MULTI-TEMPERATURE COLUMN DENSITY MAPPING OF THE GALACTIC PLANE
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The directory "PPMAP_Results" contains a set of multi-temperature dust column 
density maps, in FITS format, obtained by applying the PPMAP technique to
all 163 tiles of the Hi-GAL survey. These data cover the entire Galactic 
Plane in a strip of approximate width 2 deg in latitude. The PPMAP algorithm 
itself is described by Marsh et al. (2015 MNRAS 454, 4282), and its application 
to the Hi-GAL survey is described by Marsh et al. (2017, submitted to MNRAS).

The results are presented in a set of separate subdirectories, one for each 
tile. Each is labelled by a three-digit integer (NNN) representing the 
approximate Galactic longitude of the tile centre in degrees. The following 
files are present in each case:

lNNN_diffcdens.fits	=	Image cube of differential column density
				as a function of Glon, Glat, & Td, where
				Glon and Glat are Galactic longitude & latitude,
				and Td is dust temperature.

lNNN_sigdiffcdens	=	Corresponding uncertainty cube, representing
				the 1-sigma uncertainty levels

lNNN_cdens.fits		=	2D map of integrated line-of-sight column
				density

lNNN_temp.fits		=	2D map of mean line-of-sight dust temperature


Each file represents a field of view of approximately 2.4 deg square, with
a pixel size of 6 arcsec for the two spatial dimensions. The third axis of 
the image cubes represents a grid of 12 values of dust temperature whose 
values are specified by the TEMPn keywords in the FITS header, where n is
a two-digit integer. The units of differential column density in the image
cubes are 10^20 H2 molecules per cm^2 per temperature interval. For further
details please see Marsh et al. (2015). 

This work was carried out at Cardiff University as part of the EU-funded 
ViaLactea project (Molinari et al. 2010, PASP, 122, 314).