Description
Calculate a supplied Hubble-parameter magnitude offset relative to a reference.
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 Hubble-parameter magnitude offset relative to a reference.
When to use this tool
Use Magnitude Hubble Parameter Offset when you already have hValue, referenceH and need to calculate a supplied Hubble-parameter magnitude offset relative to a reference.
How to use the tool and how it works
- Enter hValue, referenceH. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read magnitudeOffset. Use the output convention below.
Require hValue/referenceH positive/finite; return -5*(log10(hValue)-log10(referenceH)).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| hValue | H Value | Required. Finite number; strictly above 0. |
| referenceH | Reference H | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| magnitudeOffset | -5*(log10(hValue)-log10(referenceH)); both h values are positive and dimensionless. | Required. Finite number. |
{
"input": {
"hValue": 1,
"referenceH": 0.1
},
"output": {
"magnitudeOffset": -5
}
}Limitations and assumptions
- Both h values are dimensionless on the same convention. The sign follows this chosen offset; no Hubble constant, candle calibration or absolute magnitude 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
- Standard Candle Distance Modulus Residual
Compare supplied distance moduli and calculate their model-relative distance ratio.
- Cosmological H Scaled Mass Crosswalk
Apply a supplied h exponent to a quoted cosmological mass.