标题： 朝向M81核心的气体流动运动 显示英文标题

标题： Gas Streaming Motions towards the Nucleus of M81

摘要： 我们展示了塞弗特1型星系M81内部120x250pc^2区域的恒星和气体动力学，这些数据来自在基米尼北天文台使用GMOS积分场光谱仪获得的光学光谱，空间分辨率为10pc。 恒星速度场显示为圆周旋转，但在靠近小轴处观察到偏差，这可能归因于与核棒相关的恒星运动。 核心的恒星速度弥散度为162km/s，根据M_BH-sigma关系，这导致黑洞质量为M_BH=5.5x10^7M_sun。 气体动力学主要由非圆周运动主导，减去恒星速度场后，在星系的远侧显示出约-100km/s的蓝移，在近侧则有几个红移。 如果气体位于平面内，这些特征可以解释为向中心流动。 根据观测到的速度和流体几何结构，我们估计电离气体的质量流入速率为~4.0x10^-3M_sun/年，这与维持M81 LINER核所需的吸积率相当。 我们还应用了主成分分析（PCA）技术到我们的数据中，结果显示在核附近约50pc范围内存在一个旋转的核气体盘以及一个紧致的外流，大约垂直于该盘。 PCA结合观测到的气体速度场表明，核盘由在星系平面内循环的气体供给。 外流的存在得到了射电观测中相似取向的紧致喷流的支持，以及[OI]\Halpha 线比的增强，这可能是由于射电喷流对核周围气体的冲击激发所致。 通过这些观测，我们因此解析了M81核周围的供能过程——通过核盘和观测到的气体流入，以及反馈过程——通过外流。 显示英文摘要

摘要： We present stellar and gaseous kinematics of the inner 120x250pc^2 of the Liner/Seyfert 1 galaxy M81, from optical spectra obtained with the GMOS integral field spectrograph on the Gemini North telescope at a spatial resolution of 10pc. The stellar velocity field shows circular rotation but deviations are observed close to the minor axis which can be attributed to stellar motions possibly associated to a nuclear bar. The stellar velocity dispersion of the bulge is 162km/s leading to a black hole mass of M_BH=5.5x10^7M_sun based on the M_BH-sigma relationship. The gas kinematics is dominated by non-circular motions and the subtraction of the stellar velocity field reveals blueshifts of ~-100km/s on the far side of the galaxy and a few redshifts on the near side. These characteristics can be interpreted in terms of streaming towards the center if the gas is in the plane. On the basis of the observed velocities and geometry of the flow, we estimate a mass inflow rate in ionized gas of ~4.0x10^-3M_sun/year, which is of the order of the accretion rate necessary to power the LINER nucleus of M81. We have also applied the technique of Principal Component Analysis (PCA) to our data, which reveals the presence of a rotating nuclear gas disk within ~50pc from the nucleus and a compact outflow, approximately perpendicular to the disk. The PCA combined with the observed gas velocity field shows that the nuclear disk is being fed by gas circulating in the galaxy plane. The presence of the outflow is supported by a compact jet seen in radio observations at a similar orientation, as well as by an enhancement of the [OI]\Halpha line ratio, probably resulting from shock excitation of the circumnuclear gas by the radio jet. With these observations we are thus resolving both the feeding -- via the nuclear disk and observed gas inflow, and the feedback -- via the outflow, around the nucleus of M81.