MOPEX User's Guide - IRSA

MOPEX User’s Guide
Tile BCD file (coadd_tile_bcd.txt): This text file lists the input images which contribute to
each output tile. The format of the file is the tile ID, the number of contributing images, and
the image index within the stack.
Tile table (coadd_tiles.tbl): A table listing the tiles, their sizes, and their offsets in the x- and
y-directions with respect to the FIF.
Tile uncertainty list (coadd_Tile_*_Unc.fits): The stack of tiled uncertainty images.
Mosaic uncertainty file (coadd_Tile_*_Std_Unc.fits): The stack of tiled standard deviation
images.
DISCUSSION
If the APEX pipeline is appended to a Mosaic pipeline, and you intend to use the mosaic.fits
file from Mosaic as input into APEX, this module should be omitted from the flow. Note that
you must have checked the Keep coadded Tiles box in the Mosaic CoAdder module in the
Mosaic pipeline.
The co-addition can be performed on Tiles (see §8.1), to address computer memory
considerations. The Mosaic CoAdder module performs the co-addition on the individual tiles,
and the Mosaic Combine module then combines the tiles into a single mosaic. Even if only a
single tile is used, Mosaic Combine still needs to be run, in order to produce the expected
products.
There are only two weighting schemes available in the APEX version of this module. The
interpolated images can be combined using the straight averaging or they can be weighted by
exposure time. The co-added uncertainty image is computed, as long as the uncertainty
images are given as an input to the program.
Straight Average: (default) If none of the weighting alternatives are selected, then the coadded
pixel value O is given by the following expression:
O =
∑
j
c jI j
Point Source Extraction (APEX) 123
APEX Modules
C
Equation 6.3