lfkit.photometry.magnitudes module#

Magnitude conversion utilities for LFKit.

This module provides helpers to translate between apparent m and absolute magnitudes M using the cosmology utilities defined in LFKit.

The conversions follow the convention

M = m - mu - K + E m = M + mu + K - E

where mu is the distance modulus, K is the k-correction, and E is the evolution correction.

All returned quantities are NumPy arrays of dtype float.

lfkit.photometry.magnitudes.absolute_magnitude(cosmo_obj, z, apparent_mag, *, h=None, k_correction=None, e_correction=None)[source]#

Convert apparent magnitude m to absolute magnitude M.

The convention used is

M = m - mu - K + E.

Parameters:

  • cosmo_obj (Any) – Cosmology object passed to LFKit distance utilities.

  • z (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Redshift value or array-like of redshift values.

  • apparent_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Apparent magnitude value(s).

  • h (float | None) – Optional dimensionless Hubble parameter. If provided, the distance modulus uses mu = 5 log10(d_L * h) + 25.

  • k_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional k-correction term(s).

  • e_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional evolution-correction term(s).

Returns:

NumPy array of absolute magnitudes.

Return type:

ndarray[tuple[Any, …], dtype[float64]]

lfkit.photometry.magnitudes.absolute_magnitude_from_luminosity_distance(apparent_mag, luminosity_distance_mpc, *, k_correction=None, e_correction=None)[source]#

Convert apparent magnitude to absolute magnitude from luminosity distance.

The convention used is

M = m - mu - K + E,

with

mu = 5 log10(d_L / Mpc) + 25.

Parameters:

  • apparent_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Apparent magnitude value(s).

  • luminosity_distance_mpc (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Luminosity distance value(s) in Mpc.

  • k_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional k-correction term(s).

  • e_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional evolution-correction term(s).

Returns:

NumPy array of absolute magnitudes.

Return type:

ndarray[tuple[Any, …], dtype[float64]]

lfkit.photometry.magnitudes.apparent_magnitude(cosmo_obj, z, absolute_mag, *, h=None, k_correction=None, e_correction=None)[source]#

Convert absolute magnitude M to apparent magnitude m.

The convention used is

m = M + mu + K - E.

Parameters:

  • cosmo_obj (Any) – Cosmology object passed to LFKit distance utilities.

  • z (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Redshift value or array-like of redshift values.

  • absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute magnitude value(s).

  • h (float | None) – Optional dimensionless Hubble parameter. If provided, the distance modulus uses mu = 5 log10(d_L * h) + 25.

  • k_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional k-correction term(s).

  • e_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional evolution-correction term(s).

Returns:

NumPy array of apparent magnitudes.

Return type:

ndarray[tuple[Any, …], dtype[float64]]

lfkit.photometry.magnitudes.apparent_magnitude_from_luminosity_distance(absolute_mag, luminosity_distance_mpc, *, k_correction=None, e_correction=None)[source]#

Convert absolute magnitude to apparent magnitude from luminosity distance.

The convention used is

m = M + mu + K - E,

with

mu = 5 log10(d_L / Mpc) + 25.

Parameters:

  • absolute_mag (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute magnitude value(s).

  • luminosity_distance_mpc (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]]) – Luminosity distance value(s) in Mpc.

  • k_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional k-correction term(s).

  • e_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional evolution-correction term(s).

Returns:

NumPy array of apparent magnitudes.

Return type:

ndarray[tuple[Any, …], dtype[float64]]

lfkit.photometry.magnitudes.total_magnitude_correction(*, k_correction=None, e_correction=None)[source]#

Return the net correction added to apparent absolute conversion.

This combines optional k-correction and evolution-correction terms as

correction = K - E

so that

M = m - mu - correction.

Parameters:

  • k_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional k-correction term(s).

  • e_correction (float | Sequence[float] | ndarray[tuple[Any, ...], dtype[float64]] | None) – Optional evolution-correction term(s).

Returns:

NumPy array of net correction values.

Return type:

ndarray[tuple[Any, …], dtype[float64]]