Aperture Mask Example

Show how to implement fixed spherical apertures when getting the emission from galaxy objects.

import matplotlib.pyplot as plt
import numpy as np
from synthesizer.grid import Grid
from synthesizer.load_data.load_camels import load_CAMELS_IllustrisTNG
from unyt import kpc

grid_dir = "../../tests/test_grid"
grid_name = "test_grid"
grid = Grid(grid_name, grid_dir=grid_dir)

gals = load_CAMELS_IllustrisTNG(
    "../../tests/data/",
    snap_name="camels_snap.hdf5",
    fof_name="camels_subhalo.hdf5",
    fof_dir="../../tests/data/",
)

# Select a single galaxy
gal = gals[1]

# Test calculating the centre manually
print("Galaxy centre from file: gal.centre", gal.centre)

print(
    "Stars centre adopted from parent galaxy: gal.stars.centre",
    gal.stars.centre,
)

gal.stars.calculate_centre_of_mass()

print("Stars centre of mass: gal.stars.centre = ", gal.stars.centre)

print("Galaxy centre unchanged: gal.centre = ", gal.centre)


fig, ax = plt.subplots(1, 1)

for aperture_radius in np.array([30, 10, 5, 2, 1, 0.5]) * kpc:
    spec = gal.stars.get_spectra_incident(grid=grid, aperture=aperture_radius)

    ax.loglog(spec.lam, spec.lnu, label=f"Aperture: {aperture_radius.value}")

ax.set_ylim(1e20, 1e30)
ax.set_xlim(1e2, 2e4)
ax.legend()
ax.set_xlabel("$\\lambda \\,/\\, \\AA$")
ax.set_ylabel("$L_{\\lambda} / \\mathrm{erg / Hz / s}$")

plt.show()