CMB spectra and likelihood code

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CMB spectra[edit]

General description[edit]

TT[edit]

The Planck best-fit CMB temperature power spectrum, shown in the figure below, covers the wide range of multipoles ℓ = 2-2508. Over the multipole range ℓ = 2-29, the power spectrum is derived from the "Commander" component-separation algorithm applied to the combination of Planck 2015 temperature data between 30 and 857 GHz, the 9-year WMAP sky maps, and the 408-MHz Haslam et al. (1982) survey, including 93% of the sky (Planck-2015-A10[1]). The asymmetric error bars associated with this spectrum are the 68% confidence limits and include the uncertainties due to foreground subtraction.

For multipoles equal or greater than ℓ = 30, instead, the spectrum is derived from the "Plik" likelihood Planck-2015-A11[2] by optimally combining the spectra in the frequency range 100-217 GHz, and correcting them for unresolved foregrounds using the best-fit foreground solution from a Planck TT+lowP ΛCDM run. Associated 1σ errors include beam uncertainties. Both Commander and Plik are described in more detail in the sections below.

Planck 2015 TT power spectrum. The x-axis is logarithmic up to ℓ = 30 and linear at higher ℓ. The red line is the Planck best-fit primordial power spectrum (cf. Planck TT+lowP in table 3 of Planck-2015-A15[3]). Residuals with respect to this model are shown in the lower panel. The error bars show ±1σ uncertainties.

TE, EE, and TB, EB, BB[edit]

The Planck best-fit CMB polarization and temperature-polarization cross-correlation power spectra, shown in the figure below, cover the multipole range ℓ = 2-1996. The data points relative to the multipole range ℓ = 2-29 are quadratic maximum likelihood (QML) estimates from foreground-cleaned Planck 70-GHz Q and U Stokes parameter maps using 46% of the sky (the same maps that are used in the "lowP" likelihood, see Planck-2015-A11[2]). In the range ℓ = 2-29, we also release the BB, TB, and EB power spectra derived from the same maps (for the cross-spectra involving temperature, the Commander map is always used). Symmetric error bars are given as the 68% confidence intervals as derived from the Fisher information matrix of the estimates. Analogously to the TT case, the ℓ ≥ 30 spectrum is derived from the Plik likelihood Planck-2015-A11[2] by optimally combining the spectra in the frequency range 100-217 GHz, and correcting them for unresolved foregrounds using the best-fit foreground solution from a Planck TT,TE,EE+lowP ΛCDM run.

Planck 2015 EE power spectrum. The red line is the Planck best-fit primordial power spectrum (cf. Planck TT+lowP in table 3 of Planck-2015-A13[3]). Residuals with respect to this model are shown in the lower panel. The error bars show ±1σ uncertainties.
Planck 2015 TE power spectrum. The red line is the Planck best-fit primordial power spectrum (cf. Planck TT+lowP in table 3 of Planck-2015-A13[3]). Residuals with respect to this model are shown in the lower panel. The error bars show ±1σ uncertainties.

Production process[edit]

The ℓ < 30 part of the Planck TT power spectrum is derived from the Commander approach, which implements Bayesian component separation in pixel space, fitting a parametric model to the data by sampling the posterior distribution for the model parameters (Planck-2015-A10[1]). The power spectrum at any multipole ℓ is given as the maximum probability point for the posterior C distribution, marginalized over the other multipoles, and the error bars are from the 68% confidence level; see Planck-2015-A10[1]. The polarization spectra (EE, TE, BB, TB, EB) are estimated from maps of the Planck 70 GHz channel, cleaned from polarized synchrotron emission using the 30 GHz channel as a template and from polarized dust emission using the 353 GHz channel; see Sect.2 of Planck-2015-A11[2] for details about the foreground cleaning procedure. The pixel-pixel (map level) noise covariance matrix has been estimated from the timelines and corrected to account for foreground cleaning. The QML code Bolpol has been used to estimate the power spectra and their Fisher matrix from the cleaned map and covariance matrix, after imposing a Galactic mask that makes 43% of the full sky available to analysis (see again Planck-2015-A11[2]). The symmetric 68% error bars have been derived from the resulting Fisher matrix and include contributions from cosmic variance, noise, and foreground associated errors.

The ℓ ≥ 30 part of the TT, TE, and EE power spectra have been derived by the Plik likelihood, a code that implements a pseudo-C based technique, extensively described in section 2.2 and the appendix of Planck-2013-XV[4], and more recently in Planck-2015-A11[2]. Frequency spectra are computed as cross-spectra between half-mission maps. Mask and multipole range choices for each frequency spectrum are summarized in section 3.3 of Planck-2015-A13[3] and in Planck-2015-A11[2]. The final power spectrum is an optimal combination of the 100, 143, 143×217, and 217 GHz spectra, corrected for the best-fit unresolved foregrounds and inter-frequency calibration factors, as derived from the full likelihood analysis (for TT we use the best-fit solutions for the nuisance parameters from the Planck+TT+lowP data combination, while for TE and EE we use the best fit from Planck+TT+lowP, cf. table 3 of Planck-2015-A13[3]). A thorough description of the models of unresolved foregrounds is given in Planck-2015-A11[2]. The spectrum covariance matrix accounts for cosmic variance and noise contributions, together with beam uncertainties. The ℓ ≥ 30 CMB TT spectrum and associated covariance matrix are available in two formats.

  1. Unbinned: TT, 2479 bandpowers (ℓ = 30-2508); TE or EE, 1697 bandpowers (ℓ = 30-1996).
  2. Binned, in bins of Δℓ = 30: TT, 83 bandpowers; TE or EE, 66 bandpowers.

We bin the C power spectrum with a weight proportional to ℓ(ℓ+1), so that the Cb binned bandpower centred on ℓb is [math]\\ C_{\ell_b}=\Sigma_{\ell \in b} w_{\ell_b\ell} C_\ell, \quad \text{with} \quad w_{\ell_b\ell}=\frac{\ell (\ell+1)}{\Sigma_{\ell \in b} \ell (\ell+1)}.\\[/math] Equivalently, using the matrix formalism, we can construct the binning matrix B as [math]\\ B_{\ell_b \ell}=w_{\ell_b\ell}, \\ [/math] where B is an nb×n matrix, with nb=83 being the number of bins and n=2479 the number of unbinned multipoles. Thus [math] \\ {\bf C}_\mathrm{binned}=B \, {\bf C}, \\ \mathrm{cov_\mathrm{binned}}= B\, \mathrm{cov}\, B^{\rm T}, \\ \ell_b=B\, \ell .\\ [/math] Here, [math] {\bf C}_{\rm binned}\, ({\bf C})[/math] is the vector containing all the binned (unbinned) C bandpowers, [math]\mathrm{cov}[/math] is the covariance matrix, and ℓb is the weighted average multipole in each bin. Note that following this definition, ℓb can be a non-integer. The binned Db power spectrum is then calculated as [math] \\ D_{\ell_b}=\frac{\ell_b (\ell_b+1)}{2\pi} C_{\ell_b}. [/math]

Inputs[edit]

Low-ℓ spectrum (ℓ<30):
  • Planck 30 and 44 GHz frequency maps;
  • Planck 70 to 857 GHz detector and detector-set maps;
  • 9-year WMAP temperature sky maps between 23 and 94 GHz;
  • 408-MHz survey of Haslam et al. (1982);
  • Commander χ2-based LM93 confidence mask (Planck-2015-A10[1]).
High-ℓ spectrum (30≤ℓ≤2508):

File names and meta-data[edit]

The CMB spectra and their uncertainties are distributed in a single multi-extension FITS file named COM_PowerSpect_CMB_R2.nn.fits.

  • R2.00 contains (unbinned) TT spectra for low ℓ and TT, TE and EE spectra at high ℓ, both binned and unbinned (7 extensions).
  • R2.01 corrects a small error in the effective ℓ of the bin of the binned data, which was truncated to an integer. Since these are weighted averages of the ℓ's used in a particular bin, they should be a reals.
  • R2.02 contains low ℓ *E and *B spectra in addition to the TT spectra (5 additional extensions for a total of 12 extensions).

Further details on the data columns are given below (the extension numbers correspond to the R2.02 release).

1. TT low-ℓ, unbinned (TTLOLUNB)
with the low-ℓ part of the spectrum, not binned, and for ℓ=2-29. The table columns are:
  1. ELL (integer), multipole number;
  2. D_ELL (float), D as described above;
  3. ERRUP (float), the upward uncertainty;
  4. ERRDOWN (float), the downward uncertainty.
2. TE low-ℓ, unbinned (TTLOLUNB)
with the low-ℓ part of the spectrum, not binned, and for ℓ=2-29. The table columns are:
  1. ELL (integer), multipole number;
  2. D_ELL (float), D as described above;
  3. ERRUP (float), the upward uncertainty;
  4. ERRDOWN (float), the downward uncertainty.
3. EE low-ℓ, unbinned (TTLOLUNB)
with the low-ℓ part of the spectrum, not binned, and for ℓ=2-29. The table columns are:
  1. ELL (integer), multipole number;
  2. D_ELL (float), D as described above;
  3. ERRUP (float), the upward uncertainty;
  4. ERRDOWN (float), the downward uncertainty.
4. TB low-ℓ, unbinned (TTLOLUNB)
with the low-ℓ part of the spectrum, not binned, and for ℓ=2-29. The table columns are:
  1. ELL (integer), multipole number;
  2. D_ELL (float), D as described above;
  3. ERRUP (float), the upward uncertainty;
  4. ERRDOWN (float), the downward uncertainty.
5. EB low-ℓ, unbinned (TTLOLUNB)
with the low-ℓ part of the spectrum, not binned, and for ℓ=2-29. The table columns are:
  1. ELL (integer), multipole number;
  2. D_ELL (float), D as described above;
  3. ERRUP (float), the upward uncertainty;
  4. ERRDOWN (float), the downward uncertainty.
6. BB low-ℓ, unbinned (TTLOLUNB)
with the low-ℓ part of the spectrum, not binned, and for ℓ=2-29. The table columns are:
  1. ELL (integer), multipole number;
  2. D_ELL (float), D as described above;
  3. ERRUP (float), the upward uncertainty;
  4. ERRDOWN (float), the downward uncertainty.
7. TT high-ℓ, binned (TTHILBIN)
with the high-ℓ part of the spectrum, binned into 83 bins covering 〈ℓ〉= 47-2499 in bins of width ℓ=30 (with the exception of the last bin that is smaller). The table columns are:
  1. ELL (float), mean multipole number of bin;
  2. L_MIN (integer), lowest multipole of bin;
  3. L_MAX (integer), highest multipole of bin;
  4. D_ELL (float), D as described above;
  5. ERR (float), the uncertainty.
8. TT high-ℓ unbinned (TTHILUNB)
with the high-ℓ part of the spectrum, unbinned, in 2979 bins covering 〈ℓ〉= 30-2508. The table columns are:
  1. ELL (integer), multipole;
  2. D_ELL (float), D as described above;
  3. ERR (float), the uncertainty.
9. TE high-ℓ, binned (TEHILBIN)
with the high-ℓ part of the spectrum, binned into 83 bins covering 〈ℓ〉= 47-1988 in bins of width ℓ=30 (with the exception of the last bin that is smaller). The table columns are:
  1. ELL (float), mean multipole number of bin;
  2. L_MIN (integer), lowest multipole of bin;
  3. L_MAX (integer), highest multipole of bin;
  4. D_ELL (float), D as described above;
  5. ERR (float), the uncertainty.
10. TE high-ℓ, unbinned (TEHILUNB)
with the high-ℓ part of the spectrum, unbinned, in 2979 bins covering 〈ℓ〉= 30-1996. The table columns are:
  1. ELL (integer), multipole;
  2. D_ELL (float), D as described above;
  3. ERR (float), the uncertainty.
11. EE high-ℓ, binned (EEHILBIN)
with the high-ℓ part of the spectrum, binned into 83 bins covering 〈ℓ〉= 47-1988 in bins of width ℓ=30 (with the exception of the last bin that is smaller). The table columns are:
  1. ELL (float), mean multipole number of bin;
  2. L_MIN (integer), lowest multipole of bin;
  3. L_MAX (integer), highest multipole of bin;
  4. D_ELL (float), D as described above;
  5. ERR (float), the uncertainty.
12. EE high-ℓ, unbinned (EEHILUNB)
with the high-ℓ part of the spectrum, unbinned, in 2979 bins covering 〈ℓ〉= 30-1996. The table columns are:
  1. ELL (integer), multipole;
  2. D_ELL (float), D as described above;
  3. ERR (float), the uncertainty.

The spectra give D = ℓ(ℓ+1)C / 2π in units of μK2. The covariance matrices of the spectra will be released at a later time.

The CMB spectra are also given in seven simple text files, corresponding to each of the FITS file BINTABLE extensions described above.

Likelihood[edit]

The 2018 Likelihood code will be released at a later time.

Previous Releases: (2015) and (2013) CMB spectrum and Likelihood[edit]

Expand

2015 CMB spectrum and Likelihood

Expand

2013 CMB spectrum and Likelihood


References[edit]

  1. Jump up to: 1.01.11.21.31.41.51.61.71.81.9 Planck 2015 results. X. Diffuse component separation: Foreground maps, Planck Collaboration, 2016, A&A, 594, A10.
  2. Jump up to: 2.002.012.022.032.042.052.062.072.082.092.102.112.122.132.142.152.162.172.182.192.202.212.222.232.242.25 Planck 2015 results. XI. CMB power spectra, likelihoods, and robustness of cosmological parameters, Planck Collaboration, 2016, A&A, 594, A11.
  3. Jump up to: 3.003.013.023.033.043.053.063.073.083.093.103.11 Planck 2015 results. XIII. Cosmological parameters, Planck Collaboration, 2016, A&A, 594, A13.
  4. Jump up to: 4.004.014.024.034.044.054.064.074.084.094.104.114.124.13 Planck 2013 results. XV. CMB power spectra and likelihood, Planck Collaboration, 2014, A&A, 571, A15.
  5. Jump up to: 5.05.1 Planck 2015 results. VII. High Frequency Instrument data processing: Time-ordered information and beam processing, Planck Collaboration, 2016, A&A, 594, A7.
  6. Jump up Planck 2015 results. XII. Full Focal Plane Simulations, Planck Collaboration, 2016, A&A, 594, A12.
  7. Jump up to: 7.07.1 Planck 2015 results. XV. Gravitational Lensing, Planck Collaboration, 2016, A&A, 594, A15.
  8. Jump up to: 8.08.18.2 Planck 2013 results. XI. Component separation, Planck Collaboration, 2014, A&A, 571, A11.
  9. Jump up to: 9.09.19.29.3 Planck 2013 results. XVI. Cosmological parameters, Planck Collaboration, 2014, A&A, 571, A16.
  10. Jump up to: 10.010.110.2 Planck 2013 results. XVII. Gravitational lensing by large-scale structure, Planck Collaboration, 2014, A&A, 571, A17.
  11. Jump up to: 11.011.111.2 The Atacama Cosmology Telescope: likelihood for small-scale CMB data, J. Dunkley, E. Calabrese, J. Sievers, G. E. Addison, N. Battaglia, E. S. Battistelli, J. R. Bond, S. Das, M. J. Devlin, R. Dunner, J. W. Fowler, M. Gralla, A. Hajian, M. Halpern, M. Hasselfield, A. D. Hincks, R. Hlozek, J. P. Hughes, K. D. Irwin, A. Kosowsky, T. Louis, T. A. Marriage, D. Marsden, F. Menanteau, K. Moodley, M. Niemack, M. R. Nolta, L. A. Page, B. Partridge, N. Sehgal, D. N. Spergel, S. T. Staggs, E. R. Switzer, H. Trac, E. Wollack, ArXiv e-prints, (2013).
  12. Jump up to: 12.012.1 A Measurement of the Damping Tail of the Cosmic Microwave Background Power Spectrum with the South Pole Telescope, R. Keisler, C. L. Reichardt, K. A. Aird, B. A. Benson, L. E. Bleem, J. E. Carlstrom, C. L. Chang, H. M. Cho, T. M. Crawford, A. T. Crites, T. de Haan, M. A. Dobbs, J. Dudley, E. M. George, N. W. Halverson, G. P. Holder, W. L. Holzapfel, S. Hoover, Z. Hou, J. D. Hrubes, M. Jo, L. Knox, A. T. Lee, E. M. Leitch, M. Lueker, D. Luong-Van, J. J. McMahon, J. Mehl, S. S. Meyer, M. Millea, J. J. Mohr, T. E. Montroy, T. Natoli, S. Padin, T. Plagge, C. Pryke, J. E. Ruhl, K. K. Schaffer, L. Shaw, E. Shirokoff, H. G. Spieler, Z. Staniszewski, A. A. Stark, K. Story, A. van Engelen, K. Vanderlinde, J. D. Vieira, R. Williamson, O. Zahn, ApJ, 743, 28, (2011).
  13. Jump up to: 13.013.1 A Measurement of Secondary Cosmic Microwave Background Anisotropies with Two Years of South Pole Telescope Observations, C. L. Reichardt, L. Shaw, O. Zahn, K. A. Aird, B. A. Benson, L. E. Bleem, J. E. Carlstrom, C. L. Chang, H. M. Cho, T. M. Crawford, A. T. Crites, T. de Haan, M. A. Dobbs, J. Dudley, E. M. George, N. W. Halverson, G. P. Holder, W.L. Holzapfel, S. Hoover, Z. Hou, J. D. Hrubes, M. Joy, R. Keisler, L. Knox, A. T. Lee, E. M. Leitch, M. Lueker, D. Luong-Van, J. J. McMahon, J. Mehl, S. S. Meyer, M. Millea, J. J. Mohr, T. E. Montroy, T. Natoli, S. Padin, T. Plagge, C. Pryke, J. E. Ruhl, K. K. Schaffer, E. Shirokoff, H. G. Spieler, Z. Staniszewski, A. A. Stark, K. Story, A. van Engelen, K. Vanderlinde, J. D. Vieira, R. Williamson, ApJ, 755, 70, (2012).
  14. Jump up Planck 2013 results. VII. HFI time response and beams, Planck Collaboration, 2014, A&A, 571, A7.

Cosmic Microwave background

Flexible Image Transfer Specification

(Planck) Low Frequency Instrument

(Planck) High Frequency Instrument

Sunyaev-Zel'dovich

Full-Width-at-Half-Maximum