File Description:

SPIRE image, error, coverage cubes
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M31-PLWmap_MS-DR2-extended-head.fits - 500 micron maps optimized for extended-source photometry
M31-PLWmap_MS-DR2-point-head.fits    - 500 micron maps optimized for point-source photometry
M31-PMWmap_MS-DR2-extended-head.fits - 350 micron maps optimized for extended-source photometry
M31-PMWmap_MS-DR2-point-head.fits    - 350 micron maps optimized for point-source photometry
M31-PSWmap_MS-DR2-extended-head.fits - 250 micron maps optimized for extended-source photometry
M31-PSWmap_MS-DR2-point-head.fits    - 250 micron maps optimized for point-source photometry

PACS maps
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M31_rev_offst_pacs100_drf.fits       - 100 micron drift map
M31_rev_offst_pacs100_err.fits       - 100 micron error map
M31_rev_offst_pacs100_img.fits       - 100 micron science map
M31_rev_offst_pacs100_wei.fits       - 100 micron weight map
M31_rev_offst_pacs160_drf.fits       - 160 micron drift map
M31_rev_offst_pacs160_err.fits       - 160 micron error map
M31_rev_offst_pacs160_img.fits       - 160 micron science map
M31_rev_offst_pacs160_wei.fits       - 160 micron weight map

For more information, see the following resources:

1. Fritz et al. (2012)
http://adsabs.harvard.edu/abs/2012A%26A...546A..34F

2. Documentation from Data Set Provider
http://irsatest.ipac.caltech.edu/data/Herschel/HELGA/docs/README_HELGA