Description
Calculate a supplied baryon-to-total-matter density-parameter fraction.
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.
Calculate a supplied baryon-to-total-matter density-parameter fraction.
When to use this tool
Use Baryon Fraction Density Parameter Ratio when you already have baryonDensityParameter, matterDensityParameter and need to calculate a supplied baryon-to-total-matter density-parameter fraction.
How to use the tool and how it works
- Enter baryonDensityParameter, matterDensityParameter. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read baryonFraction. Use the output convention below.
Require matterDensityParameter positive/finite and baryon parameter within [0,matter]; return baryon/matter.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| baryonDensityParameter | Baryon Density Parameter | Required. Finite number; minimum 0. |
| matterDensityParameter | Matter Density Parameter | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| baryonFraction | Baryon Fraction | Required. Finite number. |
{
"input": {
"baryonDensityParameter": 0.05,
"matterDensityParameter": 0.25
},
"output": {
"baryonFraction": 0.2
}
}Limitations and assumptions
- Components must use the same critical-density convention and epoch. No density, cosmic abundance, uncertainty or complete matter model is inferred.
- 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
Similar or alternative tools
- Cosmology Density Closure Residual
Calculate a supplied density-parameter sum and target residual.
- Magnitude Hubble Parameter Offset
Calculate a supplied Hubble-parameter magnitude offset relative to a reference.