Description
Return the physical baryon-density parameter combination.
Cosmology uses several distance measures and often expresses the expansion rate in mixed astronomical units. Scale-factor relations, inverse-Hubble scales and relativistic velocity composition answer different questions; units and the distinction between local algebra and an integrated expansion history are essential.
Return the physical baryon-density parameter combination.
When to use this tool
Use Baryon Density Physical Parameter Crosswalk when checking one explicit cosmological distance, redshift-factor or unit convention.
How to use the tool and how it works
- Enter omegaBaryon, h. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read omegaBaryonH2. Use the output convention below.
Return the physical baryon-density parameter combination. Require omegaBaryon >= 0 and h > 0; omegaBaryonH2 = omegaBaryon*h².1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| omegaBaryon | Dimensionless baryon density relative to present critical density. | Required. Finite number; minimum 0. |
| h | H | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| omegaBaryonH2 | Dimensionless omegaBaryon*h², not an SI mass density. | Required. Finite number. |
{
"input": {
"omegaBaryon": 0.05,
"h": 0.7
},
"output": {
"omegaBaryonH2": 0.024499999999999997
}
}Limitations and assumptions
- Both inputs are dimensionless, with h = H0/(100 km s^-1 Mpc^-1); this is not mass density in kg/m³.
- 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 a complete cosmological distance/time calculation and the appropriate observation model when an actual source distance, age or velocity is required.
References
Similar or alternative tools
- Cosmological Wavenumber Hunit Crosswalk
Convert an h-scaled cosmological wavenumber.
- Cosmological Angle Radian Basis Token
Convert a supplied angular value with an explicit radians-per-unit factor.