Unraveling the Message of the Light - Spectral Diagnostics of AGN and Starbursts

Grants and Contracts Details


Starburst galaxies and Active Galactic Nuclei are among the most luminous objects in the universe, nd so can be seen over a broad range of distance and lookback time. The observed spectrum Ireveals the chemical composition, mass, and luminosity of the central source, allowing their use as a racer of early galactic evolution. Frequently the sources are hidden behind a veil of obscuring dust, nd only hard X-rays, infrared, and radio radiation can be observed. The emitting region is often the uter layer of a molecular cloud that is heated and ionized by an energetic continuum produced ither by a star cluster or massive black hole. A photoevaporative now is established with an H II region, POR, and molecular core forming successive layers. A vast number of ionic, atomic, and molecular emission lines, together with a thermal dust continuum, are emitted, and can be used to understand conditions within the source. 'his project represents a holistic approach to understanding the message contarned in the spectrum. 'he emitting regions are in a non-equilibrium state - the physical conditions are set by a large I number of microphysical processes. We are expanding the plasma simulation code Cloudy to do the spectral formation problems associated with such sources on the coherent and self-consistent basis, Magnetohydrodynamics provides the physical link between the now from molecular to ionized Iregions. The gas and dust emission is set by the interactions between grains, the gas, and the lincident radiation field, and the entire spectral radiative transfer problem must be solved. With our previous ATP award we expanded the simulations to include weak-D and weak-R ionization fronts, predicted the emission from size-resolved grain populations, included a full chemistry network, and improved predictions of molecular, atomic, and ionic emission. Here we propose expanding the physics to do divergent strong-D and strong-R fronts, time dependence, shocks, and improve the rain molecular physics. Cloudy IS openly available and used to produce roughly 100 papers per ear, insuring that the results produced by this proposal will have broad application.
Effective start/end date3/15/053/14/08


  • Goddard Space Flight Center: $236,514.00


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