Peering through the Dust: Evidence for a Supermassive Black Hole at the Nucleus of Centaurus A from VLT Infrared Spectroscopy
Peering through the Dust: Evidence for a Supermassive Black Hole at the Nucleus of Centaurus A from VLT Infrared Spectroscopy
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DOI：
10.1086/319445
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发表时间：
2000-11
期刊：
影响因子：
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通讯作者：
A. Marconi;A. Capetti;D. Axon;A. Koekemoer;D. Macchetto;E. Schreier
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作者：
A. Marconi;A. Capetti;D. Axon;A. Koekemoer;D. Macchetto;E. Schreier
我们使用ESO甚大望远镜的近红外光谱仪ISAAC来绘制星系中心20“处几个位置角度和位置的Cen A（NGC 5128）的速度场。电离和分子气体（Paβ，[Fe II]，Brγ和H2）的高空间分辨率（~0.″5）速度场不受激发效应或遮蔽的影响。我们确定了三个不同的运动学系统：（1）电离气体的旋转“核盘”，局限于内部2“，与HST/NICMOS成像所揭示的Paα特征相对应：（2）仅在H2中探测到的内径约为6”的环状系统，可能与其他作者在CO中探测到的100 pc尺度结构相对应;（3）星系势中旋转气体的正常伸展分量。核盘是围绕中心质量集中的开普勒旋转，暗的（M/L > 20 M偏转/LK），在数据的空间分辨率（R 15°）为MBH = 2 × 108 M偏转时呈点状。环状系统的特征可能是非圆运动;在H2位置-速度图中观察到的“8字形”图案可能为核棒的存在提供了运动学证据。
We used the near-infrared spectrometer ISAAC at the ESO Very Large Telescope to map the velocity field of Cen A (NGC 5128) at several position angles and locations in the central 20'' of the galaxy. The high spatial resolution (~0.″5) velocity fields from both ionized and molecular gas (Paβ, [Fe II], Brγ, and H2) are not compromised by either excitation effects or obscuration. We identify three distinct kinematical systems: (1) a rotating "nuclear disk" of ionized gas, confined to the inner 2'', the counterpart of the Paα feature previously revealed by HST/NICMOS imaging; (2) a ringlike system with a ~6'' inner radius detected only in H2 likely the counterpart of the 100 pc scale structure detected in CO by other authors; (3) a normal extended component of gas rotating in the galactic potential. The nuclear disk is in Keplerian rotation around a central mass concentration, dark (M/L > 20 M☉/LK☉) and pointlike at the spatial resolution of the data (R 15°) is MBH = 2 × 108 M☉. The ringlike system is probably characterized by noncircular motions; a "figure of 8" pattern observed in the H2 position-velocity diagram might provide kinematical evidence for the presence of a nuclear bar.