Summary of LFI data characteristics

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The LFI performance are summarized in Table 1 below. All the details can be found in the LFI data processing paper Planck-2015-A03[1].

Table 1. LFI performance parameters
Parameter 30 GHz 44 GHz 70 GHz
Center frequency [GHz] 28.4 44.1 70.4
Scanning beam FWHM[math]^{\rm a}[/math] [arcmin] 33.10 27.94 13.08
Scanning beam ellipticity[math]^{\rm a}[/math] 1.37 1.25 1.27
Effective beam FWHM[math]^{\rm b}[/math] [arcmin] 32.29 27.00 13.21
White noise level in map[math]^{\rm c}[/math] [[math]\mu[/math]K[math]_{CMB}[/math]] *TBD *TBD *TBD
White noise level in timelines[math]^{\rm d}[/math] [[math]\mu[/math]K[math]_{CMB} \;s^{1/2}[/math]] 148.1 174.2 152.0
f[math]_{\rm knee}^{\rm d}[/math] [mHz] 114.1 52.4 19.7
1/[math]f[/math] slope[math]^{\rm d}[/math] -0.92 -0.88 -1.20
Overall calibration uncertainty[math]^{\rm e}[/math] [%] 0.35 0.26 0.29
Systematic effects uncertainty in Stokes [math]I^{\rm f}[/math] [[math]\mu[/math]K[math]_{CMB}[/math]] 0.88 1.97 1.87
Systematic effects uncertainty in Stokes [math]Q^{\rm f}[/math] [[math]\mu[/math]K[math]_{CMB}[/math]] 1.11 1.14 2.25
Systematic effects uncertainty in Stokes [math]U^{\rm f}[/math] [[math]\mu[/math]K[math]_{CMB}[/math]] 0.95 1.29 2.22

[math]^{\rm a}[/math] Determined by fitting Jupiter observations directly in the timelines.

[math]^{\rm b}[/math] Calculated from the main beam solid angle of the effective beam, [math]\Omega_{\rm eff} = \hbox{mean}(\Omega)[/math]. These values are used in the source extraction pipeline Planck-2015-A35[2].

[math]^{\rm c}[/math] 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.

[math]^{\rm d}[/math] Values derived from fitting noise spectra.

[math]^{\rm e}[/math] 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 [math]50 \lt \ell \lt 250 [/math], see Planck-2015-A05[3].

[math]^{\rm f}[/math] Peak-to-peak difference between 99% and 1% quantities in the pixel value distributions from simulated maps, see Planck-2015-A03[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