Handling Source Photometry
The Photometry class is potentially the most fundamental of any in the galfind framework when analyzing photometric imaging surveys.
This simple class stores:
1. An Instrument object to keep track of the photometric filters contained in each object, as well as their order.
2. Masked flux (len(instrument),) array to store the raw photometric fluxes as well as which bands are flagged as unreliable (i.e. masked) for the source.
3. Masked flux_errs (len(flux), 2) array storing the lower and upper \(1~\sigma\) flux errors.
4. depths list or dictionary containing the \(5~\sigma\) local depths of the source. Normally given in units of AB magnitudes.
It is worth noting that even though they are labelled flux and flux_errs, these can in principle be input as magnitudes.
The Photometry class is an abstract base class which is parent to 3 child classes:
- Mock_Photometry: Stores an additional method to scatter the photometric data, and includes a min_pc_err attribute to create photometric errors based on given depths.
- Photometry_obs: Contains an aper_diam attribute storing the aperture size used to generate the photometry as well as a dictionary of SED_result objects, labelled by their respective SED fitting parameters (see [SED fitting](../sed_fitting/sed_fitting.rst) for more details).
- Photometry_rest: Contains a z attribute to store the redshift of the source as well as methods to calculate rest-frame photometric properties (e.g. \(\beta\), \(M_{\mathrm{UV}}\), \(\xi_{\mathrm{ion}}\), line EWs, etc)
In many circumstances it is advantageous to instantiate many Photometry objects at once, for example when reading in a large photometric catalogue. This can be done using the Multiple_Photometry object. Like Photometry, Multiple_Photometry is also an abstract base class which is parent to Multiple_Mock_Photometry and Multiple_Photometry_obs, which contain class methods to load the data in bulk. We do not require a Multiple_Photometry_rest class since it is not common to store rest frame fluxes in photometric catalogues.
Note
Photometry documentation not complete!