These FITS images were generated with the IDL package MIRphot
[Asmus2014] by extraction (and combination) of the sub-images from the
chopped/nodded total images from COMICS, Michelle, T-ReCS and VISIR (see
[Asmus2014] for details).
The FITS images contain the central ~4 arcsec of each source centered on
the (putative) nuclear position with North being up and East to the
left. The WCS registration has been performed after extraction by using
coordinates of the nucleus from other wavelengths (mostly 2MASS and
NED). The uncertainty of these reference position is usually less than 1
arcsec. In addition, the imprecision of the assignment itself is ~1px ~
0.1".
The FITS images are flux calibrated (unit is mJy) using the Gaussian 2D
fits to the corresponding STD observation (where available, otherwise
using the median conversion factor for the used instrument/filter
settings). Therefore, correction factors have to be applied in case
other flux measurement methods are applied to the images. The flux
values given in the FITS headers should be regarded as approximate
values. In particular for the instruments, VISIR and COMICS, they are
not necessarily exactly equal to the values provided in the photometry
results table, because many flux measurements were performed during the
process of combining individual subimages (all in MIRphot), instead of
in the final combined image, provided here. The used total images are
available upon request. Note, however, that these are just the products
of the observatory-delivered pipelines with default parameters.
.. [Asmus2014] Asmus D., Hoenig S.F., Gandhi P., Smette A.,
Duschl W.: The subarcsecond mid-infrared view of local active
galactic nuclei: I. The N- and Q-band imaging atlas,
2014MNRAS.439.1648A_
