This is a collaborative research project with William F. Welsh at San Diego State University (AST0086692). 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).
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