What produces the extended LINER-type emission in the NUGA galaxy NGC 5850?
What produces the extended LINER-type emission in the NUGA galaxy NGC 5850?
复制标题
是什么在 NUGA 星系 NGC 5850 中产生扩展的 LINER 型发射？
DOI：
10.1051/0004-6361/201322009
复制
发表时间：
2013
影响因子：
6.5
通讯作者：
S. Fischer
中科院分区：
文献类型：
--
作者：
M. Bremer;J. Scharwachter;A. Eckart;M. Valencia;J. Zuther;F. Combes;S. García;S. Fischer
低电离核发射区（LINER）星系在活动星系核（AGN）图像中的作用一直存在争议。目前还不清楚它们是否在低吸积模式下拥有活动星系核，或者它们是否根本不活跃，而是由其他电离机制（即激波、风/外流或后渐近巨星分支（p-AGB）恒星群的光电离）主导。探测到扩展的类LINER辐射通常被认为是恒星成分电离的证据，但这并不是毫无争议的。我们进行了光学积分场光谱观测的中心约。4kpc的NGC 5850使用VIMOS在VLT，它提供了气体排放和恒星连续空间分辨光谱。我们推导和分析发射线和运动地图。我们发现NGC 5850的中心几千秒差距主要由扩展LINER类发射。对电离参数敏感的发射线比率随到核的径向距离而增加。因此，NGC 5850的扩展LINER类辐射主要来自于分布的电离源，可能是p-AGB上的恒星。类LINER区域被归类为"复合"的发射所包围，这可能是由于类LINER电离模式和低水平星星形成的光电离的混合物。在21 "x19"的视场中有两个恒星形成区。其中之一是位于大约在环周围的运动解耦的核心。第二个是接近核，是一个区域的发射线比率减少径向向外取向的起源。我们发现星际气体有陡峭的速度梯度和复杂的运动形态，可能是由不平衡（m = 1）的气体分布的区域。向中心的气体流入似乎是可能的。
(Abridged) The role of low ionization nuclear emission region (LINER) galaxies within the picture of active galactic nuclei (AGN) has been controversial. It is still not clear whether they host an AGN in a low accretion mode, or whether they are not active at all but dominated by alternative ionization mechanisms, namely shocks, winds/outflows, or photoionization by a post asymptotic giant branch (p-AGB) stellar population. The detection of extended LINER-like emission was often taken as evidence of ionization by stellar components but this has not been undisputed. We performed optical integral field spectroscopic observations on the central approx. 4 kpc of NGC 5850 using VIMOS at the VLT, which provides spatially-resolved spectra for the gas emission and the stellar continuum. We derive and analyse emission line and kinematic maps. We find the central few kpc of NGC 5850 to be dominated by extended LINER-like emission. The emission-line ratios that are sensitive to the ionization parameter increase with radial distance to the nucleus. Therefore, the extended LINER-like emission in NGC 5850 is dominated by ionization from distributed ionization sources, probably by stars on the p-AGB. The LINER-like region is surrounded by emission that is classed as 'composite', likely due to a mixture of a LINER-like ionization pattern and photoionization by low-level star formation. Two star-forming regions are present in the 21"x19" field of view. One of them is located approximately in the ring surrounding the kinematically decoupled core. The second one is close to the nucleus and is the origin of a region of decreased emission line ratios oriented radially outwards. We find the interstellar gas to have areas of steep velocity gradients and a complex kinematic morphology, probably caused by the lopsided (m=1) distribution of the gas. The inflow of gas toward the center appears possible.
发光合并星系的“引擎”被精确定位
DOI：
--
发表时间：
--
期刊：
影响因子：
--
作者：
通讯作者：
--