Assigned ID: 300 ----- Submission 1 (Fri Jan 21 19:12:06 GMT 2005) ----- A great effort has gone into obtaining extensive time-series spectra of AGN emission and absorption lines with HST. This has shown that the gas is photoionized and distributed over a wide range of density and ionization. The BAL outflows are a case where a wind lies along our line of sight, producing absorption lines, while emission lines are at least partly an outflow above an accretion disk. Analysis of the lines reveals the chemical composition, energetics, and acceleration of the ejected material, and offers clues to the physics of the central powerhouse. HST has allowed these phenomena to be studied in great detail. HST spectra are often analyzed by reference to large-scale plasma simulations that take into account the detailed microphysics of the gas. However, the fact that the continuum source is variable changes some of the assumptions that are the basis of current plasma codes – in particular the assumption that the gas is in a local steady state. Actually, changes in the continuum, and the presence of the flow itself, introduces additional terms into all the rate equations. These can affect the thermal and ionization balance of the gas, and high velocities affects the line and continuum transfer. This proposal requests support for the continued enhancement of the spectral simulation code Cloudy to allow it to do time-dependent calculations. Time-dependent terms will introduce a density-dependent lag in the response of the gas to changes in the continuum, allowing new insights be be gained into the gas conditions. Cloudy is openly available on the web and other investigators use it to produce more than 100 papers per year. This insures that this work will have broad application. I will also create grids of predictions that span the range of parameters seen in AGN, but which include the effects of the outflow on both the physical state of the gas and its resulting spectrum.

AGN/QUASARS 12 58208 One year of postdoc effort. false 0.0 false false false true false SUPPORTED