活动星系核与寄主星系协同演化的多波段研究:超大质量黑洞吸积反馈

It is a hot topic in astrophysics that how active galactic nuclues (AGN) co-evolves with its host galaxy. A majotity of the current theoretical studies suggest that the feedback from the central supermassive blackhole potentially plays an important role in the coevolution issue, although the mechanism and evolution of the feedback is still poorly understood at present. Basing upon the phenomenological coevolution scenario revealed in previous studies, the proposed project is to perform multi-wavelength studies on the evolution of the feedback with the host galaxy , which is not only essential for revealing the mechanism of feedback , but also for establishing a theoretical model of co-evolution between AGNs and their host galaxies. The key point of the project is to search for evidence of evolution of feedback with host galaxy in type I AGNs in the observational ground, which is a hard task because the light from host galaxy is typically overwhelmed by the intense radiation from central supermassive blackhole. In the project, the difficulty is attempted to be conquered by using multiwavelength observational data as follows: 1) the relationship between the outflow and soft/hard X-ray energy spectral index; 2) the relationship between outflow and star formation activity as traced by middle-far infrared color and by infrared/optical narrow-line ratios; 3) the relationship between outflow and the stellar population age that is directly measured from the optical spectra in partially obscured AGNs and ultraviolet-variability selected AGNs.

活动星系核与寄主星系的协同演化是天体物理中的热点和难点问题。绝大部分现有的星系演化模型都注意到了黑洞吸积反馈在协同演化中的重要作用，但是在反馈的具体物理机制、随演化进程的变化等方面都还没有定论或缺乏系统的观测证据。本项目是在之前唯像研究的基础上，结合多波段观测，研究反馈随寄主星系的演化，从反馈的角度探索协同演化唯像图像背后的物理机制，对于揭示反馈的物理机制和从唯像图像出发建立协同演化的理论模型都具有重要意义。项目的研究重点是在I型活动星系核中寻找外向流随寄主星系协同演化的观测证据，难点是如何在I型活动星系核中克服核心与寄主星系光度的高反差来测量寄主星系的性质。为此，拟从多波段的角度来开展以下研究：1）外向流与X射线谱指数的关系；2）外向流与红外能谱/谱线以及光学窄发射线线比所示踪的恒星形成的关系；3）在部分遮蔽、紫外光变选活动星系核中外向流与恒星光学光谱测量所获得的星族年龄。

星系中心超大质量黑洞与寄主星系的协同演化一直是天体物理中的热点、难点和前沿问题。依据已有的理论模型，黑洞的吸积反馈在协同演化中可能扮演了十分重要的角色，但是在反馈的物理机制、演化等方面都还知之甚少。本项目在前期唯像研究的基础上，进一步基于活动星系核多波段辐射, 克服了超大质量黑洞吸积辐射与寄主星系光度的高反差带来的测量寄主星系的困难，在红移<1的宇宙中，揭示了反馈随寄主星系的协同演化的观测证据。基于本项目，我们还开启了低质量超大质量黑洞的自旋起源的研究，研究成果被美国天文学会评选为亮点成果，受本项目和组委会的共同资助，于2017年4月在意大利Padova召开的“QUASARS: AT ALL COSMIC EPOCHS”国际会议通过大会报告的形式介绍了该研究成果；我们还开启了“变脸”活动星核搜寻和起源这一国际最新热点的研究。项目总计发表相关论文10篇，其中SCI论文9篇，会议文集一篇。资助培养博士研究生一名。