Extended gas in Seyfert galaxies: near-infrared observations of 15 active nuclei
Extended gas in Seyfert galaxies: near-infrared observations of 15 active nuclei
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塞弗特星系中的扩展气体：15 个活动核的近红外观测
DOI：
10.1046/j.1365-8711.2000.03614.x
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发表时间：
2000
影响因子：
4.8
通讯作者：
U.S.A.
中科院分区：
文献类型：
--
作者：
C. Winge;T. Storchi;M. Ward;Andrew S. Wilson IF;Brazil.;U. Leicester;U.K.;U. Maryland;Stsci;U.S.A.
摘要 介绍了对 15 个 Seyfert 星系和 NGC 5253 星暴核样本的低分辨率 OR 250U 近红外长缝光谱的分析结果，该光谱同时覆盖 I、J、H 和 K 波段。赛弗特星系被选择为在光学中呈现“线性”或锥状高激发发射线，很可能是由尘埃分子环面对中心源的辐射进行准直而产生的。我们的目标是寻找这个环面的特征，并研究气体分布、激发和红化。检测到的最强发射线通常是 He i 1.083mm 和 [S iii]l 9532，其次是 Pab。在某些情况下，还可以看到[Fe ii] 1.26和1.64mm。在为五个星系获得的一些高分辨率光谱中检测到了 [Fe ii] 1.26mm 和 H2 va 1 2 0 S(1)。在大多数情况下，发射线在空间上延伸，我们使用 [Fe ii]/Pab 比率作为 Mrk 573、NGC 1386 和 NGC 7582 中气体激发的量度。发现该比率的值在 1.5 到 6 之间，表明某些区域中 [Fe ii] 受到 X 射线或冲击波的激发。在三个 Seyfert 1 星系中观察到了广泛的许可线。 NGC 1365 中的核 Pab 以及 Mrk 573 中可能的核 Brg 也很广泛。通过对光谱中连续 OJ 2 HU 和 OH 2 KU 颜色空间分布的分析，我们发现在观察到的大多数 Seyfert 2 中，原子核的颜色比附近凸起的颜色更红。与包括尘埃和恒星发射在内的模型的比较表明，热OT、1000 KU尘埃发射在NGC 1365、NGC 2110、NGC 3281、NGC 7582和ESO 362-G18中的核连续谱中占主导地位。在 NGC 1386、5643 和 5728 中，主要贡献者是底层恒星群，再加上一些前景变红和/或较冷的尘埃排放。在少数情况下，核两侧的 OJ 2 HU 颜色相差 0.3-0.8 星等，我们将这种效应解释为部分是由于当地恒星种群的差异以及可能的消光梯度造成的。
ABSTRA C T Results from an analysis of low-resolution OR , 250U near-infrared long-slit spectra covering simultaneously the I, J, H and K bands, for a sample of 15 Seyfert galaxies and the NGC 5253 starburst nucleus, are presented. The Seyfert galaxies were selected as presenting ‘linear’ or cone-like high-excitation emission lines in the optical, most probably arising from the collimation of the radiation of the central source by a dusty molecular torus. Our goal was to look for signatures of this torus, and to investigate the gaseous distribution, excitation and reddening. The strongest emission lines detected are usually He i 1.083mm and [S iii]l 9532, followed by Pab. In some cases, [Fe ii] 1.26 and 1.64mm are also seen. [Fe ii] 1.26mm and H2 va 1 2 0 S(1) are detected in some of the higher resolution spectra obtained for five galaxies. The emission lines are spatially extended in most cases, and we have used the [Fe ii]/Pab ratio as a measure of the gaseous excitation in Mrk 573, NGC 1386 and NGC 7582. Values for this ratio between 1.5 and 6 are found, suggesting excitation of [Fe ii] by X-rays or shock waves in some regions. Broad permitted lines are observed in three Seyfert 1 galaxies. Nuclear Pab in NGC 1365 and possibly nuclear Brg in Mrk 573 are also broad. From analysis of the spatial distribution of the continuumOJ 2 HU andOH 2 KU colours derived from our spectra, we find redder colours for the nucleus than for the nearby bulge in most of the Seyfert 2s observed. Comparison with models including emission from dust and stars shows that hot OT , 1000 KU dust emission dominates the nuclear continuum in NGC 1365, NGC 2110, NGC 3281, NGC 7582 and ESO 362-G18. In NGC 1386, 5643 and 5728 the main contributor is the underlying stellar population, combined with some foreground reddening and/or cooler dust emission. In a few cases, theOJ 2 HU colours on opposite sides of the nucleus differ by 0.3‐0.8 mag, an effect that we interpret as partly resulting from differences in the local stellar population, and possibly extinction gradients.