arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.14004astro-ph.GA
收藏

NGC 4151的偏振光谱能量分布

The polarized spectral energy distribution of NGC 4151

F. Marin, J. Le Cam, E. Lopez-Rodriguez, M. Kolehmainen, B. L. Babler, M. R. Meade

备注：
8 pages, 4 figures, accepted for publication in MNRAS
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

NGC 4151是研究得最充分的塞弗特星系之一，在观测者的视线范围内没有强烈的遮蔽。这使得探测中央活动星系核（AGN）引擎与测光，光谱，混响映射或干涉测量。然而，NGC 4151的宽带偏振在过去一直没有得到很好的研究，尽管偏振测量比单独的光度测量或光谱学给了我们一个更清晰的AGN物理学视角。在本文中，我们编制了0.15 - 89.0 $μ$ m的总通量和偏振的NGC 4151从档案和新的数据，以检查在这个活动星系核的心脏工作的物理过程。我们证明，从光学到近红外（IR）波段，NGC 4151的偏振光谱显示出比总通量更蓝的幂律光谱指数，证实了光学厚，局部加热吸积流的存在，至少在其近红外发射半径。在吸收不透明度开始之前，在最短的紫外线（UV）波长处暂时发现了大气吸积结构的具体特征。否则，灰尘散射似乎是占主导地位的贡献者从近紫外线到近红外偏振光谱，叠加到一个较弱的电子组件。我们还确定了从近红外到中红外的偏振过程的变化，最有可能与从米氏散射到二向色吸收的过渡有关，这些吸收来自尘埃环面或窄线区域中对齐的尘埃颗粒。最后，我们介绍并讨论了NGC 4151在89 $μ$ m处的首次远红外偏振测量。

英文摘要：

NGC 4151 is among the most well-studied Seyfert galaxies that does not suffer from strong obscuration along the observer's line-of-sight. This allows to probe the central active galactic nucleus (AGN) engine with photometry, spectroscopy, reverberation mapping or interferometry. Yet, the broadband polarization from NGC 4151 has been poorly examined in the past despite the fact that polarimetry gives us a much cleaner view of the AGN physics than photometry or spectroscopy alone. In this paper, we compile the 0.15 -- 89.0 $μ$m total and polarized fluxes of NGC 4151 from archival and new data in order to examine the physical processes at work in the heart of this AGN. We demonstrate that, from the optical to the near-infrared (IR) band, the polarized spectrum of NGC 4151 shows a much bluer power-law spectral index than that of the total flux, corroborating the presence of an optically thick, locally heated accretion flow, at least in its near-IR emitting radii. Specific signatures from the atmosphere of the accretion structure are tentatively found at the shortest ultraviolet (UV) wavelengths, before the onset of absorption opacity. Otherwise, dust scattering appears to be the dominant contributor from the near-UV to near-IR polarized spectrum, superimposed onto a weaker electron component. We also identify a change in the polarization processes from the near-IR to the mid-IR, most likely associated with the transition from Mie scattering to dichroic absorption from aligned dust grains in the dusty torus or narrow-line region. Finally, we present and dicuss the very first far-infrared polarization measurement of NGC 4151 at 89 $μ$m.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑