Cold gas and dust in cool-core galaxy clusters

Grants and Contracts Details


Starburst galaxies and Active Galactic Nuclei are among the most luminous objects in the universe, and so can be seen over a broad range of distance and lookback time. The observed spectrum reveals the chemical composition, mass, and luminosity of the central source, allowing their use as a tracer of early galactic evolution. Frequently the sources are hidden behind a veil of obscuring dust, and only hard X-rays, infrared, and radio radiation can be observed. The emitting region is often the outer layer of a molecular cloud that is heated and ionized by an energetic continuum produced by either by a star cluster or massive black hole. A photoevaporative flow is established with an H II region, PDR, 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. The energy source is likely to be variable and conditions and the surrounding gas may not have become time steady so time-dependent conditions must be considered. This project represents a holistic approach to understanding the message contained in the X-ray through radio spectrum. The conditions in absorbing or emitting gas are set by a large number of microphysical processes. We are expanding the plasma simulation code Cloudy to do the spectral formation problems associated with dynamical or time dependent conditions on the coherent and self-consistent basis. The spectral properties of molecular, atomic, and ionized gas and its associated dust will be considered on a self-consistent basis. The properties of the gas and dust are set by interactions between gas, grains, and the radiation field, and the emission is set by a coupled radiative transfer problem. With our previous ATP award we expanded Cloudy to include weak-D and weak-R ionization fronts througb molecule, atomic, and ionized regions, and the code has long been able to do hypersonic flows in ionized gas. We are expanding the simulation to include the effects of advection on the chemistry, and follow time dependent conditions, divergent strong-D and strong-R ionization fronts, and compute shock spectra. Cloudy is openly available and used to produce over 100 papers per year, insuring that the results produced by this proposal will have broad application. The advances proposed here will make the calculations an even truer simulation of what happens in nature. This project falls under Strategic Sub-goal 3D, to discover the origin, structure, evolution and destiny of the universe, and search for Earth-like planets. It supports all NASA missions that do spectroscopy, including Chandra, XMM, FUSE, HST, Spitzer, SOFIA, Webb, and Hersche
Effective start/end date3/15/083/14/11


  • National Aeronautics and Space Administration: $363,867.00


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