ENH: Logistic Completeness function

[philipp128]

Description

This function returns the logistic completeness function:

              1
p(m) = -----------------
       1 + exp{-k(m-m0)}

that describes the probability p(m) that a galaxy of magnitude m is detected in the band.

See also the discussion around eq. (7) and fig. 2 in the ALHAMBRA paper by Lopez-Sanjuan et al. (2017).

Inputs

• apparent magnitudes
• 95% completeness
• 50% completeness

Outputs

• Logistic completeness function

References

• Lopez-Sanjuan et al. 2017