IRAC Instrument Handbook - IRSA - California Institute of Technology

Pipeline History Log 141
IRAC Instrument Handbook
The pipeline darkdrift module reduces a "jailbar" bias effect in the IRAC images. The values used for the
reduction within the pipeline are included in the header of the full array data, and now in the header of the
subarray data for all the planes. This allows the user to remove the correction, if desired.
6. Mosaic Header Updated
We have added more information to the mosaic header. These changes are explained in the IRAC
Instrument Handbook, Section 6.
S16.0
1. Labdark Change for 100 Second HDR Data
Within 100s AORs, the channel 4 observations are split into two 50s frames. The second 50s frame
received an incorrect non-HDR 50s labdark instead of an HDR labdark. This was a minor problem, and
has now been corrected.
2. Muxbleed Correction Updated
The module that detects and corrects the muxbleed caused by bright sources has been updated. It now
performs a more consistent and better correction than previously.
3. Artifacts Flagged Within the Pipeline
The imasks (*_bimsk.fits) now include masking for muxbleed, column pulldown and banding induced by
bright sources on images. The updated masks can be used with existing contributed software to mitigate
bright source artifacts, and will be used in future versions of the IRAC pipeline after mitigation
algorithms have been implemented. In general, observers should not flag artifacts in mosaicking unless
they have observations at various roll angles.
4. Pixel Linearization
The handling of bad and saturated pixels has been changed - they are in most cases now left with their
original values, as opposed to being set equal to NaN. The method of flagging saturation in BCD mask
files was changed, and now more accurately reflects the presence of saturation.
S15.0
1. Ghost Images And Scattered Light Flagged Within Pipeline
Pipeline versions of the ghost image and scattered light detection algorithms have been integrated into the
IRAC pipeline. The modules use the location of bright sources upon the array (ghost image) or just
outside the array, as found in 2MASS catalogs (scattered light) to predict possible optical ghosts and
scattered light locations, and flag these pixels within the imask. The imask is an ancillary data product
now available through the archive. IRAC observers should use the imask instead of the dmask when
making mosaics etc.
2. Incorrect Group Ids in Header to Be Fixed
A bug that caused a small percentage of BCDs (< 0.1%) to have an unreadable header and which were
therefore not pipeline-processed, has been fixed. This should significantly decrease the number of missed
BCDs in large mapping programs.
S14.0