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CMB Bandpower Ell Weight

Calculate D_l=l(l+1)C_l/(2 pi) from an explicit multipole and supplied C_l without beam, mask or noise correction.

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Description

Apply the supplied multipole weighting to an angular-power value.

Cosmological quantities depend on scale factor, redshift, distance definition and the dimensionless Hubble parameter h. Proper and comoving distances differ at a specified epoch, and h-scaled units differ from the dimensional Hubble constant. A scalar rescaling or model contribution preserves supplied conventions without fitting a cosmology or inferring an observed distance.

Apply the supplied multipole weighting to an angular-power value.

When to use this tool

Use CMB Bandpower Ell Weight when you already have multipole, angularPower and need to apply the supplied multipole weighting to an angular-power value.

How to use the tool and how it works

  1. Enter multipole, angularPower. Use the units and conventions below.
  2. Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
  3. Read weightedBandpower. Use the output convention below.

Require multipole a nonnegative safe integer; return ell*(ell+1)/(2π)*angularPower.1

Input fieldMeaning and unitsAccepted input
multipoleMultipoleRequired. Safe integer; minimum 0.
angularPowerAngular PowerRequired. Finite number.
Output fieldInterpretationReturned shape
weightedBandpowermultipole*(multipole+1)*angularPower/(2π); a local D_l-style weighting, without bin averaging or spectral-density normalization.Required. Finite number.
json
{
  "input": {
    "multipole": 2,
    "angularPower": 3
  },
  "output": {
    "weightedBandpower": 2.864788975654116
  }
}

Limitations and assumptions

  • The amplitude unit follows angularPower and values may be signed. This is one convention transformation, not a measured spectrum, bin average, sky analysis or cosmological fit; large multipoles lose integer precision in intermediate products.
  • Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
  • Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Use the complete cosmological model and its parameter, epoch and unit definitions for a physical inference. Review redshift, distance, lensing and spectrum conventions before combining these local terms; they do not perform line-of-sight integration, parameter estimation or uncertainty analysis.

References

  1. Calculation and input contract: cosmology/cmb-bandpower-ell-weight — tool.io

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