Summary of LFI data characteristics

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Quantification of the performance of LFI is summarized in Table 1 below. All the details can be found in the LFI data processing paper Planck-2015-A02[1].

Table 1. LFI performance parameters
Parameter 30 GHz 44 GHz 70 GHz
Centre frequency [GHz] 28.4 44.1 70.4
Scanning beam FWHMa [arcmin] 33.10 27.94 13.08
Scanning beam ellipticitya 1.37 1.25 1.27
Effective beam FWHMb [arcmin] 32.29 27.00 13.21
White noise level in mapc [μKCMB] *TBD *TBD *TBD
White noise level in timelinesd [μKCMB s1/2] 148.1 174.2 152.0
fkneed [mHz] 114.1 52.4 19.7
1/f sloped -0.92 -0.88 -1.20
Overall calibration uncertaintye [%] 0.35 0.26 0.29
Systematic effects uncertainty in Stokes I f [μKCMB] 0.88 1.97 1.87
Systematic effects uncertainty in Stokes Q f [μKCMB] 1.11 1.14 2.25
Systematic effects uncertainty in Stokes U f [μKCMB] 0.95 1.29 2.22

a Determined by fitting Jupiter observations directly in the timelines.

b Calculated from the main beam solid angle of the effective beam, Ωeff = mean(Ω). These values are used in the source extraction pipeline (Planck-2015-A35[2]).

c White noise per pixel computed from half-ring difference maps. These values are within 1% of the white noise sensitivity computed directly on the timelines, taking into account the actual integration time represented in the maps.

d Values derived from fitting noise spectra.

e Sum of the error on the estimation of the calibration constant (0.25 %) and the square root of the squared sum of the following errors: beam uncertainty; sidelobe convolution effect; and unknown systematics as measured from the power spectrum at 50 < ℓ < 250, see Planck-2015-A04[3].

f Peak-to-peak difference between 99% and 1% quantities in the pixel value distributions from simulated maps, see Planck-2015-A02[1].


  1. 1.01.1 Planck 2015 results. II. LFI processing, Planck Collaboration, 2016, A&A, 594, A2.
  2. Planck 2015 results. XXVI. The second Planck catalogue of compact sources, Planck Collaboration, 2016, A&A, 594, A26.
  3. Planck 2015 results. IV. LFI beams and window functions, Planck Collaboration, 2016, A&A, 594, A4.

(Planck) Low Frequency Instrument


Cosmic Microwave background

To be defined / determined