The RIMO

Overview

The RIMO, or Reduced Instrument Model is a FITS file containing selected instrument characteristics that are needed by users who work with the released data products. There will be two RIMOs, one for each instrument, which will follow the same overall structure, but will differ in the details. The type of data in the RIMO can be:

Parameter 

namely scalers to give properties such as a noise level or a representative beam FWHM

Table 

to give filter transmission profiles or noise power spectra

Map 

to give beam shape

The different types of data are written into different BINTABLE extensions of the FITS file, and these are described below.

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Outstanding business:

• common or mixed items, like, eventually cross beam window functions between an HFI and an LFI beam

Detector-level parameter data

There are no detector-level products in the first release, so there will be no detector-level parameters in the accompanying RIMO. This section will serve for later releases.

The detector parameter data are given in the form of a table giving the parameter values for each detector. The table columns are (with the column names in parentheses):

DETECTOR

these are the detector names. For HFI these will be of the form 217-3 for SWBs or 100-3b for PSBs, and for LFI they will have the form 27M or 18S. There are 52 HFI detectors and 22 LFI detectors.

PHI_UV, THETA_UV, and PSI_UV 

The angles that give the rotation of the beam pattern from a fiducial orientation (forward beam direction (z-axis) pointing along the telescope line of sight, with y-axis aligned with the nominal scan direction) to their positions in the focal plane. All angles are in radians

PSI_POL 

is the direction of maximum polarization, defined with the beam in the fiducial orientation described above, that is, before rotation onto the detector position.

EPSILON 

the cross-polarization contamination (or leackage).

FWHM 

the mean FWHM of the beam (arcmin TBC).

ELLIPTICITY 

the beam ellipticity (no units)

POSANG 

the position angle of the beam major axis