Disclaimer: This code is distributed freely to the community. The user accepts
sole responsibility for the results produced by the code. Although every effort
has been made to identify and eliminate errors, we accept no responsibility
for erroneous model predictions.
The code and the models should be referenced as Leitherer et al. (1999).
Download the source code
The package comes with quite a few files. Some are essential whereas others are not, and you can do without them.
How to run the code
Get organized first.
Once all the files are in place and the declarations are complete, the input parameters need to be specified. If this is your first attempt, we suggest to leave the parameters as they are. They produce reasonable results and should give you a first impression of what is in store. Once you have gained more experience and have become more adventurous, you can modify the parameters to suit your needs. These are the parameters to play with:
MODEL DESIGNATION: [NAME] z=10 galaxy --- any identifier you want to assign to the model. You will find it in the header of each output file.
CONTINUOUS STAR FORMATION (>0) OR FIXED MASS (<=0): [ISF] -1 -- if this is a negative integer, star formation is instantaneous, otherwise it is continuous.
TOTAL STELLAR MASS [106 SOLAR MASSES] IF 'FIXED MASS' IS CHOSEN: [TOMA] 1. -- this is the total stellar mass (spread out between the upper and lower cut-off mases). It is only used if an instantaneous burst is specified.
SFR [SOLAR MASSES PER YEAR] IF 'CONT. SF' IS CHOSEN: [SFR] 1. -- the star formation rate (only used for a continuous rate). The total accumulated mass is spread out between the upper and lower cut-off mases.
IMF EXPONENT (2.35 = SALPETER): [ALPHA] 2.35 -- IMF exponent. A power law is assumed.
UPPER MASS LIMIT FOR IMF [SOLAR MASSES]: [UPMA] 100. -- upper mass limit for the IMF.
LOWER MASS LIMIT FOR IMF [SOLAR MASSES]: [DOMA] 1. -- lower mass limit for the IMF.
SUPERNOVA CUT-OFF MASS [SOLAR MASSES]: [SNCUT] 8.0 -- stars with ZAMS masses of 8 M and higher form supernovae. This is the suggested standard value but can be modified if desired.
BLACK HOLE CUT-OFF MASS [SOLAR MASSES]: [BHCUT] 120. -- stars with ZAMS masses of 120 M and lower form supernovae. An alternative scenario would be to let stars above a certain threshold form a black hole. For instance, BHCUT=40. results in SNe only from the mass range 40 to 8 M.
METALLICITY + TRACKS: [IZ] 92-94 STD. MASS-LOSS: 11=0.001; 12=0.004; 13=0.008; 14=0.020; 15=0.040 92-94 HIGH MASS-LOSS: 21=0.001; 22=0.004; 23=0.008; 24=0.020; 25=0.040 14 -- this integer indicates the evolutionary tracks to be used.
WIND MODEL (0: MAEDER; 1: EMP.; 2: THEOR.; 3: ELSON): [IWIND] 2 -- this selects the wind model to be used for the calculation of the wind power. The four models are discussed in ApJ, 401, 498 (1992). "2" is the suggested default parameter.
INITIAL TIME [1.E6 YEARS]: [TIME1] 0.01 -- the epoch of the onset of the star formation. In almost all cases you want this to be close to 0. It should not be exactly 0 for numerical reasons. 0.01 (i.e. 10e4 yr) is a good number.
TIME STEP [1.e6 YEARS]: [STEP] 0.1 -- this is the timestep used for the calculations. It is a very important parameter. On the one hand, the computing time scales with STEP, so you want to avoid too high resolution, but on the other, short evolutionary phases can be missed. 0.1 (i.e. 10e5 yr) is a good value if you use full isochrone synthesis. If full isochrone synthesis is not used, 0.1 or large is suggested only for tests --- be aware that WR or RSG numbers are no longer properly calculated for a STEP of 0.1 and without full ischrone synthesis!
LAST GRID POINT [1.e6 YEARS]: [TMAX] 20. -- the oldest age of the model.
SMALL (=0) OR LARGE (=1) MASS GRID; ISOCHRONE ON LARGE GRID (=2) OR FULL ISOCHRONE (=3): [JMG] 3 -- these are four options for the interpolation in mass. They are explained in the code. Shortly: 0 -- evolutionary synthesis with a mass resolution of 5 M (only recommended for tests); 1 -- same as 0, but with a resolution of 1 M. This method was used in Leitherer & Heckman (1995); 2 -- isochrone synthesis with a fixed mass resolution of 1 M; 3 -- isochrone synthesis with a variable mass grid. This is the fanciest method and is the recommended mode.
LMIN, LMAX (ALL=0): [LMIN,LMAX] 0 -- LMIN and LMAX are the indices of the evolutionary tracks, sorted by mass. Normally you do not want to mess with the variable and leave it at 0. However, if you want to track down some peculiarity of the output, you may want to compute the parameters for only one track. For instance, specifying 21,21 indicates that only a 100 M star should be used, and everything else is suppressed. The cross-ID's between index and mass are at the bottom of the input file. The example here refers to JMG=1 or 2. For JMG=0, you would have chosen 5,5. This does not apply to JMG=3 since the mass grid is variable. If JMG=3, LMIN and LMAX are not used.
TIME STEP TO PRINT OUT THE SYNTH.SPECTRUM AND LINE [1.e6YR]: [TDEL] 1.0 -- the file containing the output spectrum can be pretty big. This parameter controls the time step to print out the spectrum. This is independent of the time resolution -- only the print out is affected! 1 Myr is usually a good value but if you compute the starburst up to 100 Myr, you may prefer TDEL=5 Myr unless you have many Mb of disk space.
ATMOSPHERE FOR SYNTHETIC SPECTRUM: 1=MAX, 2=BOB, 3=WERNER [IATMOS] 3 -- this is the choice of the model atmosphere. 1 is a bare-bone version with black bodies, good only for tests. 2 uses the Kurucz models as compiled by Lejeune for all stars. 3 uses Lejeune for stars with plane-parallel atmospheres and Schmutz for stars with strong winds. 3 is the recommended value.
METALLICITY OF THE UV LINE SPECTRUM: (1=SOLAR, 2=LMC/SMC) [ILINE] 1 -- a switch for the choice of the UV spectral library. This is independent of the metallicity of the tracks/atmospheres. Normally one would use ILINE=1 with IZ=14/24 and ILINE=2 with IZ=12/22.
RSG FEATURE: MICROTURB. VEL (1-6), SOL/NON-SOL ABUND (0,1) [IVT,IRSG] 3,0 -- atmospheric parameters used for the spectral features in the near-IR. Detailed explanations are in the sp-feature subroutine. Defaults are 3,0, i.e. microturbulent velocities of 3 km/sec and solar abundance ratios for alpha-element/Fe
OUTPUT FILES (NO<0, YES>=0) [IO1,...] +1,+1,+1,+1,+1,+1,+1,+1,+1,+1,+1,+1,+1,+1 These are options to generate various outputs. We recommend to set all flags to "yes", at least until you become more familiar with the code. Some of the subroutines are interrelated. If you choose such a subroutine but not the other, required one, a warning will be issued. The 14 output flags are explained in the next section.