论文标题
Fermi检测到的CSS 3C 286的光谱分类，可变性和SED：无线电最低的NLS1银河系？
Spectroscopic classification, variability and SED of the Fermi-detected CSS 3C 286: the radio-loudest NLS1 galaxy?
论文作者
论文摘要
3C 286是射电天文学中众所周知的校准源。它也是在$γ$ -rays中检测到的极少数紧凑型陡峭光谱源（CSS）之一。在这里，我们执行详细的光谱和可变性分析，并介绍第一个准杂音的光学光学到X射线光谱能分布，以揭示物理机制，这些机制在不同的波长下占主导地位，并得出可靠的光源分类。我们研究的第一个主要结果揭示了在应用简单的宽线或狭窄的Seyfert 1（BLS1或NLS1）分类标准时，仅查看[OIII] -H $β$复杂的标准。 [OIII]和H $β$可以由相同的流出组件主导，在这种情况下，FWHM（H $β$）不是可靠的分类标准，并且固有或中间材料的灭绝可以使最高的H $β$组件无法检测到。 After careful combination of all information from UV-optical spectra along with multi-wavelength data, we confirm that 3C 286 can be classified as NLS1 galaxy, with line properties and SMBH mass (of order 10$^{8}$ M$_{\odot}$ and accreting near the Eddington limit) close to the BLS1 regime, making it an important borderline object.用$ swift $拍摄的准简单性SED显示了光学UV的急剧上升，这意味着存在具有EUV过量的强积聚磁盘成分，与发射线诊断一致。最后，我们报告了3C 286的X射线变异性的发现，并以喷气发射为主，并且至少要变量$ \ sim4 $。该结果建议在高分辨率无线电VLBI观察中使用3C 286作为无线电校准器时要谨慎行事。
3C 286 is a well-known calibrator source in radio astronomy. It is also one of very few compact steep-spectrum sources (CSS) detected in $γ$-rays. Here, we perform a detailed spectroscopic and variability analysis and present the first quasi-simultaneous optical to X-ray spectral energy distribution in order to reveal physical mechanisms which dominate its emission at different wavelengths, and arrive at a reliable optical source classification. The first main result of our study reveals several pitfalls when applying simple broad- or narrow-line Seyfert 1 (BLS1 or NLS1) classification criteria which only look at the [OIII]-H$β$ complex. [OIII] and H$β$ can be dominated by the same outflow components, in which case FWHM(H$β$) is no reliable classification criterion, and extinction by intrinsic or intervening material can make the highest-velocity H$β$ component undetectable. After careful combination of all information from UV-optical spectra along with multi-wavelength data, we confirm that 3C 286 can be classified as NLS1 galaxy, with line properties and SMBH mass (of order 10$^{8}$ M$_{\odot}$ and accreting near the Eddington limit) close to the BLS1 regime, making it an important borderline object. The quasi-simultaneous SED taken with $swift$ shows a sharp rise in the optical-UV, implying the presence of a strong accretion-disk component with EUV excess, consistent with emission-line diagnostics. Finally, we report the discovery of X-ray variability of 3C 286, plausibly dominated by jet emission, and variable by at least a factor $\sim4$. This result suggests to exercise caution when using 3C 286 as radio calibrator in high-resolution radio VLBI observations.
