Difference between revisions of "CMB spectrum & Likelihood Code"
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===General description=== | ===General description=== | ||
+ | <span style="color:red"> UPDATE COMMANDER</span> | ||
− | The Planck best-fit CMB temperature power spectrum, shown in figure below, covers the wide range of multipoles <math> \ell </math> = 2-2508. Over the multipole range <math> \ell </math> = 2–29, the power spectrum is derived from a component-separation algorithm, ''Commander'' | + | The Planck best-fit CMB temperature power spectrum, shown in figure below, covers the wide range of multipoles <math> \ell </math> = 2-2508. Over the multipole range <math> \ell </math> = 2–29, the power spectrum is derived from a component-separation algorithm, ''Commander'': applied to maps in the frequency range 30–353 GHz over 91% of the sky {{PlanckPapers|planck2013-p06}} . The asymmetric error bars associated to this spectrum are the 68% confidence limits and include the uncertainties due to foreground subtraction. For multipoles equal or greater than <math>\ell=30</math>, instead, the spectrum is derived from the ''Plik'' likelihood {{PlanckPapers|planck2014-a13}} by optimally combining the spectra in the frequency range 100-217 GHz, and correcting them for unresolved foregrounds. Associated 1-sigma errors include beam uncertainties. Both ''Commander'' and ''Plik'' are described in more details in the sections below. |
[[File: Planck2014 TT Dl NORES bin30 w180mm.jpeg|thumb|center|700px|'''CMB spectrum. Logarithmic x-scale up to <math>\ell=30</math>, linear at higher <math>\ell</math>; all points with error bars. The red line is the Planck best-fit primordial power spectrum (cf Planck TT+lowP in Table 3 of {{PlanckPapers|planck2014-a15}}). The blue shaded area shows the uncertainties due to cosmic variance alone.''']] | [[File: Planck2014 TT Dl NORES bin30 w180mm.jpeg|thumb|center|700px|'''CMB spectrum. Logarithmic x-scale up to <math>\ell=30</math>, linear at higher <math>\ell</math>; all points with error bars. The red line is the Planck best-fit primordial power spectrum (cf Planck TT+lowP in Table 3 of {{PlanckPapers|planck2014-a15}}). The blue shaded area shows the uncertainties due to cosmic variance alone.''']] | ||
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===Inputs=== | ===Inputs=== | ||
+ | <span style="color:red"> UPDATE COMMANDER</span> | ||
; Low-l spectrum (<math>\ell < 30</math>): | ; Low-l spectrum (<math>\ell < 30</math>): | ||
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; High-l spectrum (<math>30 < \ell < 2500</math>): | ; High-l spectrum (<math>30 < \ell < 2500</math>): | ||
− | * 100, 143, 143x217 and 217 GHz spectra and their covariance matrix (Sec. 3.3 {{PlanckPapers|planck2014- | + | * 100, 143, 143x217 and 217 GHz spectra and their covariance matrix (Sec. 3.3 {{PlanckPapers|planck2014-a15}}) |
− | * best-fit foreground templates and inter-frequency calibration factors (Table 3 of {{PlanckPapers|planck2014- | + | * best-fit foreground templates and inter-frequency calibration factors (Table 3 of {{PlanckPapers|planck2014-a15}}) |
− | * Beam transfer function uncertainties {{PlanckPapers|planck2014- | + | * Beam transfer function uncertainties {{PlanckPapers|planck2014-a08}} |
=== File names and Meta data === | === File names and Meta data === | ||
Revision as of 01:00, 4 February 2015
Contents
CMB spectra[edit]
General description[edit]
UPDATE COMMANDER
The Planck best-fit CMB temperature power spectrum, shown in figure below, covers the wide range of multipoles = 2-2508. Over the multipole range = 2–29, the power spectrum is derived from a component-separation algorithm, Commander: applied to maps in the frequency range 30–353 GHz over 91% of the sky Planck-2013-XII[1] . The asymmetric error bars associated to this spectrum are the 68% confidence limits and include the uncertainties due to foreground subtraction. For multipoles equal or greater than , 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. Associated 1-sigma errors include beam uncertainties. Both Commander and Plik are described in more details in the sections below.
![](/planckpla2015/images/thumb/b/b6/Planck2014_TT_Dl_NORES_bin30_w180mm.jpeg/700px-Planck2014_TT_Dl_NORES_bin30_w180mm.jpeg)
Production process[edit]
UPDATE COMMANDER The < 50 part of the Planck 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-2013-XII[1]. The power spectrum at any multipole is given as the maximum probability point for the posterior distribution, marginalized over the other multipoles, and the error bars are 68% confidence level Planck-2013-XV[4]. The > 30 part of the CMB temperature power spectrum has been derived by the Plik likelihood, a code that implements a pseudo-Cl based technique, extensively described in Sec. 2 and the Appendix of Planck-2013-XV[4]. 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, 143x217 and 217 GHz spectra, corrected for the best-fit unresolved foregrounds and inter-frequency calibration factors, as derived from the full likelihood analysis (cf Planck+TT+lowP in 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 > 30 CMB TT spectrum and associated covariance matrix are available in two formats:
- Unbinned, with 2479 bandpowers ( ).
- Binned, in bins of , with 83 bandpowers in total. We bin the power spectrum with a weight proportional to , so that the binned bandpower centered in is: Equivalently, using the matrix formalism, we can construct the binning matrix B as: where B is a matrix, with the number of bins and the number of unbinned multipoles. Thus: Here, is the vector containing all the binned (unbinned) bandpowers, is the covariance matrix and is the weighted multipole average in each bin. The binned power spectrum is then calculated as: .
Inputs[edit]
UPDATE COMMANDER
- Low-l spectrum ( )
- frequency maps from 30–353 GHz
- common mask Planck-2013-XII[1]
- compact sources catalog
- High-l spectrum ( )
- 100, 143, 143x217 and 217 GHz spectra and their covariance matrix (Sec. 3.3 Planck-2015-A13[3])
- best-fit foreground templates and inter-frequency calibration factors (Table 3 of Planck-2015-A13[3])
- Beam transfer function uncertainties Planck-2015-A07[5]
File names and Meta data[edit]
The CMB spectrum and its covariance matrix are distributed in a single FITS file named
which contains 5 extensions
- LOW-ELL (BINTABLE)
- with the low ell part of the spectrum, not binned, and for l=2-49. The table columns are
- ELL (integer): multipole number
- D_ELL (float): $D_l$ as described below
- ERRUP (float): the upward uncertainty
- ERRDOWN (float): the downward uncertainty
- HIGH-ELL (BINTABLE)
- with the high-ell part of the spectrum, binned into 83 bins covering in bins of width (with the exception of the last bin that is smaller). The table columns are as follows:
- ELL (integer): mean multipole number of bin
- L_MIN (integer): lowest multipole of bin
- L_MAX (integer): highest multipole of bin
- D_ELL (float): $D_l$ as described below
- ERR (float): the uncertainty
- COV-MAT (IMAGE)
- with the covariance matrix of the high-ell part of the spectrum in a 83x83 pixel image, i.e., covering the same bins as the HIGH-ELL table.
- HIGH-ELL (BINTABLE)
- with the high-ell part of the spectrum, unbinned, in 2979 bins covering . The table columns are as follows:
- ELL (integer): multipole
- D_ELL (float): $D_l$ as described below
- ERR (float): the uncertainty
- COV-MAT (IMAGE)
- with the covariance matrix of the high-ell part of the spectrum in a 2979x2979 pixel image, i.e., covering the same bins as the HIGH-ELL table.
The spectra give $D_\ell = \ell(\ell+1)C_\ell / 2\pi$ in units of $\mu\, K^2$, and the covariance matrix is in units of $\mu\, K^4$.
The CMB spectrum is also given in a simple text comma-separated file:
Likelihood[edit]
TO BE WRITTEN.
References[edit]
- ↑ 1.01.11.2 Planck 2013 results. XI. Component separation, Planck Collaboration, 2014, A&A, 571, A11
- ↑ 2.02.12.2 Planck 2015 results. XI. CMB power spectra, likelihoods, and robustness of cosmological parameters, Planck Collaboration, 2016, A&A, 594, A11.
- ↑ 3.03.13.23.33.4 Planck 2015 results. XIII. Cosmological parameters, Planck Collaboration, 2016, A&A, 594, A13.
- ↑ 4.04.1 Planck 2013 results. XV. CMB power spectra and likelihood, Planck Collaboration, 2014, A&A, 571, A15
- ↑ Planck 2015 results. VII. High Frequency Instrument data processing: Time-ordered information and beam processing, Planck Collaboration, 2016, A&A, 594, A7.
Cosmic Microwave background
Flexible Image Transfer Specification