Description
Return a supplied observed width on a rest-frame basis.
Survey geometry combines solid angle, radial distance and a stated coordinate or selection basis. A sky fraction, bin midpoint or thin-shell term is a local geometric quantity rather than an integrated survey volume, observed population or selection-corrected estimate.
Return a supplied observed width on a rest-frame basis.
When to use this tool
Use Galaxy Redshift Bin Rest Frame Width when checking the stated survey-area, bin or comoving-volume term.
How to use the tool and how it works
- Enter centerRedshift, observedWidth. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read restFrameWidth. Use the output convention below.
Return a supplied observed width on a rest-frame basis. Require centerRedshift > -1 and observedWidth >= 0; restFrameWidth = observedWidth/(1+centerRedshift).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| centerRedshift | Center Redshift | Required. Finite number; strictly above -1. |
| observedWidth | Observed Width | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| restFrameWidth | Rest Frame Width | Required. Finite number. |
{
"input": {
"centerRedshift": 1,
"observedWidth": 0.2
},
"output": {
"restFrameWidth": 0.1
}
}Limitations and assumptions
- This is a local width scaling with one central redshift, not a full bin transformation or a cosmological distance conversion.
- 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
Integrate the appropriate cosmological volume element and actual survey mask/selection function for complete coverage or number-count analysis.
References
Similar or alternative tools
- Redshift Bin Center Shift
Return the midpoint of a supplied redshift bin and its reference shift.
- Cosmological Time Dilation Interval Pair
Apply cosmological observed-to-rest interval factor 1+z using an explicit redshift greater than minus one.