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HR Sparse-mode Feature Finder product table information

For each partially or fully extended source observed in HR sparse mode there are two
sets of FF results; one for the point-source calibrated spectra and one for the extended-
source calibrated spectra

The "Flag" column indicates semi-extended targets and extended targets with S-EXT
and EXT. Whether a highly processed data product was used is indicated with the HPDP
flag. You can visit the Spectrometer calibrators legacy data page or click on a HPDP
flag in the table to find the HPDP used. A BGS flag indicates background corrected
data was used, where the mean of the spectra from several smoothed off-axis detectors
was subtracted (following Hopwood et al. 2015; arXiv:1502.05717). You can visit the
Background subtracted data page or click on a BGS flag in the table to find the BGS
data used.

Source that are assigned the S-EXT or EXT flags, may see issues with their Feature
Finder results, as the point-source calibration scheme is optimal for point-like sources
and extended-source calibration optimal for fully extended sources. The postcard pairs
for these observations provide a quick way to compare the calibration schemes applied
for sparse-mode (single-pointed) FTS products associated to sources with some
spatial extent. If a source had an intrinsic size much larger than the beam (≫ 42′′), the
FF results for point-source calibrated data may show issues, such as fringing found as
features or a poor fit to the continuum. For partially extended sources, there may be
weaker features in the SSW spectrum, while high fringing may still be present in the SLW
spectrum.

For sources with spatial extent, the extended-source calibrated products are provided as
an alternative, as these may offer improved results for one or both of the centre detectors
(SLWC3 and SSWD4). The extended-source calibrated FF results may also be better for
some sources that are not fully extended, but do have significant extent within the FTS
beam. Therefore all sources that have been classed as semi-extended (by assessing any
discontinuity between the bands and, where available, associated PACS photometer maps)
are included. However, if a source is not significantly extended, the extended-source
calibrated FF results may not improve upon the point-source calibrated ones. The point-
and extended-source calibrated FF results have been visually compared for all the sources
assigned a semi/fully extended classification. If the extended-source calibrated results were
found to improve upon the respective point-source results, that is indicated in the "flag"
column with an asterisk (e.g. EXT*) and for which detectors (SLWC3/SSWD4). Improvements
include extra features found, fewer spurious features or an improved fit to the continuum.
It may be that neither calibration scheme produces a satisfactory FF results, or the
results are the same.

Back to products for HR sparse observations [p.1, p.2, p.3, p.4, p.5 ]

-- Rosalind Hopwood - 2017-03-15

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Topic revision: r2 - 2017-03-15 - RosalindHopwood
 
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