The target list modules take catalog data from a StarCatalog object and, using additional information and methods from Completeness, OpticalSystem, and ZodiacalLight objects, generate an input target list for a survey simulation. The basic functionality is fully implemented by the TargetList prototype, with other implementations focused on special cases, such as the KnownRVPlanetsTargetList. The end result is an object analogous to the StarCatalog, with target attributes stored in equally sized numpy.ndarrays. Fig. 30 shows the initialization of the TargetList prototype.
After parsing keyword inputs and instantiating objects of StarCatalog, OpticalSystem, PostProcessing, ZodiacalLight, and Completeness, the prototype TargetList initialization calls populate_target_list(), which makes StarCatalog attribute property arrays attributes of the TargetList object, fills in missing photometric data (if the fillPhotometry keyword input is set to True), and assigns each target system additional, computed attributes:
The true and approximate stellar mass (attributes MsEst and MsTrue , respectively), calculated in stellar_mass(). The estimated mass is based on the Mass-Luminosity relationship from [Henry1993] and the ‘true’ mass is equal to the estimated mass of each star plus a randomly generated Gaussian value with mean 0 and standard deviation of 7% (the error associated with the fit in that publication).
The inclination of the target system’s orbital plane (attribute I), calculated in gen_inclinations(). This is used only if the commonSystemInclinations keyword input to the SimulatedUniverse is set to True. The inclinations are sinusoidally distributed, within the bounds set by the PlanetPopulation attribute Irange.
The \(\Delta\textrm{mag}\) and completeness values associated with the integration cutoff time set in the OpticalSystem and the saturation integration time (i.e., the point at which these values stop changing). For optical systems where there is no fundamental noise floor (i.e., where SNR can always be increased with additional integration time) the saturation \(\Delta\textrm{mag}\) is effectively infinite, but the saturation completeness is limited to the maximum obscurational completeness for that system (see [Brown2005] for details). These values, along with the user-selectable \(\Delta\textrm{mag}_\textrm{int}\) and \(WA_\textrm{int}\) are calculated in calc_saturation_and_intCutoff_vals(), which calls helper methods calc_saturation_dMag() and calc_intCutoff_dMag().
The single-visit Completeness (attribute int_comp) based on \(\Delta\textrm{mag}_\textrm{int}\).
Finally, the whole target list is filtered by filter_target_list(), based on filters selected by input keywords. The default filter set removes binary stars (or stars with close companions), systems where obscurational completeness is zero (i.e., all planets are inside the IWA or outside the OWA), and systems for which the integration cutoff completeness is less than the minComp input value.