/** @brief Main recipe, calculates the fraction of cold gas turned into stars due
* to star formation; the fraction of mass instantaneously recycled and
* returned to the cold gas; the fraction of gas reheated from cold to hot,
* ejected from hot to external and returned from ejected to hot due to
* SN feedback. */
void starformation(int p, int centralgal, double time, double dt, int nstep)
{
/*! Variables: reff-Rdisk, tdyn=Rdisk/Vmax, strdot=Mstar_dot, stars=strdot*dt*/
double tdyn, strdot=0., stars, cold_crit, metallicitySF;
if(Gal[p].Type == 0)
{
tdyn = Gal[p].GasDiskRadius / Gal[p].Vmax;
cold_crit = SfrColdCrit * Gal[p].Vmax/200. * Gal[p].GasDiskRadius*100.;
}
else
{
tdyn = Gal[p].GasDiskRadius / Gal[p].InfallVmax;
cold_crit = SfrColdCrit * Gal[p].InfallVmax/200. * Gal[p].GasDiskRadius*100.;
}
//standard star formation law (Croton2006, Delucia2007, Guo2010)
if(StarFormationModel == 0)
{
if(Gal[p].ColdGas > cold_crit)
strdot = SfrEfficiency * (Gal[p].ColdGas - cold_crit) / tdyn;
else
strdot = 0.0;
}
/*if(StarFormationModel == 1)
{
strdot = ALTERNATIVE STAR FORMATION LAW
}*/
/* Note that Units of dynamical time are Mpc/Km/s - no conversion on dt needed */
stars = strdot * dt;
if(stars < 0.0)
terminate("***error stars<0.0***\n");
//otherwise cold gas and stars share material in update_stars_due_to_reheat
#ifdef FEEDBACK_COUPLED_WITH_MASS_RETURN
if(stars > Gal[p].ColdGas)
stars = Gal[p].ColdGas;
#endif
mass_checks("recipe_starform #1",p);
mass_checks("recipe_starform #1.1",centralgal);
/* update for star formation
* updates Mcold, StellarMass, MetalsMcold and MetalsStellarMass
* in Guo2010 case updates the stellar spin -> hardwired, not an option */
/* Store the value of the metallicity of the cold phase when SF occurs */
if (Gal[p].ColdGas > 0.)
metallicitySF= metals_total(Gal[p].MetalsColdGas)/Gal[p].ColdGas;
else
metallicitySF=0.;
if (stars > 0.)
update_stars_due_to_reheat(p, centralgal, &stars);
mass_checks("recipe_starform #2",p);
mass_checks("recipe_starform #2.1",centralgal);
/* update the star formation rate */
/*Sfr=stars/(dt*steps)=strdot*dt/(dt*steps)=strdot/steps -> average over the STEPS*/
Gal[p].Sfr += stars / (dt * STEPS);
// update_from_star_formation can only be called
// after SD_feeedback recipe since stars need to be re_set once the reheated mass is known
// (star formation and feedback share the same fraction of cold gas)
if (stars > 0.)
update_from_star_formation(p, stars, false, nstep); // false indicates not a burst
update_massweightage(p, stars, time);
#ifndef FEEDBACK_COUPLED_WITH_MASS_RETURN
/* ifdef FEEDBACK_COUPLED_WITH_MASS_RETURN feedback is only called
* when stars die, inside DETAILED_METALS_AND_MASS_RETURN */
if (stars > 0.)
SN_feedback(p, centralgal, stars, "ColdGas");
#endif
#ifdef COMPUTE_SPECPHOT_PROPERTIES
#ifndef POST_PROCESS_MAGS
/* Update the luminosities due to the stars formed */
if (stars > 0.0)
add_to_luminosities(p, stars, time, dt, metallicitySF);
#endif //NDEF POST_PROCESS_MAGS
#endif //COMPUTE_SPECPHOT_PROPERTIES
if(Gal[p].DiskMass > 0.0)
check_disk_instability(p);
if (DiskRadiusModel== 0)
get_stellar_disk_radius(p);
}
void deal_with_galaxy_merger(int p, int merger_centralgal, int centralgal, double time, double deltaT, int nstep)
{
/** @brief Deals with the physics triggered by mergers, according to the mass
* fraction of the merger \f$(M_{\rm{sat}}/M_{\rm{central}}><0.3)\f$.
* Add the cold and stellar phase of the satellite galaxy to the central
* one, form a bulge at the central galaxy with the stars from the
* satellite in a minor merger if BulgeFormationInMinorMergersOn=1.
* Grows black hole through accretion from cold gas "quasar mode".
* If StarBurstRecipe = 0, the Somerville 2001 model
* of bursts is used, SN Feedback from starformation is computed and
* the sizes of bulge and disk followed. When a major merger occurs,
* the disk of both merging galaxies is completely destroyed to form
* a bulge. */
double mi, ma, mass_ratio, Mcstar, Mcgas, Mcbulge, Mpstar, Mpgas,Mpbulge;
double frac;
#ifdef GALAXYTREE
int q;
mass_checks("deal_with_galaxy_merger #0",p);
mass_checks("deal_with_galaxy_merger #0",merger_centralgal);
mass_checks("deal_with_galaxy_merger #0",centralgal);
q = Gal[merger_centralgal].FirstProgGal;
if(q >= 0)
{
while(GalTree[q].NextProgGal >= 0)
q = GalTree[q].NextProgGal;
GalTree[q].NextProgGal = Gal[p].FirstProgGal;
if(GalTree[q].NextProgGal >= NGalTree)
{
printf("q=%d p=%d GalTree[q].NextProgGal=%d NGalTree=%d\n",
q, p, GalTree[q].NextProgGal, NGalTree);
terminate("problem");
}
}
if(q < 0)
terminate("may not happen");
q = GalTree[q].NextProgGal;
if(HaloGal[GalTree[q].HaloGalIndex].GalTreeIndex != q)
terminate("inconsistency");
HaloGal[GalTree[q].HaloGalIndex].MergeOn = 2;
if(Gal[p].Type == 1)
HaloGal[GalTree[q].HaloGalIndex].MergeOn = 3;
#endif
/* flag galaxy as finished */
Gal[p].Type = 3;
/* calculate mass ratio of merging galaxies */
mi = Gal[p].DiskMass+Gal[p].BulgeMass+Gal[p].ColdGas;
ma = Gal[merger_centralgal].DiskMass+Gal[merger_centralgal].BulgeMass+Gal[merger_centralgal].ColdGas;
if(max(mi,ma) > 0.)
mass_ratio = min(mi,ma) / max(mi,ma);
else
mass_ratio = 1.0;
/* record the gas and stellar component mass of merger central and satellite
* galaxies before the before merger */
Mcstar=(Gal[merger_centralgal].DiskMass+Gal[merger_centralgal].BulgeMass);
Mcbulge=Gal[merger_centralgal].BulgeMass;
Mcgas=Gal[merger_centralgal].ColdGas;
Mpstar=(Gal[p].DiskMass+Gal[p].BulgeMass);
Mpbulge=Gal[p].BulgeMass;
Mpgas=Gal[p].ColdGas;
mass_checks("deal_with_galaxy_merger #1",p);
mass_checks("deal_with_galaxy_merger #1",merger_centralgal);
mass_checks("deal_with_galaxy_merger #1",centralgal);
/* Add the cold and stellar phase of the merged galaxy to the central one.
Also form a bulge if BulgeFormationInMinorMergersOn is set on, but only
with the stars from the satellite. In a major merger (dealt at the burst
make_bulge_from_burst) all the stars in the central and satellite end up
in the central bulge. */
add_galaxies_together(merger_centralgal, p);
mass_checks("deal_with_galaxy_merger #2",p);
mass_checks("deal_with_galaxy_merger #2",merger_centralgal);
mass_checks("deal_with_galaxy_merger #2",centralgal);
/* grow black hole through accretion from cold disk during mergers, as in
* Kauffmann & Haehnelt (2000) + minor mergers - Quasar Mode */
if(AGNrecipeOn > 0)
grow_black_hole(merger_centralgal, mass_ratio, deltaT);
mass_checks("deal_with_galaxy_merger #3",p);
mass_checks("deal_with_galaxy_merger #3",merger_centralgal);
mass_checks("deal_with_galaxy_merger #3",centralgal);
if (StarBurstRecipe == 0) {
/* Starburst as in Somerville 2001, with feedback computed inside. */
frac=collisional_starburst_recipe(mass_ratio, merger_centralgal, centralgal, time, deltaT, nstep);
bulgesize_from_merger(mass_ratio,merger_centralgal,p,Mcstar,Mcbulge,Mcgas,
Mpstar,Mpbulge,Mpgas,frac);
mass_checks("deal_with_galaxy_merger #3.5",p);
mass_checks("deal_with_galaxy_merger #3.5",merger_centralgal);
mass_checks("deal_with_galaxy_merger #3.5",centralgal);
if(mass_ratio > ThreshMajorMerger)
make_bulge_from_burst(merger_centralgal);
}
mass_checks("deal_with_galaxy_merger #4",p);
mass_checks("deal_with_galaxy_merger #4",merger_centralgal);
mass_checks("deal_with_galaxy_merger #4",centralgal);
/* If we are in the presence of a minor merger, check disk stability (the disk
* is completely destroyed in major mergers)*/
if(TrackDiskInstability)
if(mass_ratio < ThreshMajorMerger &&
(Gal[merger_centralgal].DiskMass+Gal[merger_centralgal].BulgeMass) > 0.0)
check_disk_instability(merger_centralgal);
/* Not supported option to shrink bulge sizes in gas rich mergers */
#ifdef SHRINKINRICHMERGER
if (Mcgas+Mcstar+Mpgas+Mpstar > 1.e-8 ) {
Gal[merger_centralgal].BulgeSize /= 1+pow((Mcgas+Mpgas)/(Mcgas+Mcstar+Mpgas+Mpstar)/0.15,1.);
if (Gal[merger_centralgal].BulgeSize < 1.e-8)
Gal[merger_centralgal].BulgeSize = 1.e-8;
}
#endif
if ((Gal[merger_centralgal].BulgeMass > 1.e-6 && Gal[merger_centralgal].BulgeSize == 0.0) ||
(Gal[merger_centralgal].BulgeMass == 0.0 && Gal[merger_centralgal].BulgeSize >1.e-6)) {
printf("central: stellarmass %f, bulgemass %f, bulgesize %f, coldgas %f,gasdisk %f,stellardisk %f \n",
(Gal[merger_centralgal].DiskMass+Gal[merger_centralgal].BulgeMass),Gal[merger_centralgal].BulgeMass,
Gal[merger_centralgal].BulgeSize,Gal[merger_centralgal].ColdGas,Gal[merger_centralgal].GasDiskRadius,
Gal[merger_centralgal].StellarDiskRadius);
exit(0);
}
if (DiskRadiusMethod == 2) {
get_gas_disk_radius(merger_centralgal);
get_stellar_disk_radius(merger_centralgal);
}
mass_checks("deal_with_galaxy_merger #5",p);
mass_checks("deal_with_galaxy_merger #5",merger_centralgal);
mass_checks("deal_with_galaxy_merger #5",centralgal);
}
//void update_from_star_formation(int p, double time, double stars, double metallicity)
void update_from_star_formation(int p, double stars, bool flag_burst, int nstep)
{
int i;
double fraction;
double stars_to_add=0.;
if(Gal[p].ColdGas <= 0. || stars <= 0.) {
printf("update_from_star_formation: Gal[p].ColdGas <= 0. || stars <= 0.\n");
exit(0);
}
/* If DETAILED_METALS_AND_MASS_RETURN, no longer an assumed instantaneous
* recycled fraction. Mass is returned over time via SNe and AGB winds.
* Update the Stellar Spin when forming stars */
#ifndef DETAILED_METALS_AND_MASS_RETURN
stars_to_add=(1 - RecycleFraction) * stars;
#else
stars_to_add=stars;
#endif
if (Gal[p].DiskMass+stars_to_add > 1.e-8)
for (i = 0; i < 3; i++)
Gal[p].StellarSpin[i]=((Gal[p].StellarSpin[i])*(Gal[p].DiskMass) + stars_to_add*Gal[p].GasSpin[i])/(Gal[p].DiskMass+stars_to_add);
/* Update Gas and Metals from star formation */
mass_checks("update_from_star_formation #0",p);
fraction=stars_to_add/Gal[p].ColdGas;
#ifdef STAR_FORMATION_HISTORY
Gal[p].sfh_DiskMass[Gal[p].sfh_ibin]+=stars_to_add; //ROB: Now, all SF gas is put in SFH array ("recycled' mass will return to gas phase over time)
Gal[p].sfh_MetalsDiskMass[Gal[p].sfh_ibin] = metals_add(Gal[p].sfh_MetalsDiskMass[Gal[p].sfh_ibin],Gal[p].MetalsColdGas,fraction);
#ifdef INDIVIDUAL_ELEMENTS
Gal[p].sfh_ElementsDiskMass[Gal[p].sfh_ibin] = elements_add(Gal[p].sfh_ElementsDiskMass[Gal[p].sfh_ibin],Gal[p].ColdGas_elements,fraction);
#endif
#ifdef TRACK_BURST
if (flag_burst) Gal[p].sfh_BurstMass[Gal[p].sfh_ibin]+=stars_to_add;
#endif
#endif
Gal[p].MetalsDiskMass=metals_add(Gal[p].MetalsDiskMass,Gal[p].MetalsColdGas,fraction);
Gal[p].MetalsColdGas=metals_add(Gal[p].MetalsColdGas,Gal[p].MetalsColdGas,-fraction);
//GLOBAL PROPERTIES
Gal[p].DiskMass += stars_to_add;
Gal[p].ColdGas -= stars_to_add;
#ifdef INDIVIDUAL_ELEMENTS
Gal[p].DiskMass_elements=elements_add(Gal[p].DiskMass_elements,Gal[p].ColdGas_elements,fraction);
Gal[p].ColdGas_elements=elements_add(Gal[p].ColdGas_elements,Gal[p].ColdGas_elements,-fraction);
#endif
#ifdef TRACK_BURST
if (flag_burst) Gal[p].BurstMass+=stars_to_add;
#endif
mass_checks("update_from_star_formation #1",p);
/* Formation of new metals - instantaneous recycling approximation - only SNII
* Also recompute the metallicity of the cold phase.*/
#ifndef DETAILED_METALS_AND_MASS_RETURN
/* stars used because the Yield is defined as a fraction of
* all stars formed, not just long lived */
Gal[p].MetalsColdGas += Yield * stars;
#endif
if (DiskRadiusModel == 0)
get_stellar_disk_radius(p);
}