HI/H2 Mass Calc

hydrogen_mass_calc.assign_halo_gas_to_galaxies(internal_galaxy_pos, internal_galaxy_mass, internal_glist, internal_galaxy_index_list, galaxy_glist, grhoH, gpos, galaxy_HImass, galaxy_H2mass, HImass, H2mass, low_rho_thresh, boxsize, halfbox)

Function to assign halo gas to galaxies.

When we assign galaxies in CAESAR, we only consider dense gas. But when considering HI gas however, it is often desirable to also consider low-density gas ‘outside’ of the galaxy. This function calculates the mass weighted distance to each galaxy within a given halo and assigns low-density gas to the ‘nearest’ galaxy.

Typically called from hydrogen_mass_calc.hydrogen_mass_calc().

hydrogen_mass_calc.check_values(obj)

Check to make sure that we have the required fields available to perform the hydrogen mass frac calculation.

Parameters

obj (main.CAESAR) – Main CAESAR object.

Returns

Returns True if all fields are present, False otherwise.

Return type

bool

hydrogen_mass_calc.hydrogen_mass_calc(obj, **kwargs)

Calculate the neutral and molecular mass contents of SPH particles.

For non star forming gas particles assigned to halos we calculate the neutral fraction based on equations from Popping+09 and Rahmati+13. If H2 block is not present in the simulation file we estimate the neutral and molecular fraciton via Leroy+08. Once these fractions are calculated we assign HI/H2 masses to galaxies & halos based on their mass-weighted distances.

Parameters

obj (main.CAESAR) – Main CAESAR object.

Returns

HImass, H2mass – Contains the HImass and H2 mass of each individual particle.

Return type

np.ndarray, np.ndarray