Difference between revisions of "The RIMO"

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 +
{{DISPLAYTITLE:The instrument model}}
 
== Overview ==
 
== 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 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:
−
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
+
; Parameter : namely scalars to give properties such as a noise level or a representative beam FWHM
−
; Table : to give filter transmission profiles or noise power spectra
+
; Table : to give, e.g., filter transmission profiles or noise power spectra
−
; Map : to give beam shape
+
; Image : namely 2-D "flat" array, to give, e.g., the beam correlation matrices
  
−
The different types of data are written into different BINTABLE extensions of the FITS file, and these are described below.
+
The FITS file begins with primary header that contains some keywords that mainly for internal use and no data.  The different types of data are written into different BINTABLE (for parameters and tables) or IMAGE (for 2-D arrays) extensions, as described below.
  
−
-----------
+
=== File Names ===
  
−
<span style="color:red"> Outstanding business:
+
; HFI: {{PLASingleFile|fileType=rimo|name=HFI_RIMO_R1.10.fits|link=HFI_RIMO_R1.10.fits}}
−
* <span style="color:red">common or mixed items, like, eventually cross beam window functions between an HFI and an LFI beam
+
; LFI: {{PLASingleFile|fileType=rimo|name=LFI_RIMO_R1.12.fits|link=LFI_RIMO_R1.12.fits}}
  
−
</span>
 
  
 +
<!--
 +
== Detector-level parameter data ==
  
−
== Detector-level parameter data ==
+
There  are no detector-level products in the first release.
 +
 
 +
 
 +
The detector parameter data are given in the form of a table giving the parameter values for each detector.  The table columns (whose names are in ''BOLD ITALICS'') are:
 +
 
 +
; Bolometer name - ''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.
  
−
<center>
+
; Focal plane geometry parameters - ''PHI_UV'', ''THETA_UV'', and ''PSI_UV'' : These parameters give the geometry of the focal plane, or the positions of the detectors in the focal plane. 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. The fiducial position is that given by the Star Tracker. All angles are in radians. These parameters are derived from observations of bright planets; see [[Detector_pointing | Detector pointing]] for details.
−
{| border="1" cellspacing="0" cellpadding="5" align="center" style="background:silver"  width="600px"
 
−
!
 
−
<span style="color:red"> 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 </span>
 
−
|}
 
−
</center>
 
  
 +
; Polarization parameters - ''PSI_POL'', ''EPSILON'' :These are the direction of maximum polarization, defined with the beam in the fiducial orientation described above, that is, before rotation onto the detector position, and the cross-polarization contamination (or leakage).  These values are determined from ground-based measurements.
  
−
The detector parameter data are given in the form of a table giving the parameter values for each detector. The table columns are:
+
; Beam parameters - ''FWHM'', ''ELLIPTICITY'', ''POSANG'' : These are the mean FWHM of the scanning beam (in arcmin, the beam ellipticity (no units), and the position angle of the beam major axis. The scanning beam is that recovered from the observation of bright planets; details in [[Beams]] section.
  
−
; Channel identification : For HFI these will be of the form 100-1a, where the last letter is applied to the PSBs only, and for LFI they will have the form 27M or 18S. There
+
; Noise parameters - ''NET_TOT'', ''NET_WHT'', ''F_KNEE'', ''ALPHA'' : Two NETs are given: one determined from the total noise (rms of the noise timeline) and one determined from the white noise level of the noise spectrum.  The ''F_KNEE'' and ''ALPHA'' parameters are the frequency where the ''1/f'' noise component meets the white noise level, and the slope of the former.  The NETs are in units of Kcmb or MJy/sr * sqrt(s). These values are determined from the signal timelines as described in [[TOI processing|TOI processing]] chapter.
  
−
will include data for its 52 bolometers. F, and will include data for its 22 .
+
In the HFI RIMO, this table includes entries for the RTS bolometers (143-8 and 545-3), which are approximate or 0.00 when not evaluated.
  
 +
-->
  
 
== 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.  It is written into a BINTABLE extension named ''MAP_PARAMS'' whose structure is different for HFI and LFI and is as follows. The noise description below is very simplified; a more accurate rendition can be obtained from the half-ring maps.  Regarding the characterization of systematics, the user should use the survey differences.
 +
 +
=== HFI ===
 +
 +
; ''FREQUENCY'' (String) : a 3-digit string giving the reference frequency in GHz, i.e., of the form ''217''
 +
; ''OMEGA_F'', ''OMEGA_F_ERR'' (Real*4) : the full beam solid angle and its uncertainty, in armin<sup>2</sup>
 +
; ''OMEGA_1'', ''OMEGA_1_DISP'' (Real*4) : the beam solid angle out to 1FWHM, and its dispersion, in arcmin<sup>2</sup>
 +
; ''OMEGA_2'', ''OMEGA_2_DISP'' (Real*4) : the beam solid angle out to 2FWHM, and its dispersion, in arcmin<sup>2</sup>
 +
; ''FWHM'' (Real*4) : FWHM of a Gaussian beam having the same (total) solid angle, in armin<sup>2</sup>. This is the best value for source flux determination
 +
; ''FWHMGAUS'' (Real*4) : FWHM derived from best Gaussian fit to beam maps, in armin<sup>2</sup>. This is the best value for source identification
 +
; ''NOISE'' (Real*4) : This is the typical noise/valid observation sample as derived from the high-''l'' spectra of the half-ring maps, in the units of the corresponding 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 [[Beams]].
 +
 +
=== LFI ===
 +
 +
; ''FREQUENCY'' (String) : a 3-digit string giving the reference frequency in GHz, i.e., of the form ''030, 044, 070''
 +
; ''FWHM'' (Real*8) : FWHM of a Gaussian beam having the same (total) solid angle, in arcmin
 +
; ''NOISE'' (Real*8) : This is the average noise in T<math>\cdot</math>s<sup>1/2</sup>
 +
; ''CENTRALFREQ'' (Real*4) : This is the average central frequency in GHz
 +
; ''FWHM_EFF'', ''FWHM_EFF_SIGMA'' (Real*4) : This is the average FWHM of the effective beam, in arcmin, and its dispersion
 +
; ''ELLIPTICITY_EFF'', ''ELLIPTICITY_EFF_SIGMA'' (Real*4) : This is the average ellipticity and its dispersion
 +
; ''SOLID_ANGLE_EFF'', ''SOLID_ANGLE_EFF_SIGMA'' (Real*4) : This is the average full beam solid angle, in arcmin<sup>2</sup>, and its dispersion
  
 +
== 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 {{PlanckPapers|planck2013-p03d}}.  The bandpasses are given as 4-column tables containing:
 +
 +
=== HFI ===
 +
 +
; ''WAVENUMBER'' (Real*4) : the wavenumber in cm-1, conversion to GHz is accomplished by multiplying by <math>10^{-7}c</math> [mks].
 +
; ''TRANSMISSION'' (Real*4) : the transmission (normalized to 1 at the max for HFI)
 +
; ''ERROR'' (Real*4) : the statistical <math>1\sigma</math> uncertainty for the transmission profile.
 +
; ''FLAG'' (Integer) : 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 {{PlanckPapers|planck2013-p03a}}{{PlanckPapers|planck2013-p03d}}.
 +
 +
The number of rows will differ among the different extensions, but are the same, by construction, within each extension.  Tables with the unit conversion coefficients and color correction factors for the HFI detectors (and LFI in some instances), including uncertainty estimates based on the uncertainty of the HFI detector spectral response are given in [[UC_CC_Tables | this appendix]].
 +
 +
=== LFI ===
 +
 +
; ''WAVENUMBER'' (Real*8) : the wavenumber in GHz.
 +
; ''TRANSMISSION'' (Real*8) : the transmission (normalized to have an integral of 1 for LFI)
 +
; ''UNCERTAINITY'' (Real*4) : the statistical <math>1\sigma</math> uncertainty for the transmission profile (not provided for LFI)
 +
; ''FLAG'' (Character) : a flag, not used by now by the LFI
 +
 +
The number of rows will differ among the different extensions, but are the same, by construction, within each extension.
 +
 +
<!--
 
== Detector noise spectra ==
 
== Detector noise spectra ==
  
 +
There are no detector-level noise data in the RIMO for this release
 +
 +
; HFI: these are the ring noise spectra averaged for rings NN to MM in order to give a representative spectrum. The spectra of all 50 valid bolometers are given in a single table.
 +
; LFI : TBW
 +
 +
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 (for HFI only) of one (or two) frequency maps or detset maps used in the likelihood.  Here they are:
 +
 +
; ''For the HFI'':
 +
* 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
 +
 +
; ''For the LFI'':
 +
* the 3 LFI frequency channels, producing 3 extensions
 +
** 30, 44, 70
 +
 +
 +
and the extension names are of the form ''BEAMWF_U1XU2'' where U1 and U2 are one (possibly the same) detection unit from one of the main groups above (i.e. there are no cross products between detsets and frequency channels, or between HFI and LFI). Each extension contains the columns:
 +
; ''NOMINAL'' (Real*4) : the beam window function proper,
 +
; ''EIGEN_n'' (Real*4, n=1-5 for the HFI, n=1-4 for the LFI): the five/four corresponding error modes.
 +
 +
and the following keywords give further information, only for the HFI:
 +
; ''NMODES'' (Integer) : the number of EIGEN_* modes,
 +
; ''LMIN'' and ''LMAX'' (Integer) : the starting and ending (both included) multipoles of the vectors NOMINAL and EIGEN_*
 +
; ''LMIN_EM'' and ''LMAX_EM'' (Integer) : that give the range of the valid samples of the EIGEN_* vectors. Here ''LMAX_EM'' is always less than or equal to ''LMAX''. On the range ''LMAX_EM''+1 to ''LMAX'' the values of EIGEN_* are set to NaN, while the values of NOMINAL only are a Gaussian extrapolation of the lower multipole window function, only provided for convenience.
 +
; ''CORRMAT'' (string) : the name of the extension containing the corresponding beam correlation matrix
 +
 +
== Beam Correlation Matrix ==
 +
 +
Two beam correlation matrices are given for the HFI, in two ''IMAGE'' extensions:
 +
; ''CORRBEAM_FREQ'' (Real*8) : for the frequency channels (21 units), 105x015 pixel matrix,
 +
; ''CORRBEAM_DSET'' (Real*8) : for the detsets (351 units), 1755x1755 pixel matrix
 +
Each is a symmetric matrix with 1-valued diagonal, made of NBEAMS*NBEAMS blocks, each block being NMODES*NMODES in size.  The n$^{th}$ row- (and column-) block entry relates to the B(l) model whose name is indicated in ROWn = BEAMWF_U1XU2 keywords, and the corresponding eigenmodes are stored in a HDU of the same name. 
 +
 +
Each extension contains also the following keywords:
 +
; ''NDETS'' (Integer) : the number of detector units
 +
; ''NBEAMS'' (Integer) : the number of beams = NSETS * (NSETS+1) / 2
 +
; ''NMODES'' (Integer) : here 5
 +
; ''L_PLUS'' (Integer) : Eigenmode > 0 to break degeneracies
 +
; ''BLOCKn'' (string) : for n=1-NBEAMS, gives the name of the extension containing the beam WF and error eigenmodes for the nth block
 +
and some other ones for internal data checking and traceability
 +
 +
No beam correlation matrices are produced by the LFI by now.
 +
 +
==Appendices==
 +
 +
* [[UC_CC_Tables | Unit correction and color correction tables]]
 +
 +
 +
== References ==
 +
 +
<References />
  
  
−
== FITS file structure ==
+
[[Category:Mission products|003]]

Latest revision as of 16:42, 23 July 2014

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
Image 
namely 2-D "flat" array, to give, e.g., the beam correlation matrices

The FITS file begins with primary header that contains some keywords that mainly for internal use and no data. The different types of data are written into different BINTABLE (for parameters and tables) or IMAGE (for 2-D arrays) extensions, as described below.

File Names[edit]

HFI
HFI_RIMO_R1.10.fits
LFI
LFI_RIMO_R1.12.fits


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. It is written into a BINTABLE extension named MAP_PARAMS whose structure is different for HFI and LFI and is as follows. The noise description below is very simplified; a more accurate rendition can be obtained from the half-ring maps. Regarding the characterization of systematics, the user should use the survey differences.

HFI[edit]

FREQUENCY (String) 
a 3-digit string giving the reference frequency in GHz, i.e., of the form 217
OMEGA_F, OMEGA_F_ERR (Real*4) 
the full beam solid angle and its uncertainty, in armin2
OMEGA_1, OMEGA_1_DISP (Real*4) 
the beam solid angle out to 1FWHM, and its dispersion, in arcmin2
OMEGA_2, OMEGA_2_DISP (Real*4) 
the beam solid angle out to 2FWHM, and its dispersion, in arcmin2
FWHM (Real*4) 
FWHM of a Gaussian beam having the same (total) solid angle, in armin2. This is the best value for source flux determination
FWHMGAUS (Real*4) 
FWHM derived from best Gaussian fit to beam maps, in armin2. This is the best value for source identification
NOISE (Real*4) 
This is the typical noise/valid observation sample as derived from the high-l spectra of the half-ring maps, in the units of the corresponding 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 Beams.

LFI[edit]

FREQUENCY (String) 
a 3-digit string giving the reference frequency in GHz, i.e., of the form 030, 044, 070
FWHM (Real*8) 
FWHM of a Gaussian beam having the same (total) solid angle, in arcmin
NOISE (Real*8) 
This is the average noise in T[math]\cdot[/math]s1/2
CENTRALFREQ (Real*4) 
This is the average central frequency in GHz
FWHM_EFF, FWHM_EFF_SIGMA (Real*4) 
This is the average FWHM of the effective beam, in arcmin, and its dispersion
ELLIPTICITY_EFF, ELLIPTICITY_EFF_SIGMA (Real*4) 
This is the average ellipticity and its dispersion
SOLID_ANGLE_EFF, SOLID_ANGLE_EFF_SIGMA (Real*4) 
This is the average full beam solid angle, in arcmin2, and its dispersion

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 Planck-2013-IX[1]. The bandpasses are given as 4-column tables containing:

HFI[edit]

WAVENUMBER (Real*4) 
the wavenumber in cm-1, conversion to GHz is accomplished by multiplying by [math]10^{-7}c[/math] [mks].
TRANSMISSION (Real*4) 
the transmission (normalized to 1 at the max for HFI)
ERROR (Real*4) 
the statistical [math]1\sigma[/math] uncertainty for the transmission profile.
FLAG (Integer) 
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 Planck-2013-XIII[2]Planck-2013-IX[1].

The number of rows will differ among the different extensions, but are the same, by construction, within each extension. Tables with the unit conversion coefficients and color correction factors for the HFI detectors (and LFI in some instances), including uncertainty estimates based on the uncertainty of the HFI detector spectral response are given in this appendix.

LFI[edit]

WAVENUMBER (Real*8) 
the wavenumber in GHz.
TRANSMISSION (Real*8) 
the transmission (normalized to have an integral of 1 for LFI)
UNCERTAINITY (Real*4) 
the statistical [math]1\sigma[/math] uncertainty for the transmission profile (not provided for LFI)
FLAG (Character) 
a flag, not used by now by the LFI

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 (for HFI only) of one (or two) frequency maps or detset maps used in the likelihood. Here they are:

For the HFI
  • 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
For the LFI
  • the 3 LFI frequency channels, producing 3 extensions
    • 30, 44, 70


and the extension names are of the form BEAMWF_U1XU2 where U1 and U2 are one (possibly the same) detection unit from one of the main groups above (i.e. there are no cross products between detsets and frequency channels, or between HFI and LFI). Each extension contains the columns:

NOMINAL (Real*4) 
the beam window function proper,
EIGEN_n (Real*4, n=1-5 for the HFI, n=1-4 for the LFI)
the five/four corresponding error modes.

and the following keywords give further information, only for the HFI:

NMODES (Integer) 
the number of EIGEN_* modes,
LMIN and LMAX (Integer) 
the starting and ending (both included) multipoles of the vectors NOMINAL and EIGEN_*
LMIN_EM and LMAX_EM (Integer) 
that give the range of the valid samples of the EIGEN_* vectors. Here LMAX_EM is always less than or equal to LMAX. On the range LMAX_EM+1 to LMAX the values of EIGEN_* are set to NaN, while the values of NOMINAL only are a Gaussian extrapolation of the lower multipole window function, only provided for convenience.
CORRMAT (string) 
the name of the extension containing the corresponding beam correlation matrix

Beam Correlation Matrix[edit]

Two beam correlation matrices are given for the HFI, in two IMAGE extensions:

CORRBEAM_FREQ (Real*8) 
for the frequency channels (21 units), 105x015 pixel matrix,
CORRBEAM_DSET (Real*8) 
for the detsets (351 units), 1755x1755 pixel matrix

Each is a symmetric matrix with 1-valued diagonal, made of NBEAMS*NBEAMS blocks, each block being NMODES*NMODES in size. The n$^{th}$ row- (and column-) block entry relates to the B(l) model whose name is indicated in ROWn = BEAMWF_U1XU2 keywords, and the corresponding eigenmodes are stored in a HDU of the same name.

Each extension contains also the following keywords:

NDETS (Integer) 
the number of detector units
NBEAMS (Integer) 
the number of beams = NSETS * (NSETS+1) / 2
NMODES (Integer) 
here 5
L_PLUS (Integer) 
Eigenmode > 0 to break degeneracies
BLOCKn (string) 
for n=1-NBEAMS, gives the name of the extension containing the beam WF and error eigenmodes for the nth block

and some other ones for internal data checking and traceability

No beam correlation matrices are produced by the LFI by now.

Appendices[edit]


References[edit]

  1. ↑ 1.01.1 Planck 2013 results: HFI spectral response, Planck Collaboration 2013 IX, A&A, in press, (2014).
  2. ↑ Planck 2013 results: Galactic CO emission as seen by Planck, Planck Collaboration XIII, A&A, in press, (2014).

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

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