标题： 斯皮策红外光谱对3CR射电星系和类星体的观测：检验统一模型方案 显示英文标题

标题： Spitzer IRS spectroscopy of 3CR radio galaxies and quasars: Testing the unified schemes

摘要： 利用斯皮策空间望远镜红外光谱仪（IRS），我们观测了七个强大的FR2射电星系和七个类星体。 这两个样本——星系和类星体——在各向同性178 MHz光度（\(10^\{26.5\}\) W/Hz < \(P_\{178\text\{MHz\}\}\) < \(10^\{29.5\}\) W/Hz）和红移范围（0.05 < z < 1.5）上具有可比性。 我们发现，对于这两个样本，在高激发线与低激发线的亮度比（[NeV] 14.3 μm / [NeII] 12.8 μm）以及高激发线与射电功率的亮度比（[NeV] 24.3\mu / \(P_\{178\text\{MHz\}\}\)）方面分布相似。这解决了关于类星体和射电星系之间表观差异的长期争议，支持了方向依赖的统一模型。 此外，大多数星系的[OIII] 500.7 nm / [OIV] 25.9 μm亮度比比类星体低一个数量级。 这表明，在强大的FR2星系中，中心窄线区（NLR）的光学发射基本上被吸收（\(A_V\) > 3），并且[OIII] 500.7 nm的光度不能作为各向同性的示踪剂来验证统一模型。 显示英文摘要

摘要： With the Spitzer Space Telescope Infrared Spectrograph (IRS) we have observed seven powerful FR2 radio galaxies and seven quasars. Both samples, the galaxies and the quasars, are comparable in isotropic 178 MHz luminosity (10^26.5 W/Hz < P 178MHz < 10^29.5 W/Hz) and in redshift range (0.05 < z < 1.5). We find for both samples similar distributions in the luminosity ratios of high- to low-excitation lines ([NeV] 14.3 mu / [NeII] 12.8 mu) and of high-excitation line to radio power ([NeV] 24.3 \mu / P 178MHz). This solves the long debate about the apparent difference of quasars and radio galaxies in favor of the orientation-dependent unified schemes. Furthermore, the luminosity ratio [OIII] 500.7 nm / [OIV] 25.9 mu of most galaxies is by a factor of ten lower than that of the quasars. This suggests that the optical emission from the central NLR is essentially absorbed (A_V} > 3) in the powerful FR2 galaxies and that the [OIII] 500.7 nm luminosity does not serve as isotropic tracer for testing the unified schemes.