AA  Semi-analytic Model of Galaxy Formation

 

 

The model consists of three steps, each implemented by a different numerical code. The model steps and the corresponding numerical codes are summarized in the table below. Follow the links to access the pages concerning a given step.

 

 

 

MODEL STEP

NUMERICAL CODE

DESCRIPTION

 

 

 

GENERATION OF DM MERGING TREES

dmtree.f90

 

It generates a given number of Dark Matter merging trees according to the statristics described by the Extended Press & Schechter (EPS) Theory (see, e.g., Lacey & Cole 1993) .

 

GENERATION OF THE MERGING HISTORY OF GALACTIC DM SUB_HALOS

galtree.f90

 

Based on the DM merging trees generated by dmtree.f90, it generates the merging trees of the Dark Matter galactic sub-clumps; these are constituted by the DM haloes which, once included into a larger halo, survive in the new halo until their orbits decay to the center due to dynamical friction (thus coalescing with the central dominant galaxy of the host halo) or they merge with another sub-clump due to collisons in the common DM host halo.

 

COMPUTION OF THE BARYONIC PROCESSES WITHIN DM HALOES AND THE ASSOCIATED EMISSION

 

galev.f90

 

Based on the merging trees of galactic clumps generated by galtree.f90, it computes the properties of the galaxies associated to the DM sub-clumps, by implementing the usual prescriptions adopted by SAMs, and the corresponding emission due to the evolving stellar populations contained in the galaxies. As an output, such a program yields a synthetic catalog containg, for each galaxy, the gas mass, the stellar mass, and the magnitudes (in the usual photometric bands) .

 

 

 

Unless otherwise specified, the physical units are set as follows throughout the model:


1) The mass is in units of 1012 Mʘ

2) The velocity is in units of 100 km/s

3) The time is in units of 1/H0