低光度活动星系核的射电干涉阵观测研究

发布时间：2018-05-12 06:28

本文选题：超大质量黑洞 + 射电干涉　；参考：《南京大学》2017年博士论文

【摘要】：超大质量黑洞的吸积与反馈活动是天体物理中重要的物理过程。超大质量黑洞作为活动星系核的引擎,通过吸积周围的物质将引力能转换为辐射能,通过喷流、外流或者风的形式向星际介质反馈机械能。寄主星系和其中心黑洞无时不进行着相互作用共同演化。因此,了解黑洞的吸积和反馈的物理过程是了解星系的形成与演化中重要的一环。但目前对超大质量黑洞的吸积和反馈的物理过程并不清楚,这也一直是天体物理中的关键问题。近几十年来,对于超大质量黑洞的的观测取得了很多进展,例如：通过近邻星系的巡天发现低光度活动星系核在近邻活动星系核的样本中占有很大的比例；在这些低光度活动星系核中常常能观测到核区致密的X射线和射电辐射；以及发现这些源常常在多波段存在光变。根据黑洞的观测性质(多波段观测结果组成的宽带能谱分布,磁场等),人们逐步建立了黑洞吸积在辐射模式和喷流史瓦西模式下不同的理论框架。然而,这一框架中依旧有很多关键问题没有得到解决,例如：是否超大质量黑洞的射电辐射总有喷流的贡献,或者是否喷流的辐射主导着黑洞在射电波段的辐射？是否喷流进行地方向会在演化中发生变化？以及在黑洞附近产生耀变的物理意义是什么？本论文通过对距离很近的三个星系M31,M 32和M 104中心的低光度活动星系核的高分辨率的射电干涉阵的观测,讨论了以下两个问题：1)吸积极不活跃的超大质量黑洞的射电辐射性质；2)盘星系中喷流对星际介质的能量反馈。对这两个问题的研究可以给理论模型更多实际例子上的限制,从而进一步了解黑洞活动的物理过程。第二章中,我们通过使用Karl G. Jansky Very Large Array (JVLA)甚大阵射电干涉仪对M 31*进行了多历元的多波段的pc尺度的观测。我们分析了这些连续谱观测的结果,首次在10,15和20 GHz频率探测到致密的射电核,并且看到在6 GHz的图像中的致密的射电核周围存在沿着不同方向的延展结构。在2011到2012年问多次的观测,看到了M 31*的流量在6 GHz频率的流量变化,最短变化时标在6小时内出现了近40%的变化幅度,说明光变可能来自～20个史瓦西半径处。通过我们在多频率的观测结果,我们建立了6到20 GHz的谱能量分布,拟合(Sv,∝ α)得到谱指数α～-0.45,并由此推断射电辐射很可能是由喷流主导的。第三章中,M 32作为本星系群中的一个椭圆星系,其中心的超大质量黑洞是最近的超大的质量黑洞之一。我们利用JVLA干涉阵第一次探测到位于M 32星系核中心的一个致密射电源。这个射电源在中心频率6.6 GHz的流量密度是～47.3±6.1 μJy。我们讨论了这个射电源起源的可能性,认为它起源于超大质量黑洞的射电辐射。同时我们利用Chandra和XMM-Newton的X射线数据研究了这个超大质量黑洞的X射线辐射性质。第四章中,M 104 (NGC 4594)是一个大质量的的早型旋涡星系,也被称作草帽星系,在其中心存在一个原型的低光度活动星系核。我们使用JVLA对M104在多波段进行了不同分辨率的连续谱观测以获得其喷流在不同物理尺度的特征。通过分析认为M 104的kpc尺度的延展很可能来自pc尺度的射电喷流。并且发现kpc尺度喷流的方向与pc尺度喷流的方向有差异,暗示了喷流在传播过程中发生偏折,或者不同尺度的喷流产生自中心黑洞的不同活跃期；我们通过定量测量了kpc尺度喷流的磁压,发现其与星际热气体的压强相当,暗示了喷流在传播过程中的机械功对气体注入了可观的能量。第五章中,我们主要介绍了对本论文工作的总结以及展望。
[Abstract]:The accretion and feedback activity of a supermassive black hole is an important physical process in astrophysics. As the engine of the active galactic nucleus, the supermassive black hole converts the gravitational energy into radiant energy by accretion of the surrounding material, and feedback the mechanical energy to the interstellar medium by the form of jet, outflow or wind. The host galaxy and its central black hole are all the time. The physical process of understanding the accretion and feedback of a black hole is an important link in understanding the formation and evolution of galaxies. However, the physical process of the accretion and feedback of a supermassive black hole is not clear at present. It is also a key problem in astrophysics. In recent decades, the supermassive black hole has been found. A lot of progress has been made, for example: a large proportion of the low photometric active galactic nuclei in the near adjacent active galactic nuclei is found through a cruise of near neighbor galaxies; the dense X rays and radio radiation of the nuclear region are often observed in these low photometric active galactic nuclei; and it is found that these sources often exist in multiple bands. According to the observational properties of the black hole (the broadband energy spectrum distribution, magnetic field, etc.), a different theoretical framework for the black hole accretion in the radiation pattern and the jet schwarzsche model is gradually established. However, there are still many key problems in this framework, such as whether the supermassive black hole is shot. Electrical radiation always has the contribution of jet flow, or whether or not the radiation of the jet dominates the radiation of the black hole in the radio band? Is the jet changing in the evolution? And what is the physical significance of the variation near the black hole? This paper passes the low luminosity stars of the three galaxies, M31, M 32, and M 104, which are very close to the distance. The observation of the high resolution radio interference array of the nucleus discusses the following two problems: 1) the radio radiation properties of the extremely inactive supermassive black holes; 2) the energy feedback of the jet on the interstellar medium in the disk galaxy. The study of these two problems can give more practical examples of the theoretical model, thus further understanding the black. In the second chapter, we observe M 31* by using Karl G. Jansky Very Large Array (JVLA) very large array radio interferometer to observe M 31* multispectral PC scales. We analyze the results of these continuous spectral observations, detect the dense radio nuclei for the first time in 10,15 and 20 GHz frequencies, and see in 6 The dense radio nucleus in the Z image has a ductile structure along different directions. From 2011 to 2012, the flow of the M 31* flow at 6 GHz frequency changes, and the shortest change is marked in 6 hours, which shows that the change may come from the 20 schwarzschi radius. The spectral energy distribution of 6 to 20 GHz is established by multi frequency observations. The spectral exponent alpha to -0.45 is obtained by fitting (Sv), and it is concluded that radio radiation is likely to be dominated by the jet. In the third chapter, M 32 is an elliptical galaxy in the cluster of galaxies, and the supermassive black hole in the center is one of the most recent supermassive black holes. We used the JVLA interference array for the first time to detect a dense radio source at the center of the M 32 nucleus. The discharge density of the source at the center frequency 6.6 GHz is 47.3 + 6.1 mu Jy.. We discuss the possibility of the origin of the emitter source. It is believed that it originated from the radio radiation of the supermassive black hole. At the same time, we use Chandra and XMM. The X ray data of -Newton studies the X ray radiation properties of the supermassive black hole. In the fourth chapter, M 104 (NGC 4594) is a large mass of early vortex galaxies, also known as the straw hat galaxies, and there is a prototype low photometric active galactic nucleus in its center. We have made JVLA to M104 in multiple bands with different resolutions. It is believed that the extension of the KPC scale of M 104 is likely to come from the radio jet of the PC scale through analysis, and it is found that the direction of the KPC scale jet is different from the direction of the PC scale jet, suggesting that the jet is deflected during the propagation process, or the jet of different scales is produced from the jet. At the different active stages of the central black hole, we measured the magnetic pressure of the KPC scale jet quantitatively, and found that it was equal to the pressure of the interstellar hot gas, suggesting that the mechanical work of the jet in the process of propagation has injected considerable energy into the gas. In the fifth chapter, we mainly introduce the summary and Prospect of the work in this paper.

【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P161;P152

【参考文献】