salt2
SALT2 supernova distance modulus likelihood
File |
supernovae/salt2/salt2_interface.py |
Attribution |
CosmoSIS Team |
|
|
URL |
|
Citations |
https://www.aanda.org/articles/aa/abs/2007/16/aa6930-06/aa6930-06.html |
This module implements a likelihood for Type Ia supernova distance measurements using SALT2 light curve fits. SALT2 is a spectral template method for standardizing supernova luminosities.
The module reads SALT2 fit results including apparent magnitude (mB), color (c), and stretch (x1) parameters along with their covariances, and computes the likelihood comparing predicted distance moduli to the SALT2-derived values.
Assumptions
SALT2 light curve fitting has been performed
Supernova data includes distance modulus and light curve parameters
Setup Parameters
Name |
Type |
Default |
Description |
|---|---|---|---|
dirname |
str |
module directory |
Directory containing SALT2 data files |
filename |
str |
SALT2.FITRES |
Name of SALT2 fit results file |
Input values
Section |
Name |
Type |
Default |
Description |
|---|---|---|---|---|
supernova_params |
alpha |
real |
SALT2 stretch-luminosity parameter |
|
beta |
real |
SALT2 color-luminosity parameter |
||
M |
real |
Absolute B-band magnitude |
||
DeltaM |
real |
Host galaxy mass correction (if used) |
||
distances |
z |
real 1d |
Redshift values for distance calculations |
|
d_l |
real 1d |
Luminosity distance in Mpc |
Output values
Section |
Name |
Type |
Description |
|---|---|---|---|
likelihoods |
salt2_like |
real |
Log-likelihood from SALT2 supernova data |