In order to carry out point source extraction, MOPEX will expect some or all of the following files as input. See the sections on Input for more information on the format of these files.
· A text file containing a list of input data images or a single input image (e.g. Spitzer BCD frames; required)
· A text file containing a list of input uncertainty images or a single uncertainty image (optional)
· A text file containing a list of input status masks images or a single mask image (optional)
· A PRF image file or PRF map (e.g. PRF.fits; required)
· A permanently damaged pixel mask image (pmask; optional)
· A "namelist" file specifying the parameters to be used for mosaicking (Command-Line MOPEX only; required)
· A user-defined source list file (User List mode only), defining the positions of the sources to be extracted. See §8.10 for more information.
6.3 Running APEX
To load a standalone APEX pipeline (i.e. without appending to an existing Mosaic pipeline), either start from a MOPEX template namelist (e.g. File > New APEX multiframe Pipeline), load an existing APEX namelist file (File > Read Name List) or load an empty flow and insert an APEX pipeline from there (File > New Empty MOPEX Pipeline, then go to e.g. Insert APEX single frame at the top of the flow window and choose Empty Pipeline). If you choose the last option, MOPEX will load an empty APEX flow to which you can add and subtract modules, and modify the input parameters.
Many users will wish to append an APEX pipeline to the end of a Mosaic pipeline to use the previously-generated mosaic file as input. We generally encourage this, as the mosaicking within APEX does not carry out outlier rejection. To do this, click on the e.g. Insert APEX User List multiframe rectangular button at the top of the Overlap window. This will pull up a dialogue box giving you three options. Choose From File to load a previously-created namelist from file, From Template to start from one of the inbuilt APEX templates, and Empty Pipeline to open an empty APEX flow that you can build up by hand. If you have previously added and deleted an APEX pipeline from a particular flow, the last option will instead read Re-add Pipeline.
For information on running APEX on the command line, see Chapter 9.
6.3.1 Using a Previously-Generated Mosaic with APEX
As mentioned above, creating the mosaic for source detection within the APEX Multiframe pipeline has a major disadvantage in that it doesn’t perform any outlier rejection, often leading to the detection of a number of spurious sources. We recommend creating the mosaic file using the Mosaic pipeline, and then using this as input into the APEX Multiframe flow. Do this by running the Mosaic pipeline with the Keep coadded Tiles option checked in the Mosaic CoAdder module, then appending the APEX Multiframe pipeline onto the end of the Mosaic flow. Remove the Fiducial Image Frame, Mosaic CoAdder and Mosaic Combine modules from the APEX pipeline and run it through to the end. APEX will automatically take the mosaic file from the Mosaic pipeline as input.
