IRAC Instrument Handbook - IRSA - California Institute of Technology

S18.0
Pipeline History Log 140
IRAC Instrument Handbook
1. Muxbleed Correction Update
The correction of the muxbleed effect in the BCD frames was updated. After extensive testing a new
functional form and scaling law was developed for muxbleed correction in channels 1 and 2. The new
functional form and scaling law correct muxbleed better than before.
2. MOPEX Now Using the bimsk.fits Files
In creating the final mosaic image, *maic.fits, the MOPEX pipeline now uses the *bimsk.fits files as
input, instead of the *dmsk.fits files. The *bimsk.fits files have more relevant information useful for
flagging when building mosaics and analyzing the images.
3. Header Information Updated
WCS CD matrix keywords were added to the Post-BCD file headers. The CDELT1, CDELT2, and
CROTA2 keywords have been preserved but were placed in comments to avoid any confusion when
handled by astronomical software. The following keywords were added to the BCD, CBCD, and Post-
BCD image files: PXSCAL1, and PXSCAL2, and PA. The keywords are the pixel scale along axis 1 and
axis 2 in arcsec/pixel and the position angle of axis 2 (East of North) in degrees. Keywords containing
additional information on the AOR mapping parameters have been added in a separate section of the
header.
S17.0
1. Artifact Mitigation Within the Pipeline
Artifact-mitigated images from the BCD pipeline and their associated uncertainty images (*cbcd.fits and
*cbunc.fits) are now available in the archive. These images include corrections for column pulldown and
banding, induced by bright sources in the images. The corrections are empirical fits to the BCDs and may
not always improve the data quality. The standard BCD files (*bcd.fits) remain available in the archive.
The mosaics (post-BCD products) are now created from the *cbcd.fits images.
2. Muxbleed Correction Updated Again
The muxbleed correction has been revised to include a better empirical fit.
3. Two-Dimensional Subarray Images
A two-dimensional image is now generated for each subarray BCD cube. Each pixel in the 2D image
(*sub2d.fits) is a robust (outlier-rejected) mean of the 64 samples of the *bcd.fits cube. Two-dimensional
masks, uncertainty images, and coverage maps are now also provided.
4. Artifacts Now Flagged For Subarray Images
The subarray imasks (*_bimsk.fits) now include masking for muxbleed, column pulldown and banding,
induced by bright sources. The updated masks can be used to mitigate bright source artifacts the same
way as with the full array data.
5. Darkdrift Values Written Out in the Subarray Header