Collaborative Research: The HET Echo Mapping Project

这是与德克萨斯大学奥斯汀分校的爱德华·L·罗宾逊(Edward L.Robinson)合作的研究项目(AST0086683)。该项目将使用9米Hobby-Eberly望远镜(HET)获得类星体宽线区域的高信噪比光谱，并具有良好的时间采样，以分析完整的运动学光谱剖面随时间的变化。这些将被用来测试不同的运动学类星体模型(流入和流出)，用于宽线发射区。许多大质量星系的中心潜伏着超大质量黑洞(BH)。如果附近有物质，黑洞将捕获并共生这种物质，释放出巨大的能量，这将表现为星系核光度的增加。拥有如此吸积的黑洞的星系被称为“活动核”(AGN)。吸积是一个天生不稳定的过程。靠近BH的吸积区称为宽线区域(BLR)。BLR是发光的，因为它是由非常接近BH产生的硬的(紫外线和X射线)连续通量光致电离的。因为这种电离辐射是可变的，所以BLR也是可变的。因此，来自BLR的发射线“回响”了连续谱通量的变化。利用这些微弧秒尺度的黑洞附近的“回波”结构，就可以绘制出地图。要做到这一点，需要一个很长的时间基线，对BLR的变化进行充分采样的观测。这需要数周或数月的数据。HET回波测绘项目是一项新的研究项目，其目的是：(1)测绘BLR气体的大小、几何形状和流动。(2)利用BLR的几何和运动学信息直接估计中央BH的质量。(3)MAP活动星系核的质量是先前测量的质量的10-100倍。(4)测量任何积积风的参数和BLR的时间变化。该项目的资金由NSF河外天文与宇宙学计划(AST/EXC)提供。*

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).***