Bulge mass due to accreted stars is now followed

- Previously, the code was following only the mass that was formed via
starbursts due to disk instabilities and mergers. That mass is by
definition in the bulge. However, another growth channel for the bulge
is the accretion of stars that were formed in the disk of the primary
and/or secondary galaxy that because of the merger is transferred to the
bulge. This is now being followed. 

- For that it was necessary to add in the components.h a property to
track that growth channel, and galaxy_mergers was edited to explicitely
track that growth.

include/components.h

@@ -191,6 +191,7 @@ class Galaxy : public Identifiable<int> {
 	Baryon disk_gas {};
 	Baryon galaxymergers_burst_stars {};
 	Baryon diskinstabilities_burst_stars {};
+	Baryon galaxymergers_assembly_stars {};
 	BlackHole smbh {};
 
 	//save average star formation rates and metallicities of the newly formed stars.

src/galaxy_mergers.cpp

@@ -383,6 +383,10 @@ void GalaxyMergers::create_merger(GalaxyPtr &central, GalaxyPtr &satellite, Halo
 	//satellite stellar mass is always transferred to the bulge.
 	transfer_history_satellite_to_bulge(central, satellite, snapshot);
 
+	//transfer mass that was created in starbursts/disk instabilities.
+	central->galaxymergers_burst_stars += satellite->galaxymergers_burst_stars;
+	central->diskinstabilities_burst_stars += satellite->diskinstabilities_burst_stars;
+
 	/**
 	 * Depending on the mass ratio, the baryonic components of the satellite and the disk of the major galaxy are going to be transferred differently.
 	 */
@@ -396,6 +400,11 @@ void GalaxyMergers::create_merger(GalaxyPtr &central, GalaxyPtr &satellite, Halo
 
 		central->bulge_stars.mass += central->disk_stars.mass + satellite->stellar_mass();
 		central->bulge_stars.mass_metals += central->disk_stars.mass_metals + satellite->stellar_mass_metals();
+
+		// Keep track of stars being transfered to the bulge via assembly.
+		central->galaxymergers_assembly_stars.mass += central->disk_stars.mass + satellite->stellar_mass();
+		central->galaxymergers_assembly_stars.mass_metals += central->disk_stars.mass_metals + satellite->stellar_mass_metals();
+
 		central->bulge_gas.mass += central->disk_gas.mass + satellite->gas_mass();
 		central->bulge_gas.mass_metals +=  central->disk_gas.mass_metals + satellite->gas_mass_metals();
 
@@ -418,6 +427,10 @@ void GalaxyMergers::create_merger(GalaxyPtr &central, GalaxyPtr &satellite, Halo
 		central->bulge_stars.mass += satellite->stellar_mass();
 		central->bulge_stars.mass_metals += satellite->stellar_mass_metals();
 
+		// Keep track of stars being transfered to the bulge via assembly.
+		central->galaxymergers_assembly_stars.mass += satellite->stellar_mass();
+		central->galaxymergers_assembly_stars.mass_metals += satellite->stellar_mass_metals();
+
 		// Calculate new angular momentum by adding up the two galaxies.
 		double tot_am = satellite->disk_gas.angular_momentum() + satellite->bulge_gas.angular_momentum();
 		double new_disk_sAM = 0;

src/galaxy_writer.cpp

@@ -206,12 +206,14 @@ void HDF5GalaxyWriter::write_galaxies(hdf5::Writer &file, int snapshot, const st
 	vector<float> mstars_bulge;
 	vector<float> mstars_burst_mergers;
 	vector<float> mstars_burst_diskinstabilities;
+	vector<float> mstars_bulge_assembly;
 	vector<float> mgas_disk;
 	vector<float> mgas_bulge;
 	vector<float> mstars_metals_disk;
 	vector<float> mstars_metals_bulge;
 	vector<float> mstars_metals_burst_mergers;
 	vector<float> mstars_metals_burst_diskinstabilities;
+	vector<float> mstars_metals_bulge_assembly;
 	vector<float> mgas_metals_disk;
 	vector<float> mgas_metals_bulge;
 	vector<float> mmol_disk;
@@ -326,6 +328,7 @@ void HDF5GalaxyWriter::write_galaxies(hdf5::Writer &file, int snapshot, const st
 				mstars_bulge.push_back(galaxy->bulge_stars.mass);
 				mstars_burst_mergers.push_back(galaxy->galaxymergers_burst_stars.mass);
 				mstars_burst_diskinstabilities.push_back(galaxy->diskinstabilities_burst_stars.mass);
+				mstars_bulge_assembly.push_back(galaxy->galaxymergers_assembly_stars.mass);
 				mean_stellar_age.push_back(galaxy->mean_stellar_age / galaxy->total_stellar_mass_ever_formed);
 
 				// Gas components
@@ -337,6 +340,7 @@ void HDF5GalaxyWriter::write_galaxies(hdf5::Writer &file, int snapshot, const st
 				mstars_metals_bulge.push_back(galaxy->bulge_stars.mass_metals);
 				mstars_metals_burst_mergers.push_back(galaxy->galaxymergers_burst_stars.mass_metals);
 				mstars_metals_burst_diskinstabilities.push_back(galaxy->diskinstabilities_burst_stars.mass);
+				mstars_metals_bulge_assembly.push_back(galaxy->galaxymergers_assembly_stars.mass_metals);
 
 				// Metals of the gas components.
 				mgas_metals_disk.push_back(galaxy->disk_gas.mass_metals);
@@ -482,12 +486,14 @@ void HDF5GalaxyWriter::write_galaxies(hdf5::Writer &file, int snapshot, const st
 	REPORT(mstars_bulge);
 	REPORT(mstars_burst_mergers);
 	REPORT(mstars_burst_diskinstabilities);
+	REPORT(mstars_bulge_assembly);
 	REPORT(mgas_disk);
 	REPORT(mgas_bulge);
 	REPORT(mstars_metals_disk);
 	REPORT(mstars_metals_bulge);
 	REPORT(mstars_metals_burst_mergers);
 	REPORT(mstars_metals_burst_diskinstabilities);
+	REPORT(mstars_metals_bulge_assembly);
 	REPORT(mean_stellar_age);
 	REPORT(mgas_metals_disk);
 	REPORT(mgas_metals_bulge);
@@ -567,6 +573,9 @@ void HDF5GalaxyWriter::write_galaxies(hdf5::Writer &file, int snapshot, const st
 	comment = "stellar mass formed via starbursts driven by disk instabilities [Msun/h]";
 	file.write_dataset("galaxies/mstars_burst_diskinstabilities", mstars_burst_diskinstabilities, comment);
 
+	comment = "stellar mass in the bulge brought via galaxy mergers (but that formed in disks) [Msun/h]";
+	file.write_dataset("galaxies/mstars_bulge_assembly", mstars_bulge_assembly, comment);
+
 	comment = "total gas mass in the disk [Msun/h]";
 	file.write_dataset("galaxies/mgas_disk", mgas_disk, comment);
 
@@ -585,6 +594,9 @@ void HDF5GalaxyWriter::write_galaxies(hdf5::Writer &file, int snapshot, const st
 	comment = "mass of metals locked in stars that formed via starbursts driven by disk instabilities [Msun/h]";
 	file.write_dataset("galaxies/mstars_metals_burst_diskinstabilities", mstars_metals_burst_diskinstabilities, comment);
 
+	comment = "mass of metals locked in stars in the bulge that was brought via galaxy mergers (but that formed in disks) [Msun/h]";
+	file.write_dataset("galaxies/mstars_metals_bulge_assembly", mstars_metals_bulge_assembly, comment);
+
 	comment = "stellar mass-weighted stellar age [Gyr]";
 	file.write_dataset("galaxies/mean_stellar_age", mean_stellar_age, comment);