The Nature of LINERs
The Nature of LINERs
复制标题
LINER 的本质
DOI：
10.1086/308388
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
J. Shields
中科院分区：
文献类型：
--
作者：
A. Alonso;M. Rieke;G. Rieke;J. Shields
我们给出了一个由9个星系组成的样本的J带(1.15-1.35μm)光谱，这些星系显示了一定程度的线型活动(经典线型、弱[O-I]线型和过渡天体)，并对其中一些星系进行了H带谱分析。仔细地减去恒星连续体，我们就可以得到可靠的[Fe II]1.2567μm/paβ线比。我们得出的结论是，仅凭[Fe II]1.2567μm/paβ线比很难区分不同类型的线团(即被恒星连续体光电离或被活动星系核光离)。许多衬里的发射线特性可以用老化的星暴来解释。用单星温度T*=38000K光致电离的富金属HⅡ区分量加上超新星残留物(SNR)分量的模型再现了这些谱线的光谱线比。[Fe II]线主要是由星暴和以星暴为主的衬线中的SNR产生的激波激发的，而PAβ则跟踪被大质量年轻恒星电离的H II区域。信噪比对总发射线光谱的贡献受[Fe II]1.2567μm/paβ谱线比的限制。尽管我们的老化星暴模型只受这些红外线的限制，但它们也一致地解释了星系的光谱。通过预测电离光度(Lion)与超新星速率(SNR)之比Lion/(SNr)的时间依赖关系，验证了线性星暴的联系。我们预测了恒星爆发相对于以恒星爆发为主的线条(老化的恒星爆发)的相对数量，并表明这与对附近星系的调查结果大致一致。
We present J-band (1.15-1.35 μm) spectroscopy of a sample of nine galaxies showing some degree of LINER activity (classical LINERs, weak-[O I] LINERs, and transition objects), together with H-band spectroscopy for some of them. A careful subtraction of the stellar continuum allows us to obtain reliable [Fe II] 1.2567 μm/Paβ line ratios. We conclude that different types of LINERs (i.e., photoionized by a stellar continuum or by an active galactic nucleus) cannot be easily distinguished based solely on the [Fe II] 1.2567 μm/Paβ line ratio. The emission-line properties of many LINERs can be explained in terms of an aging starburst. The optical line ratios of these LINERs are reproduced by a model with a metal-rich H II region component photoionized with a single stellar temperature T* = 38,000 K, plus a supernova remnant (SNR) component. The [Fe II] line is predominantly excited by shocks produced by SNRs in starbursts and starburst-dominated LINERs, while Paβ tracks H II regions ionized by massive young stars. The contribution from SNRs to the overall emission-line spectrum is constrained by the [Fe II] 1.2567 μm/Paβ line ratio. Although our models for aging starbursts are constrained only by these infrared lines, they consistently explain the optical spectra of the galaxies also. The LINER-starburst connection is tested by predicting the time dependence of the ratio of the ionizing luminosity (Lion) to the supernova rate (SNr), Lion/(SNr). We predict the relative number of starbursts to starburst-dominated LINERs (aging starbursts) and show that it is in approximate agreement with survey findings for nearby galaxies.