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arXiv 1407.7615astro-ph.HE
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BL Lacertae天体的光学观测

An Optical View of BL Lacertae Objects

Renato Falomo, Elena Pian, Aldo Treves

摘要:

BL Lac天体是活动核,位于大质量椭圆星系中,其发射主要由与视线紧密对齐的相对论性喷流控制。这意味着存在一个母源人口与错位喷流,已被确定与低功率radiogaleography。BL Lac的光谱,在整个电磁范围内以非热发射为主,加上明亮紧凑的无线电核心,高光度,在所有频率下快速和大幅度的通量变化和强极化,使这些来源成为高能天体物理学的最佳实验室。这一类别最显著的特征是谱线的弱或缺失,这在历史上阻碍了对它们性质的识别,并且此后被证明是确定它们距离的障碍。在本文中,我们审查的主要观测事实,有助于目前的基本解释这类活动星系。我们概述了BL Lac天体研究领域的历史及其人口,因为它出现了多波长的调查。与射电、X射线和伽马射线频率的通量变化和偏振特性相比,本文总结了这些特性以及宿主星系、它们的环境和中心黑洞质量的现有知识。我们专注于此审查的光学观测,发挥了至关重要的作用,在早期阶段的BL湖的研究,尽管广泛的无线电,X射线,最近伽马射线观测,可以代表未来的主要贡献揭开这些来源的起源。特别是,它们可以对长期争论的这类活动星系核的宇宙演化问题以及超大质量黑洞的形成与相对论性喷流之间的联系提供坚定的结论。

英文摘要:

BL Lac objects are active nuclei, hosted in massive elliptical galaxies, the emission of which is dominated by a relativistic jet closely aligned with the line of sight. This implies the existence of a parent population of sources with a misaligned jet, that have been identified with low-power radiogalaxies. The spectrum of BL Lacs, dominated by non-thermal emission over the whole electromagnetic range, together with bright compact radio cores, high luminosities, rapid and large amplitude flux variability at all frequencies and strong polarization make these sources an optimal laboratory for high energy astrophysics. A most distinctive characteristic of the class is the weakness or absence of spectral lines, that historically hindered the identification of their nature and ever thereafter proved to be a hurdle in the determination of their distance. In this paper we review the main observational facts that contribute to the present basic interpretation of this class of active galaxies. We overview the history of the BL Lac objects research field and their population as it emerged from multi-wavelength surveys. The properties of the flux variability and polarization, compared with those at radio, X-ray and gamma-ray frequencies, are summarized together with the present knowledge of the host galaxies, their environments, and central black hole masses. We focus this review on the optical observations, that played a crucial role in the early phase of BL Lacs studies, and, in spite of extensive radio, X-ray, and recently gamma-ray observations, could represent the future major contribution to the unveiling of the origin of these sources. In particular they could provide a firm conclusion on the long debated issue of the cosmic evolution of this class of active galactic nuclei and on the connection between formation of supermassive black holes and relativistic jets.

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。

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