Package to read Sibelius-DARK simulation data

Reads the catalog information from HBT, Velociraptor and GALFORM outputs from the Sibelius-DARK simulation.

Installation via:

git clone https://github.com/stuartmcalpine/pysibeliusdark.git
cd pysibeliusdark
python3 -m pip install .

Reading GALFORM galaxies

Output data in the GALFORM directory is expected to be split over multiple ivol_XXX folders and ivol_XXX_mags directories.

In the MPI reading case, each rank reads its own subset of the ivol_XXX directories. These arrays can then be reduced to rank=0 calling gather_galaxies() (see example below).

Input params to read_galform()

Input	Description	Is optional?	Default option
data_dir	path to GALFORM data (base directory containing the ivol_XXX directories)	No	-
num_files	number of files GALFORM data is split over (number of ivol_XXX directories)	No	-
output_no	output/snapshot number (int, 1 is redshift=0)	No	-
comm=	MPI4PY communicator	Yes	None
verbose=	True for more stdout output	Yes	False
ivol_list=	Option to read only a subset of ivols (list of ints)	Yes	None
to_convert_out_h=	True to convert out h-values	Yes	True

Example usage (No MPI case)

import pysibeliusdark.galform as galform

# Set up read_galform object.
data_dir = "/path/to/galform/folder/"
num_files = 1024
output_no = 1 # z=0
g = galform.read_galform(data_dir, num_files, output_no)

# Load galaxy data.
what_to_load = ["SubhaloID", "xgal", "ygal", "zgal"]
g.load_galaxies(what_to_load)

# Link Sibelius-DARK specific properties (ra, dec, vr, etc).
g.link_sibelius()

# Data gets stored in the data dict. Access the data:
print(g.data)

Example usage (MPI case)

from mpi4py import MPI
import pysibeliusdark.galform as galform

# MPI communicator.
comm = MPI.COMM_WORLD

# Set up read_galform object.
data_dir = "/path/to/galform/folder/"
num_files = 1024
output_no = 1 # z=0
g = galform.read_galform(data_dir, num_files, output_no, comm=comm)

# Load galaxy data.
what_to_load = ["SubhaloID", "xgal", "ygal", "zgal"]
g.load_galaxies(what_to_load)

# Link Sibelius-DARK specific properties (ra, dec, vr, etc).
g.link_sibelius()

# Reduce all galaxies to rank 0.
g.gather_galaxies()

# Data gets stored in the data dict. Access the data:
# Only rank 0 will have any data after gather.
print(g.data["xgal"])

Compute Sibelius-DARK properties

When loading galaxies/subhaloes from HBT, Velociraptor or GALFORM the data gets stored in a data dict in the loader object (see examples above). To append Sibelius-DARK specific quantities (such as ra, dec, z) use the link_sibelius() function.

This appends the data dict with:

Attribute in dict	Description
distance : ndarray	Distance from each galaxy to observer (MW)
ra_deg, dec_deg : ndarray	Right ascention and declination of galaxies in degrees
ra_rad, dec_rad : ndarray	Right ascention and declination of galaxies in radians
vt, vr : ndarray	Tangential and radial velocities of galaxies relative to observer
mag_*_app : ndarray	Apparent magnitude of galaxies (if you loaded the absolute magnitudes
l_deg, b_deg : ndarray	Galactic longitude and latitude of galaxies in degrees
l_rad, b_rad : ndarray	Galactic longitude and latitude of galaxies in radians