Simulated Observations: Request for Corrections
Hi all, I've been taking stock of where we are for simulated observations, and I wanted to run this past everyone to make sure I'm not missing anything. I think we have four mechanisms for generating something that could *generously* be called a "Simulated Observation," but for each approach there are caveats. If someone has something to add, in terms of capability or caveats, I would be eager to hear. I have not included any methods for generating spectra from galaxies, but I believe this may have been done using the second method below. = X-ray Observations = Under the assumption of optically thin gas, projections can be made using emissivity to generated simulated observations. yt includes a method for handling output from CLOUDY in the ROCO (Smith et al 2008) format, and generating integrated emissivity over given energy ranges. Caveats: The ROCO format for input requires some non-trivial handling of CLOUDY output. = SED Generation and Deposition = Using BC03 models for stellar population synthesis, star particles in a given calculation can be assigned an integrated flux for a specific bandpass. These fluxes can then be combined using either projections or volume rendering. This can use CIC interpolation to deposit a total flux into each cell (which should be flux-conserving, modulo a multiplicative factor not currently included) which is then either projected or volume rendered. Caveats: The deposition method produces far too washed out and murky results. The multiplicative factor is not currently set correctly universally. = Thermal Gas Emission = Applying a black body spectrum to the thermal content of the gas, we can volume render the domain and apply absorption based on broad arguments of scattering. One could theoretically include star particles as point sources in this, using recent changes to the volume renderer. Caveats: Scattering that results in re-emission is completely neglected, such as Halpha emission. Scattering that results in just attenuating the emission is set in an ad hoc fashion. Emission from point sources, if included at all, is included in a non-conservative fashion. = Export to Sunrise = Data can be exported to Sunrise for simulated observation generation. Caveats: This process is poorly documented. Does that all sound about right? Does anybody have any additions or corrections to this? Thanks, Matt
participants (5)
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Britton Smith
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Eric Hallman
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j s oishi
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John Wise
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Matthew Turk