the presence of this undisturbed disc suggests a minor merger with a gas-rich satellite as the most plausible option, rather than a disruptive major merger. We find spectroscopic evidence for the presence of a LINER or AGN. This is an important clue to the feedback mechanism that truncated the starburst. The presently observed quiescent phase may well be a temporary episode in the galaxy's life. SDSS J230743.41+152558.4 is gas-rich and may restart forming stars, again becoming blue before finally settling at the red sequence.

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