CAESAR Module

class main.CAESAR(ds=0, *args, **kwargs)[source]

Bases: object

Master CAESAR class.

CAESAR objects contain all references to halos, galaxies, and clouds for a single snapshot. Its output format is portable and global object statistics can be examined without the raw simulation file.

Parameters

  • ds (yt dataset, optional) – A dataset via ds = yt.load(snapshot)

  • mass (str, optional) – Mass unit to store data with. Defaults to ‘Msun’.

  • length (str, optional) – Length unit to store data with. Defaults to ‘kpccm’.

  • velocity (str, optional) – Velocity unit to store data with. Defaults to ‘km/s’.

  • time (str, optional) – Time unit to store data with. Defaults to ‘yr’.

  • temperature (str, optional) – Temperature unit to store data with. Defaults to ‘K’.

Examples

>>> import caesar
>>> obj = caesar.CAESAR()
cloudinfo(top=10)[source]

Method to print general info for the most massive clouds identified via CAESAR.

Parameters

top (int, optional) – Number of results to print. Defaults to 10.

Notes

This prints to terminal, and is meant for use in an interactive session.

property data_manager

On demand DataManager class.

galinfo(top=10)[source]

Method to print general info for the most massive galaxies identified via CAESAR.

Parameters

top (int, optional) – Number of results to print. Defaults to 10.

Notes

This prints to terminal, and is meant for use in an interactive session.

haloinfo(top=10)[source]

Method to print general info for the most massive halos identified via CAESAR.

Parameters

top (int, optional) – Number of results to print. Defaults to 10.

Notes

This prints to terminal, and is meant for use in an interactive session.

Meat and potatoes of CAESAR.

This method is responsible for loading particle/field data from disk, creating halos, galaxies and clouds, linking objects together, and finally calculating HI/H2 masses if necessary.

Parameters

  • unbind_halos (boolean, optional) – Unbind halos? Defaults to False

  • unbind_galaxies (boolean, optional) – Unbind galaxies? Defaults to False

  • b_halo (float, optional) – Quantity used in the linking length (LL) for halos. LL = mean_interparticle_separation * b_halo. Defaults to b_halo = 0.2.

  • b_galaxy (float, optional) – Quantity used in the linking length (LL) for galaxies. LL = mean_interparticle_separation * b_galaxy. Defaults to b_galaxy = b_halo * 0.2.

  • ll_cloud (float, optional) – Quantity used in the linking length (LL) for clouds in comoving kpc (kpccm).

  • fofclouds (boolean,optional) – Indicates if we’re running 3D fof on clouds. Default is that this is set to false

  • fof6d (boolean, optional) – Indicates if we’re running galaxy finding with 6D FOF vs the default of 3D FOF

  • fof6d_LL_factor (float, optional) – Sets linking length for fof6d

  • fof6d_mingrp (float, optional) – Sets minimum group size for fof6d

  • fof6d_velLL (float, optional) – Sets linking length for velocity in fof6d

  • nproc (int, optional) – Sets number of processors for fof6d and progen_rad

  • blackholes (boolean, optional) – Indicate if blackholes are present in your simulation. This must be toggled on manually as there is no clear cut way to determine if PartType5 is a low-res particle, or a black hole.

  • dust (boolean, optional) – Indicate if active dust particles are present in your simulation. This must be toggled on manually as there is no clear cut way to determine if PartType3 is a low-res particle, or an active dust particle.

  • lowres (list, optional) – If you are running CAESAR on a Gadget/GIZMO zoom simulation in HDF5 format, you may want to check each halo for low-resolution contamination. By passing in a list of particle types (ex. [2,3,5]) we will check ALL objects for contamination and add the contamination attribute to all objects. Search distance defaults to 2.5x radii[‘total’].

Examples

>>> obj.member_search(blackholes=False)
reset_default_returns(group_type='all')[source]

Reset the default returns for object dictionaries.

This function resets the default return quantities for CAESAR halo/galaxy/cloud objects including mass, radius, sigma, metallicity, and temperature.

Parameters

  • obj (main.CAESAR) – Main CAESAR object.

  • group_type ({'all', 'halo', 'galaxy', 'cloud'}, optional) – Group to reset return values for.

save(filename)[source]

Save CAESAR file.

Parameters

filename (str) – The name of the output file.

Examples

>>> obj.save('output.hdf5')
set_default_cloud_returns(category, value)[source]

Set the default return quantity for a given cloud attribute.

Parameters

  • category (str) – The attribute to redirect to a different quantity.

  • value (str) – The internal name of the new quantity which must be present in the dictinoary

set_default_galaxy_returns(category, value)[source]

Set the default return quantity for a given galaxy attribute.

Parameters

  • category (str) – The attribute to redirect to a different quantity.

  • value (str) – The internal name of the new quantity which must be present in the dictinoary

set_default_halo_returns(category, value)[source]

Set the default return quantity for a given halo attribute.

Parameters

  • category (str) – The attribute to redirect to a different quantity.

  • value (str) – The internal name of the new quantity which must be present in the dictinoary

vtk_vis(**kwargs)[source]

Method to visualize an entire simulation with VTK.

Parameters

  • obj (main.CAESAR) – Simulation object to visualize.

  • ptypes (list) – List containing one or more of the following: ‘dm’,’gas’,’star’, which dictates which particles to render.

  • halo_only (boolean) – If True only render particles belonging to halos.

  • galaxy_only (boolean) – If True only render particles belonging to galaxies. Note that this overwrites halo_only.

  • annotate_halos (boolean, list, int, optional) – Add labels to the render at the location of halos annotating the group ID and total mass. If True then all halos are annotated, if an integer list then halos of those indexes are annotated, and finally if an integer than the most massive N halos are annotated.

  • annotate_galaxies (boolean, list, int, optional) – Add labels to the render at the location of galaxies annotating the group ID and total mass. If True then all galaxies are annotated, if an integer list then galaxies of those indexes are annotated, and finally if an integer than the most massive N galaxies are annotated.

property yt_dataset

The yt dataset to perform actions on.