Difference between revisions of "The RIMO"

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== Map-level parameter data ==
 
== Map-level parameter data ==
 +
----------------------------
  
 
The map-level data table contains the effective beam solid angle (total and out to different multiples of the beamFWHM) and noise information as follows:
 
The map-level data table contains the effective beam solid angle (total and out to different multiples of the beamFWHM) and noise information as follows:
Line 61: Line 62:
  
 
== Effective band transmission profiles ==
 
== Effective band transmission profiles ==
 +
--------------------------------------
  
 
The effective filter bandpasses are given in different BINTABLE extensions.  The extension is named ''BANDPASS_{name}'', where ''name'' specified the frequency channel.  In the case of the maps, the bandpasses are a weighted average of the bandpasses of the detectors that are used to build the map.  For details see <cite>#planck2013-p03d</cite>.  The bandpasses are given as 4-column tables containing:
 
The effective filter bandpasses are given in different BINTABLE extensions.  The extension is named ''BANDPASS_{name}'', where ''name'' specified the frequency channel.  In the case of the maps, the bandpasses are a weighted average of the bandpasses of the detectors that are used to build the map.  For details see <cite>#planck2013-p03d</cite>.  The bandpasses are given as 4-column tables containing:
Line 81: Line 83:
  
 
The keyword ''F_NYQ'' gives the Nyquist frequency, and can be used together with the number of points in the spectrum to reconstruct the frequency scale. The BINTABLE has the following structure:
 
The keyword ''F_NYQ'' gives the Nyquist frequency, and can be used together with the number of points in the spectrum to reconstruct the frequency scale. The BINTABLE has the following structure:
 
+
-->
  
 
== Beam Window Functions ==
 
== Beam Window Functions ==
 +
---------------------------
  
 
Beam window functions and associated error descriptions are written into a BINTABLE for each ''detection unit'', where ''detection unit'' consists of an auto or a cross product of one or two frequency maps or detset maps used in the likelihood.  Here they are:  
 
Beam window functions and associated error descriptions are written into a BINTABLE for each ''detection unit'', where ''detection unit'' consists of an auto or a cross product of one or two frequency maps or detset maps used in the likelihood.  Here they are:  
Line 97: Line 100:
 
** 857-1,  857-2,  857-3, 857-4
 
** 857-1,  857-2,  857-3, 857-4
  
and the extension names are of the form  
+
and the extension names are of the form ''BEAM_WF_U1XU2''
  
BEAM_''U1''X''U2''
+
where U1 and U2 are one (possibly the same) detection unit from the list above. Each extension contains the columns:
 
+
* ''NOMINAL'' (Real*4) with the window function proper,
where U1 and U2 are one (possibly the same) detection unit from the list above.
+
* ''EIGEN_n'' (Real*4, n=1-5), with the error modes.
 +
and the following keywords
 +
* ''NUMVECT'' (Integer) specified the number of eigenmode vectors, and
 +
* ''LMIN'' and ''LMAX'' (Integer) which give the length of nominal vector
 +
* ''LMIN_EM'' and ''LMAX_EM'' (Integer) that give the range of the valid samples of the eigenmode vectors. Here ''LMAX_EM'' is always less than or equal to ''LMAX'', and the values between ''LMAX_EM''+1 and LMAX is set to NaN
  
  
 +
== Beam Correlation Matrix ==
 +
---------------------------
  
 +
Two of these matrices are given, in two ''IMAGE'' extensions
 +
* CORREL_FREQ, for the frequency channels (21 units),
 +
* CORREL_DETS  for the detsets (351 units).
 +
Each is a symmetric matrix with 1-valued diagonal, made of NBEAMS*NBEAMS blocks, each block being NMODES*NMODES in size.  Each row- (and column-) block entry relates to the B(l) model whose name is indicated in ROW_U1XU2 keywords, and the corresponding eigenmodes are stored in a HDU of the same name. 
  
Each extension contains:
 
* a ''NOMINAL'' column (Real*4) with the window function proper,
 
* five ''EIGEN_n'' columns (Real*4), of error modes.
 
* a keyword ''NUMVECT'' (Integer) specified the number of eigenmode vectors, and
 
* keywords ''LMIN'' and ''LMAX'' which give the length of nominal vector
 
* keywords ''LMIN_EM'' and ''LMAX_EM'' that give the range of the valid samples of the eigenmode vectors. Here ''LMAX_EM'' is always less than or equal to ''LMAX'', and the values between ''LMAX_EM''+1 and LMAX is set to NaN
 
  
  
An example of the FITS header is <span style="color:red">(Preliminary - to be updated)</span>:
 
 
;-----------------------------------------------------------------------------
 
; EXTENSION 11: BEAM_143_DS1X143_5
 
;-----------------------------------------------------------------------------
 
XTENSION= 'BINTABLE'          / binary table extension                         
 
BITPIX  =                    8 / array data type                               
 
NAXIS  =                    2 / number of array dimensions                   
 
NAXIS1  =                  24 / length of dimension 1                         
 
NAXIS2  =                4001 / length of dimension 2                         
 
PCOUNT  =                    0 / number of group parameters                   
 
GCOUNT  =                    1 / number of groups                             
 
TFIELDS =                    6 / number of table fields                       
 
TTYPE1  = 'NOMINAL '                                                           
 
TFORM1  = 'E      '                                                           
 
TTYPE2  = 'EIGEN_0 '                                                           
 
TFORM2  = 'E      '                                                           
 
TTYPE3  = 'EIGEN_1 '                                                           
 
TFORM3  = 'E      '                                                           
 
TTYPE4  = 'EIGEN_2 '                                                           
 
TFORM4  = 'E      '                                                           
 
TTYPE5  = 'EIGEN_3 '                                                           
 
TFORM5  = 'E      '                                                           
 
TTYPE6  = 'EIGEN_4 '                                                           
 
TFORM6  = 'E      '                                                           
 
EXTNAME = 'BEAM_143_DS1X143_5' / extension name                               
 
NUMVECT =                    5 / Number of eigenvectors                       
 
END
 
 
 
== Beam Correlation Matrix ==
 
  
Two of these matrices are given, one for the frequency channels (21x21) and one for the detsets (351x351). Each is a symmetric matrix with 1-valued diagonal, made of NBEAMS*NBEAMS blocks, each block being NMODES*NMODES in size.  Each row- (and column-) block entry relates to the B(l) model whose name is indicated in ROW* keywords below, and the corresponding eigenmodes are stored in a HDU of the same name. 
 
  
The header is of the form <span style="color:red">(Preliminary - to be updated)</span>::
 
  
;-----------------------------------------------------------------------------
 
; EXTENSION 381: CORRBEAM_DET
 
;-----------------------------------------------------------------------------
 
XTENSION= 'IMAGE  '          /                                               
 
EXTNAME = 'CORRBEAM_DET'      /                                               
 
BITPIX  =                  -32 / IEEE single precision floating point         
 
NAXIS  =                    2 /                                               
 
NAXIS1  =                1755 /                                               
 
NAXIS2  =                1755 /                                               
 
DATE    = '2012-11-23'        / Creation date (CCYY-MM-DD) of FITS header     
 
  …
 
NDETS  =                  26 / number of detector assemblies                 
 
NBEAMS  =                  351 / number of beams = NDETS*(NDETS+1)/2           
 
NMODES  =                    5 / number of eigen modes for each beam B(l)     
 
DATAMIN =            -0.979880 / minimum value (should be >=-1)               
 
DATAMAX =              1.00000 / maximum value (should be 1)                   
 
ROW1    = 'BEAM_100-DS1x100-DS1' / block #1 on row (or column)                 
 
ROW2    = 'BEAM_100-DS1x100-DS2' / block #2 on row (or column)                 
 
ROW3    = 'BEAM_100-DS1x143-DS1' / block #3 on row (or column)                 
 
...
 
ROW350  = 'BEAM_857-3x857-4'  / block #350 on row (or column)                 
 
ROW351  = 'BEAM_857-4x857-4'  / block #351 on row (or column)                 
 
END
 
 
[[CAtegory:Mission science products|003]]
 
[[CAtegory:Mission science products|003]]

Revision as of 12:03, 6 March 2013

Overview[edit]

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. It is described in detail in The HFI and LFI RIMO ICD (ref). 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 scalars to give properties such as a noise level or a representative beam FWHM
Table 
to give, e.g., filter transmission profiles or noise power spectra
Map 
namely 2-D "flat" maps, to give, e.g., the main beam shape

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



Map-level parameter data[edit]


The map-level data table contains the effective beam solid angle (total and out to different multiples of the beamFWHM) and noise information as follows:

FREQUENCY 
a 3-digit string giving the reference frequency in GHz, i.e., of the form 044 or 217
Omega_total
total beam solid angle in armin^2
Omega_1fwhm 
beam solid angle out to 1FWHM in arcmin^2
Omega_2fwhm 
beam solid angle out to 2FWHM in arcmin^2
FWHM_eff 
FWHM of a Gaussian beam having the same (total) solid angle, in sr. This is the best value for source flux determination
FWHM_gauss 
FWHM derived from best Gaussian fit to beam maps, in sr. This is the best value for source identification
NOISE 
This is the typical noise/valid observation sample as derived from an appropriate combination of the NETs of the valid detectors used in the map.

For the Omega columns, the 'DISP' (for dispersion) column gives an estimate of the spatial variation as a function of position on the sky. This is the variation induced by combining the scanning beam determined from the planet observations with the scanning strategy, as described in Detectors pointing & beam.

The BINTABLE extension has the following structure


Effective band transmission profiles[edit]


The effective filter bandpasses are given in different BINTABLE extensions. The extension is named BANDPASS_{name}, where name specified the frequency channel. In the case of the maps, the bandpasses are a weighted average of the bandpasses of the detectors that are used to build the map. For details see #planck2013-p03d. The bandpasses are given as 4-column tables containing:

WAVENUMBER 
the wavenumber in cm-1, conversion to GHz is accomplished by multiplying by [math]10^{-7}c[/math] [mks].
TRANSMISSION 
the transmission (normalized to 1 at the max for HFI and to have an integral of 1 for LFI)
ERROR 
the statistical [math]1-\sigma[/math] uncertainty for the transmission profile (not provided for LFI).
FLAG 
a flag indicating if the data point is an independent frequency data point (nominally the case), or an FTS instrument line shape (ILS)-interpolated data point. The frequency data has been over-sampled by a factor of ~10 to assist in CO component separation efforts #planck2013-p03a, #planck2013-p03d.

The number of rows will differ among the different extensions, but are the same, by construction, within each extension.


Beam Window Functions[edit]


Beam window functions and associated error descriptions are written into a BINTABLE for each detection unit, where detection unit consists of an auto or a cross product of one or two frequency maps or detset maps used in the likelihood. Here they are:

  • the 6 HFI frequency channels, producing 21 extensions
    • 100, 143, 217, 353, 545, 857
  • 26 detsets, producing 351 extensions; the detsets used are, by frequency channel:
    • 100-DS1, 100-DS2,
    • 143-DS1, 143-DS2, 143-5, 143-6, 143-7,
    • 217-DS1, 217-DS2, 217-1, 217-2, 217-3, 217-4,
    • 353-DS1, 353-DS2, 353-1, 353-2, 353-7, 353-8,
    • 545-1, 545-2, 545-4,
    • 857-1, 857-2, 857-3, 857-4

and the extension names are of the form BEAM_WF_U1XU2

where U1 and U2 are one (possibly the same) detection unit from the list above. Each extension contains the columns:

  • NOMINAL (Real*4) with the window function proper,
  • EIGEN_n (Real*4, n=1-5), with the error modes.

and the following keywords

  • NUMVECT (Integer) specified the number of eigenmode vectors, and
  • LMIN and LMAX (Integer) which give the length of nominal vector
  • LMIN_EM and LMAX_EM (Integer) that give the range of the valid samples of the eigenmode vectors. Here LMAX_EM is always less than or equal to LMAX, and the values between LMAX_EM+1 and LMAX is set to NaN


Beam Correlation Matrix[edit]


Two of these matrices are given, in two IMAGE extensions

  • CORREL_FREQ, for the frequency channels (21 units),
  • CORREL_DETS for the detsets (351 units).

Each is a symmetric matrix with 1-valued diagonal, made of NBEAMS*NBEAMS blocks, each block being NMODES*NMODES in size. Each row- (and column-) block entry relates to the B(l) model whose name is indicated in ROW_U1XU2 keywords, and the corresponding eigenmodes are stored in a HDU of the same name.

reduced IMO

Flexible Image Transfer Specification

(Planck) High Frequency Instrument

(Planck) Low Frequency Instrument

Interface Control Document

Full-Width-at-Half-Maximum

Instrument Line Shape