Nuclear molecular outflow in the Seyfert galaxy NGC 3227-猫眼课题宝

DOI：

10.1051/0004-6361/201935431

发表时间：

2019-06

期刊：

Astronomy & Astrophysics

影响因子：

6.5

通讯作者：

中科院分区：

物理与天体物理2区

文献类型：

作者：

A. Alonso-Herrero;S. García-Burillo;M. Pereira-Santaella;R. Davies;F. Combes;M. Vestergaard;S. Raimundo;A. Bunker;T. Díaz-Santos;P. Gandhi;I. García-Bernete;E. Hicks;S. Hönig;L. Hunt;M. Imanishi;T. Izumi;N. Levenson;W. Maciejewski;C. Packham;C. R. Almeida;C. Ricci;D. Rigopoulou;P. Roche;D. Rosario;M. Schartmann;A. Usero;Martin P. Ward

阿尔马观测揭示了迄今为止研究过的少数几个塞弗特和低光度活动星系核中特征尺寸为15 - 40 pc的核尘埃分子盘或环面。这些结构通常在形态学和运动学上与宿主星系盘分离。本文介绍了阿尔马对附近的塞弗特1.5星系NGC 3227的CO（2-1）和CO（3-2）分子气体跃迁以及相关的（亚）毫米连续谱的观测结果，角分辨率为0.085 − 0.21″（7-15 pc）。在大尺度上，冷分子气体表现出圆周运动以及与大尺度棒相关的几百秒差距尺度上的流运动。我们拟合核阿尔马1.3毫米发射与未解决的组件和扩展组件。850 μm的辐射至少有两个扩展分量，一个沿着核盘的长轴，另一个沿着电离锥的轴。在中心区域（1″ <$73 pc）的分子气体显示了几个CO团簇，具有复杂的运动学，似乎是由非圆运动为主。虽然我们不能最终证明存在一个翘曲的核盘，我们也检测到非圆形运动沿着运动学短轴。它们的视速度达到v − vsys = 150 − 200 km s−1。假设径向运动是在星系的平面，我们解释为一个核分子外流，由于分子气体在宿主星系，是由AGN风夹带。在活动星系核东北和西南方向投影距离为30秒差距的情况下，我们得到的分子外流速率分别为5 M yr−1和0.6 M yr−1。在活动星系核的位置，我们估计分子气体的质量为5 × 105 M，内部15 pc的等效平均柱密度N（H2）= 2 − 3 × 1023 cm−2。NGC 3227的核CO（2-1）和CO（3-2）分子气体和亚毫米连续谱发射与经典的致密环面不相似。相反，这些辐射延伸了几十秒差距，似乎与宿主星系盘中的环核环有关，就像在其他局部活动星系核中发现的那样。

ALMA observations have revealed nuclear dusty molecular disks or tori with characteristic sizes 15−40 pc in the few Seyferts and low -luminosity AGN that have been studied so far. These structures are generally decoupled both morphologically and kinematically from the host galaxy disk. We present ALMA observations of the CO(2–1) and CO(3–2) molecular gas transitions and associated (sub-) millimeter continua of the nearby Seyfert 1.5 galaxy NGC 3227 with angular resolutions 0.085 − 0.21″ (7–15 pc). On large scales, the cold molecular gas shows circular motions as well as streaming motions on scales of a few hundred parsecs that are associated with a large-scale bar. We fit the nuclear ALMA 1.3 mm emission with an unresolved component and an extended component. The 850 μm emission shows at least two extended components, one along the major axis of the nuclear disk, and the other along the axis of the ionization cone. The molecular gas in the central region (1″ ∼ 73 pc) shows several CO clumps with complex kinematics that appears to be dominated by noncircular motions. While we cannot conclusively demonstrate the presence of a warped nuclear disk, we also detected noncircular motions along the kinematic minor axis. They reach line-of-sight velocities of v − vsys = 150 − 200 km s−1. Assuming that the radial motions are in the plane of the galaxy, we interpret them as a nuclear molecular outflow due to molecular gas in the host galaxy that is entrained by the AGN wind. We derive molecular outflow rates of 5 M⊙ yr−1 and 0.6 M⊙ yr−1 at projected distances of up to 30 pc to the northeast and southwest of the AGN, respectively. At the AGN location we estimate a mass in molecular gas of 5 × 105 M⊙ and an equivalent average column density N(H2) = 2 − 3 × 1023 cm−2 in the inner 15 pc. The nuclear CO(2–1) and CO(3–2) molecular gas and submillimeter continuum emission of NGC 3227 do not resemble the classical compact torus. Rather, these emissions extend for several tens of parsecs and appear connected with the circumnuclear ring in the host galaxy disk, as found in other local AGN.

Nuclear molecular outflow in the Seyfert galaxy NGC 3227

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