Selection function
Definition: The probability that an object with specified latent and observed properties enters the analyzed sample.
Why it matters here: It is required to answer Which objects never enter the catalog? and to distinguish direct observation from cosmological inference.
Relationships: Read it with Malmquist bias, the model \(p(detected|x) = S(x) p(x) / integral S(x')p(x') dx'\), and the evidence statement The release documentation and published sample counts are cited; no survey completeness map or detection efficiency curve is bundled.
Boundary or common confusion: An observed histogram cannot by itself identify completeness because it mixes cosmological volume, population evolution, and selection.
Malmquist bias
Definition: Preferential inclusion of intrinsically brighter objects in a flux-limited sample.
Why it matters here: It is required to answer Which objects never enter the catalog? and to distinguish direct observation from cosmological inference.
Relationships: Read it with Eddington bias, the model \(p(detected|x) = S(x) p(x) / integral S(x')p(x') dx'\), and the evidence statement The release documentation and published sample counts are cited; no survey completeness map or detection efficiency curve is bundled.
Boundary or common confusion: An observed histogram cannot by itself identify completeness because it mixes cosmological volume, population evolution, and selection.
Eddington bias
Definition: Net migration across a threshold caused by measurement scatter and a steep underlying population distribution.
Why it matters here: It is required to answer Which objects never enter the catalog? and to distinguish direct observation from cosmological inference.
Relationships: Read it with Completeness, the model \(p(detected|x) = S(x) p(x) / integral S(x')p(x') dx'\), and the evidence statement The release documentation and published sample counts are cited; no survey completeness map or detection efficiency curve is bundled.
Boundary or common confusion: An observed histogram cannot by itself identify completeness because it mixes cosmological volume, population evolution, and selection.
Completeness
Definition: The fraction of the target population retained by detection and analysis cuts.
Why it matters here: It is required to answer Which objects never enter the catalog? and to distinguish direct observation from cosmological inference.
Relationships: Read it with Injection-recovery, the model \(p(detected|x) = S(x) p(x) / integral S(x')p(x') dx'\), and the evidence statement The release documentation and published sample counts are cited; no survey completeness map or detection efficiency curve is bundled.
Boundary or common confusion: An observed histogram cannot by itself identify completeness because it mixes cosmological volume, population evolution, and selection.
Injection-recovery
Definition: A calibration procedure that inserts controlled synthetic sources and measures their probability of recovery.
Why it matters here: It is required to answer Which objects never enter the catalog? and to distinguish direct observation from cosmological inference.
Relationships: Read it with Selection function, the model \(p(detected|x) = S(x) p(x) / integral S(x')p(x') dx'\), and the evidence statement The release documentation and published sample counts are cited; no survey completeness map or detection efficiency curve is bundled.
Boundary or common confusion: An observed histogram cannot by itself identify completeness because it mixes cosmological volume, population evolution, and selection.