For code version >= 2.2.0

Go here for an older versions of this usage page for code version 2.0 (first SALT2 release)

Complete installation scripts

Recommended if you are not familiar with the package organization and want to reproduce published results.

Download one of the following scripts in the directory where you want to install the package and execute it (you need to do a chmod u+x first, you also need to have wget installed).

You can check the agreement of the content of the output file result_salt2.dat with the released result for the SN in the test directory result_salt2_xxx.dat.

Setup of model data

  1. Create a directory (DIR) for the model data and set an environement variable SALTPATH (or PATHMODEL for versions < 2…) pointing to it. The code will look for a file fitmodel.card in this directory.
  2. Download some instruments (here) and save them in the DIR directory. Edit DIR/fitmodel.card to point to the instruments. The key name has to match the one in the lightcurve.
  3. Download magnitude systems (here) and save them in the DIR directory. Edit DIR/fitmodel.card to point to the current file describing the magnitude system (go there for more details about magnitude systems). The key name has to match the one in the lightcurve.
  4. Download SALT2 (or/and SALT1) templates (here), save them in the DIR directory, and edit DIR/fitmodel.card.




4Shooter2  Bessel                Keplercam        NICMOS2  Sdss2.5
ACSWF      Bessel-shifted-sifto  MegacamVariable  SWIFT    Swope

Vega0.dat                alpha_lyr_stis_004.ascii
VegaBD17-2008-11-28.dat  bd_17d4708_stisnic_002.ascii

salt2_color_correction.dat           salt2_spec_covariance_01.dat
salt2_color_dispersion.dat           salt2_spec_variance_0.dat
salt2_lc_dispersion_scaling.dat      salt2_spec_variance_1.dat
salt2_lc_relative_covariance_01.dat  salt2_template_0.dat
salt2_lc_relative_variance_0.dat     salt2_template_1.dat

more $PATHMODEL/fitmodel.card

@STANDARD  Instruments/Bessel-shifted-sifto
@MEGACAM   Instruments/MegacamVariable
@KEPLERCAM Instruments/Keplercam
@4SHOOTER2 Instruments/4Shooter2
@ACSWF     Instruments/ACSWF
@NICMOS2   Instruments/NICMOS2
@SWIFT     Instruments/SWIFT
@SDSS      Instruments/Sdss2.5
@SWOPE     Instruments/Swope
@VEGA      MagSys/VegaBD17-2008-11-28.dat
@VEGAHST   MagSys/Vega0.dat
@VEGA0     MagSys/Vega0.dat
@SALT2     salt2-2-0

Compilation and installation of the code

tar zxvf snfit_src-[version].tar.gz
cd snfit
configure --prefix=[where_you_want] --enable-static=false
make install

Version 2.2.2 tested successfully on :

  • Unordered List ItemLinux gcc/gfortran 4.1.2,4.2.4,4.4.1, arch: i686,x86_64
  • Mac OS 10.5.8 Intel Core 2 Duo (with gfortran from here )

New: Go here for an easy installation on Mac OS X using the Homebrew package manager. This installation method is maintained by Rui Pereira. Successful Homebrew installation on :

  • Intel Core 2 Duo with Mac OS 10.7.1 (Lion)
  • Intel Core 2 Duo with Mac OS 10.6.8 (Snow Leopard)

Rui : 'For compilation on my Mac (and hence on the homebrew formula) I had to force $LDFLAGS with “-L/path/to/libgfortran -lgfortran”'

Light curves Input format

New light curve format

Since snfit version 2.3, two light curve formats are now available. New light curve format (for snfit version >=2.3.0) a single light curve file for all pass bands (+ optionally a covariance matrix)

Example lc-03D4ag.list:

# light curves from SNLS 3 year analysis
@SN 03D4ag
@Z_HELIO 0.285
@MWEBV 0.0258
@X_FOCAL_PLANE 4.65855
@Y_FOCAL_PLANE -0.130529
@DayMax 52830.921 0.13672582
@COVMAT covmat_lc-03D4ag.dat
@CCD 24
@DEC -17.739655
@RA 333.690959
@z_source H
#Date : 
#Flux : 
#Fluxerr : 
#ZP : 
#Filter : instrument and band
#MagSys : magnitude system
52816.54 87.553312 0.76978898 27.091335 MEGACAM::g VEGA
52824.59 202.89127 0.90009357 27.091335 MEGACAM::g VEGA 
52795.59 -0.18016601 1.1661804 25.913054 MEGACAM::i VEGA
52796.59 0.42716008 1.1578453 25.913054 MEGACAM::i VEGA

There is an additional row with the INSTRUMENT::BAND with respect to the previous format (compare with SNLS-03D4ag/lc2fit_g.dat below). For this particular SNLS example, a covariance matrix covmat_lc-03D4ag.dat identified by the key @COVMAT is expected to be found in the same directory (if there is no @COVMAT key, the errors reported in the file in the row Fluxerr are used, and they are considered as uncorrelated).

"Old" light curve format

lightfile + one lightcurve file per band (+ optionally weight matrices)

Assumed format (if you want to use another one, edit the MeasuredData class) : One directory per supernova containing : - lightfile (ASCII file with redshift, Galactic E(B-V), …) - Several light curve files for each instrument/filter. Example, files :


lightfile :

NAME           1994D
RA             12:34:02.3950
DEC            +07:42:05.700
EPOCH          2000.0
Redshift       0.00266901307822
z_heliocentric 0.001494
z_cmb          0.00266901307822
MWEBV          0.02228

1994D/lc2fit_B.dat :

#Date :
#Mag :
#Magerr :
#end :
49420.900000 14.230000 0.001943
49422.830000 13.290000 0.001175
49423.900000 12.890000 0.000907

(INSTRUMENT name matches entry in fitmodel.card, BAND is one the bands listed in snfit_data/Instruments/Landolt-1/FilterWheel)

There is also a light curve format with fluxes, errors and zero points. Note also that there are now informations about the location of the SN in the focal plane (used in the code for the filter transmission) Example, SNLS-03D4ag/lc2fit_g.dat

@WEIGHTMAT flux_per_night_weightmat_g.dat
#Date :
#Flux :
#Fluxerr :
#ZP :
176.54 10267.351 95.517 32.2024 
185.59 24423.189 102.738 32.2024 
212.53 6733.480 144.903 32.2024 

(Here, an additional file is mentioned : the covariance matrix of the flux measurements) Usage of the light curve fitter The default values for options have changed since version 2.0 (SALT2 first release)!

snfit lightcurve1 lightcurve2 ...
  -o filename              : write output in filename instead of result_salt2.dat
  -m {salt,salt2}          : model (default is salt2)

options for data selection :

  1. r phasemin phasemax : range of phases (default is -15,45)
  2. w wmin wmax : wavelength range (default SALT1:3460,6600 SALT2:3000,7000)
options for model parameters (need to define the model before): 
(for salt : DayMax Dflux Stretch Color Redshift, for salt2 :  DayMax Color X0 X1 Redshift GalaxyType)
  -f name value            : fix the value of parameter 'name'
  -p name mean sigma       : add a gaussian prior for 'name'
  -i name value            : initial value of parameter 'name'
options for assumed uncertainties : 
  -e (0 or 1)              : (diagonal) model uncertainties in chi2 (0=no,1=yes,default=1, for salt2)
  -k (0 or 1)              : k-correction uncertainties in chi2  (0=no,1=yes,default=1,for salt2)
  -U value                 : add observed U-band calibration error (default is 0.1)
  -E  value                : error floor to apply for nearby SNe (frac. of max flux)

The default options are now the one used for the SNLS 3 year analysis: by default SALT2 is used, model uncertainties (diagonal and k-correction uncertainties) are used, the phase range is [-15,+40] days, the wavelength range is [3000,7000] A (central wavelength of the effective filter, rest-frame), a calibration uncertainty of 0.1 is considered for light curve for which the central wavelength of the effective filter is shorter than 4000 A (observer frame) (effectively impacts only U-band observations).

Photometric redshifts and fit of spectroscopic data are not supported in this release.

Other tools

You can write the light curves of the model with snlc (note: you need snfit v 2.4.2 or above to run it with new lightcurve format):

snlc writes an ASCII file with the lightcurve of the model
usage : snlc lightcurve1 lightcurve2 ... -p parameter_filename -o output_filename

parameter_filename is the path of the output file of snfit: (i.e. result_salt.dat or result_salt2.dat)

A simple plotter in python (requires matplotlib and numpy) can be downloaded here If you have a more fancy version of it, please share it. Example :

snfit jla_light_curves/lc-03D4ag.list -o res-03D4ag.txt
snlc jla_light_curves/lc-03D4ag.list -p res-03D4ag.txt -o model-03D4ag.list --data jla_light_curves/lc-03D4ag.list --model model-03D4ag.list --mag

Other implementations of the model and light-curve fitter