Collaborative Research: The HET Echo Mapping Project

AST-0086692William F. welsh与德克萨斯大学奥斯汀分校的Edward L. Robinson合作研究项目（AST0086683）。本项目将利用9米霍比-埃伯利望远镜（HET）获取QSO宽线区域的高信噪比光谱，并进行良好的时间采样，分析全运动光谱轮廓随时间的变化。这些将用于测试宽线发射区域的不同运动学QSO模型（流入与流出）。潜伏在许多大质量星系中心的是超大质量黑洞（BH）。如果附近有物质，黑洞会捕获并吸积这些物质，释放出大量的能量，这将以星系核亮度增加的形式出现。拥有这种吸积黑洞的星系被称为有一个“活动核”（AGN）。吸积本身就是一个不稳定的过程。靠近黑洞的吸积区被称为宽线区（BLR）。BLR是发光的，因为它被非常接近黑洞产生的硬（紫外线和x射线）连续通量光电离。因为电离辐射是可变的，所以BLR也是。因此，BLR的发射线“回应”了连续通量的变化。利用这些“回声”结构在黑洞附近以微弧秒的尺度进行映射。要做到这一点，我们需要一个很长时间的基线，对BLR的变化进行充分抽样观察。这需要数周或数月的数据。“HET回声测绘项目”是一项新的研究项目，其目的是：(1)绘制BLR气体的大小、几何形状和流量。(2)利用BLR的几何和运动学直接估计黑洞中心的质量。(3)用质量是先前测量的10到100倍的黑洞来绘制AGN。(4)测量任何吸积风的参数和BLR的时间变化。本项目由美国国家科学基金会星系外天文学和宇宙学项目（AST/EXC）资助

AST-0086692William F. WelshThis is a collaborative research project with Edward L. Robinson at the University of Texas at Austin (AST0086683). This project will use the 9m Hobby-Eberly Telescope (HET) to obtain high signal-to-noise spectra of QSO broad line regions, with good time sampling, to analyze changes in the full kinematic spectral profiles as a function of time. These will be used to test different kinematic QSO models ( inflow vs. outflow) for the broad line emission regions.Lurking at the center of many massive galaxies are supermassive Black Holes (BH). If there is material nearby, the BH will trap and accrete this matter releasing a huge amount of energy which will show up as increased luminosity of the galaxy nucleus. Galaxies which possess such an accreting BH are said to have an "active Nucleus" (AGN). Accretion is an inherently unstable process. The accretion region close to the BH is called the Broad Line Region (BLR). The BLR is luminous because it is photoionized by the hard (UV and x-ray) continuum flux produced very close to the BH. Because this ionizing radiation is variable, so is the BLR. Thus the emission lines from the BLR "echo" the variations in the continuum flux. Using these "echoes" structures near the BH with microarcsecond scales can be mapped. To do this one needs a very long time baseline of well-sampled observations of the variations in the BLR. This requires data over weeks or months. The "HET Echo Mapping Project" is a new research project which aims to: (1) Map the size, geometry, and flow of the BLR gas. (2) Make direct estimates of the mass of the central BH using the geometry and kinematics of the BLR. (3) map AGN with BH of 10 to 100 times the mass of those previously measured. (4) Measure the parameters of any accretion wind and the temporal changes in the BLR. Funding for this project was provided by the NSF program for Extragalactic Astronomy & Cosmology (AST/EXC).***