VII. 3-Band Cryo Data Release
3. 3-Band Cryo Data Processing
Science data processing for the WISE 3-Band Cryo survey phase
was carried out using version 4.5 of the WISE Science
Data System (WSDS). WSDS v4.5 was adapted from WSDS v4 which was
used to process the full cryogenic survey data, and that produced
the All-Sky Release data products. WSDS v4.5 maintains all of the
major elements of the earlier version, and preserves all improvements and
benefits that constitute WISE second-pass
The modifications that were made for WSDS v4.5 deal primarily with dropping
W4 data from all aspects of the processing, and accommodating the changes
to and time-dependence of the performance of the W1, W2 and W3 detectors.
During the full cryogenic mission phase, the WISE payload was so
stable that a single set of calibration image products and parameters could
be used for the entire data set. 3-Band Cryo phase processing required
developing the infrastructure for time-dependent calibrations and
algorithms in many of the pipeline science modules.
Section VII.3.a contains a summary
of the major pipeline changes that were made for 3-Band Cryo data processing.
The basic design, functionality and algorithms for each WSDS pipeline
science module are described in IV.4.
Changes to the individual modules for WSDS v4.5 are described in more detail
in sections VII.3.b-i. Modules that are not explicitly included
within subsections in VII.3 are largely unchanged from WSDS v4.
a. Summary of Pipeline Modifications for 3-Band Cryo Processing
- Functionality that involves W4 data was removed from all
science modules and pipeline wrappers.
- Infrastructure for handling time-dependent parameter file input
for all science modules was introduced. This was generally handled
by defining discrete calibration intervals during which calibration
products and module parameters are fixed. Different modules
utilized different intervals.
- Operating parameters for all modules were tuned for the
characteristics of 3-Band Cryo data.
- New and time-dependent calibrations were developed and utilized
in the Single-Exposure Image Calibration (VII.3.b),
Position Reconstruction (VII.3.d), and
Photometric Calibration (VII.3.g).
- Saturated pixel tagging was
was recovered for bright point sources using prior knowledge of
the position and flux from the All-Sky Catalog and external sources
- Parameters used to compute of the probability of flux variability
were updated, and the computation in W3 was dropped because
of the severe changes in sensitivity in that
band during the 3-Band Cryo operations
- The Source Working Database that contains the deep source extractions
from Multiframe Pipeline processing
was not split into a separate Catalog and Reject Table in the
Final Product Generation step.
- Positional associations with All-Sky Release Catalog sources
were added to the 3-Band Cryo Source Working Database
Last Update: 2012 July 26