lfkit.corrections.color_anchors#
Color-anchor utilities for kcorrect.
- Core concept:
An “anchor” is defined by a single two-band color constraint:
color = (band_a - band_b) = color_value
where band_a and band_b are kcorrect response names (e.g. “sdss_g0”).
This module is intentionally agnostic: - no galaxy “types” - no “red/blue” naming - no survey assumptions beyond optional filter mapping wrappers
- What this module does:
The goal is simply to obtain a set of kcorrect template coefficients that reproduce a specified two-band color at a given redshift. Since a color only fixes a flux ratio, the overall normalization of the SED is arbitrary. To make the problem well defined we choose an arbitrary reference magnitude (“anchor”) and construct a minimal synthetic photometry vector consistent with the requested color. Those fluxes are then passed to kcorrect to solve for the template mixture.
- Important limitations:
The resulting coefficients are not a unique physical SED fit. A single color constraint leaves large degeneracies in template space. The anchor normalization is purely a gauge choice, and no attempt is made to infer galaxy type, stellar population parameters, dust, or luminosity evolution. The coefficients are therefore best interpreted as a convenient internal representation for evaluating K(z) curves consistent with the specified color constraint.
Functions
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Fit kcorrect coefficients from a single two-band color constraint. |