linefinder.classify module

Tools for categorizing particles into different accretion modes.

@author: Daniel Angles-Alcazar, Zach Hafen @contact: zachary.h.hafen@gmail.com @status: Development

class linefinder.classify.Classifier(out_dir, tag, ptracks_tag=<object object>, galids_tag=<object object>, halo_data_dir=<object object>, mtree_halos_index=<object object>, halo_file_tag=<object object>, not_in_main_gal_key='gal_id', classifications_to_save=['is_unaccreted', 'is_pristine', 'is_preprocessed', 'is_merger', 'is_mass_transfer', 'is_wind', 'is_hitherto_EP', 'is_hitherto_NEP', 'is_unaccreted_EP', 'is_unaccreted_NEP'], write_events=True, events_to_save=['is_in_other_gal', 'is_in_main_gal', 'is_accreted', 'is_ejected', 'redshift_first_acc', 'ind_first_acc', 'cumulative_time_in_other_gal', 'gal_event_id', 'time_in_other_gal_before_acc_during_interval', 'is_in_other_CGM'], velocity_scale='Vmax', wind_cut=1.0, absolute_wind_cut=15.0, t_pro=0.03, t_m=0.5, neg=10, main_halo_robustness_criteria='n_star', main_halo_robustness_value=100, min_gal_density=0.173, pp_classifications_to_save=['is_in_CGM', 'is_in_CGM_not_sat', 'is_in_galaxy_halo_interface', 'is_CGM_IGM_accretion', 'is_CGM_wind', 'is_CGM_satellite_wind', 'is_CGM_satellite_ISM', 'CGM_fate_classifications'])

Bases: object

Loads the tracked particle data, and uses that to classify the particles into different categories.

additional_postprocessing(pp_classifications_to_save)

Save additional classifications that are available as part of the analysis suite, but are not computed here.

Parameters:pp_classifications_to_save (list of strs) – Classifications available as part of Worldlines that will be saved in the classifications_*.hdf5 file.

calc_gal_event_id()

Identify potential accretion/ejection events relative to main galaxy at each redshift

Returns:GalEvent = 0 (no change), 1 (entering galaxy), -1 (leaving galaxy) at that redshift Return type:gal_event_id ( [n_particle, n_snap-1] np.ndarray of ints)

classify_particles()

Run the full classification suite.

get_circular_velocity()

Get the circular velocity of the halo (measured at Rvir).

Returns:Circular velocity of the halo in km/s, indexed the same way that ahf_reader.mtree_halos[i] is. Return type:v_c

get_cum_num_acc()

Get the cumulative number of accretions so far.

Returns:Cumulative number of accretion events for that particles. Return type:cum_num_acc ([n_particle, n_snap-1] np.ndarray of ints)

get_cumulative_time_in_other_gal()

Get the amount of time in galaxies besides the main galaxy before being accreted.

For a single time in another galaxy, this is the ( age of universe at the last snapshot before the conditions are true ) - ( age of the universe at the last snapshot where the conditions are true ), and generalizes to multiple events in other galaxies.

Returns:

cumulative_time_in_other_gal ([ n_particle, n_snap ]

np.ndarray of floats): Time in another galaxy at a given snapshot.

get_radial_velocity()

Get the radial velocity of particles, relative to the main galaxy.

Returns:The radial velocity of each particle at that redshift, relative to the main galaxy. Return type:v_r ( [n_particle, n_snap] np.ndarray )

get_redshift_first_acc()

Get the redshift of first accretion.

Returns:Redshift of first accretion. Return type:redshift_first_acc ([n_particle,] np.ndarray of floats)

get_time_difference()

Get the time between snapshots.

Returns:Time between snapshots in Myr. Return type:dt ([n_particle, n_snap-1] np.array)

get_time_in_other_gal_before_acc()

Get the amount of time in galaxies besides the main galaxy before being accreted. For a single time in another galaxy, this is the ( age of universe at the last snapshot before the conditions are true ) - ( age of the universe at the last snapshot where the conditions are true ), and generalizes to multiple events in other galaxies.

Returns:Time in another galaxy before being first accreted onto the main galaxy. Return type:time_in_other_gal_before_acc ([ n_particle, ] np.ndarray of floats)

get_time_in_other_gal_before_acc_during_interval()

Get the amount of time in galaxies besides the main galaxy before being accreted, during an interval before being accreted.

Returns:time_in_other_gal_before_acc_during_interval ([ n_particle, ] np.ndarray of floats) :

Time in another galaxy before being first accreted onto the main galaxy, within some recent time interval

get_velocity_scale()

Get the characteristic velocity scale.

Returns:Velocity of the halo in proper km/s. Return type:velocity_scale (np.ndarray)

identify_accretion()

Identify ALL gas/star accretion events, i.e. whether or not a particle was outside the galaxy at one redshift, and inside at the next

identify_ejection()

Identify ALL gas wind ejection events. These conditions must be met to identify as ejection:

1. Inside the main galaxy at one snapshot, and not at the previous snapshot.

2. Radial velocity of the particle relative to the main galaxy

   must be greater than some fraction of the circular velocity of the main galaxy.

3. Radial velocity of the particle relative to the main galaxy

   must be greater than some base speed.

4. The particle must be a gas particle.
5. The particle must be outside any other galaxy.

identify_hitherto_EP()

Identify particles that have been processed by another galaxy by the tabulated snapshot.

Returns:True for particle i at snapshot j if it has spent at least t_pro in another galaxy by that point. Return type:is_hitherto_EP ( [n_particle,n_snap] np.ndarray of bools )

identify_hitherto_NEP()

Identify particles that have not been processed by another galaxy by the tabulated snapshot.

Returns:True for particle i at snapshot j if it has not spent at least t_pro in another galaxy by that point. Return type:is_hitherto_EP ( [n_particle,n_snap] np.ndarray of bools )

identify_is_before_first_acc()

Identify when before a particle’s first accretion event.

Returns:If True, then the first accretion event for that particle hasn’t happened yet. Return type:is_before_first_acc ([n_particle, n_snap-1] np.ndarray of bools)

identify_is_in_main_gal()

Identify what particles are in a main galaxy. They must be in the main galaxy and not inside any other galaxy at that redshift, even a subhalo galaxy.

Returns:True if in the main galaxy (and not any other galaxy) at that redshift. Return type:is_in_main_gal ( [n_particle, n_snap-1] np.ndarray of bools)

identify_is_in_other_CGM()

Identify what particles are in a CGM besides the main CGM.

Returns:True if in a CGM other than the main CGM at that redshift. Return type:is_in_other_cgm ( [n_particle, n_snap-1] np.ndarray of bools)

identify_is_in_other_gal()

Identify what particles are in a galaxy besides the main galaxy.

Returns:True if in a galaxy other than the main galaxy at that redshift. Return type:is_in_other_gal ( [n_particle, n_snap-1] np.ndarray of bools)

identify_mass_transfer()

Boolean for whether or no particles are from mass transfer

Returns:True for particle i if it has been preprocessed but has not spent at least some minimum amount of time in another galaxy in a recent interval. Return type:is_mass_transfer (np.ndarray of bools)

identify_merger()

Boolean for whether or no particles are from galaxies merging.

Returns:True for particle i if it has been preprocessed and has spent at least some minimum amount of time in another galaxy in a recent interval. Return type:is_merger ( [n_particle] np.ndarray of bools )

identify_preprocessed()

Identify pre-proceesed gas, or “externally processed” gas.

Returns:True for particle i if it has spent at least some minimum amount of time in another galaxy before being accreted. Return type:is_preprocessed ( [n_particle] np.ndarray of bools )

identify_pristine()

Identify pristine gas, or “non-externally processed” gas.

Returns:True for particle i if it has never spent some minimum amount of time in another galaxy before being accreted. Return type:is_pristine ( [n_particle] np.ndarray of bools )

identify_unaccreted()

Identify particles never accreted onto the main galaxy.

Returns:True for particle i if it has never been inside the main galaxy. Return type:is_unaccreted ( [n_particle,] np.ndarray of bools )

identify_unaccreted_EP()

Identify particles never accreted onto the main galaxy that have spent at least t_pro in another galaxy by the specified snapshot.

Returns:True for particle i at snapshot j if it has spent at least t_pro in another galaxy by that point and never accretes onto the main galaxy. Return type:is_unaccreted_EP ( [n_particle,n_snap] np.ndarray of bools )

identify_unaccreted_NEP()

Identify particles never accreted onto the main galaxy that have not spent at least t_pro in another galaxy by the specified snapshot.

Returns:True for particle i at snapshot j if it has not spent at least t_pro in another galaxy by that point. Return type:is_unaccreted_NEP ( [n_particle,n_snap] np.ndarray of bools )

identify_wind()

Boolean for whether or not particles are from wind.

Returns:True for particle i if it has been ejected at least once before snapshot n Return type:is_wind ( [n_particle] np.ndarray of bools )

ind_first_acc

Get the index of first accretion. This is defined as the the indice immediately after accretion happens.

Returns:Index of first accretion. Return type:ind_first_acc ([n_particle,] np.ndarray of floats)

ind_first_snap

Find the indice for first snapshot at which the main merger tree halo is resolved.

main_mt_halo_first_snap

Find the first snapshot at which the main merger tree halo is resolved.

meets_density_requirement

Find particles that are either stars or have sufficient density to be counted as part of a galaxy.

read_data_files()

Read the relevant data files, and store the data in a dictionary for easy access later on.

save_classifications(classifications_to_save)

Save the results of running the classifier.

Parameters:classifications_to_save (list of strs) – What classifications to save to the file.

save_events(events_to_save)

Save the particular events, identified during the classification process.

Parameters:events_to_save (list of strs) – What events to save to the file.