Note
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Generating Lines from a Parametric Galaxy¶
In this example we’re going to generate emission line predictions for a parametric galaxy.
+-------------------------------------------------------------------------------+
| GALAXY |
+---------------+---------------------------------------------------------------+
| Attribute | Value |
+---------------+---------------------------------------------------------------+
| galaxy_type | 'Parametric' |
+---------------+---------------------------------------------------------------+
| stars | <synthesizer.parametric.stars.Stars object at 0x7f500dd392d0> |
+---------------+---------------------------------------------------------------+
| name | 'parametric galaxy' |
+---------------+---------------------------------------------------------------+
| sfzh (51, 13) | 0.00e+00 -> 5.84e+07 (Mean: 4.77e+05) |
+---------------+---------------------------------------------------------------+
----------
LINE COLLECTION
number of lines: 5
lines: ['H 1 4861.32A' 'O 3 4958.91A,O 3 5006.84A,H 1 4861.32A' 'O 3 4958.91A'
'O 3 4958.91A,O 3 5006.84A' 'O 3 5006.84A']
available ratios: ['R3']
available diagrams: []
----------
----------
SUMMARY OF H 1 4861.32A
wavelength: 4861.3 Å
Npart: 1
<log10(luminosity/erg/s)>: -inf
<equivalent width>: 0 Å
----------
----------
SUMMARY OF O 3 4958.91A, O 3 5006.84A, H 1 4861.32A
wavelength: 4942.4 Å
Npart: 1
<log10(luminosity/erg/s)>: -inf
<equivalent width>: 0 Å
----------
----------
SUMMARY OF O 3 4958.91A
wavelength: 4958.9 Å
Npart: 1
<log10(luminosity/erg/s)>: -inf
<equivalent width>: 0 Å
----------
----------
SUMMARY OF O 3 4958.91A, O 3 5006.84A
wavelength: 4982.9 Å
Npart: 1
<log10(luminosity/erg/s)>: -inf
<equivalent width>: 0 Å
----------
----------
SUMMARY OF O 3 5006.84A
wavelength: 5006.8 Å
Npart: 1
<log10(luminosity/erg/s)>: -inf
<equivalent width>: 0 Å
----------
+-------------------------------------------------------------------------------+
| GALAXY |
+---------------+---------------------------------------------------------------+
| Attribute | Value |
+---------------+---------------------------------------------------------------+
| galaxy_type | 'Parametric' |
+---------------+---------------------------------------------------------------+
| stars | <synthesizer.parametric.stars.Stars object at 0x7f500dd392d0> |
+---------------+---------------------------------------------------------------+
| name | 'parametric galaxy' |
+---------------+---------------------------------------------------------------+
| sfzh (51, 13) | 0.00e+00 -> 5.84e+07 (Mean: 4.77e+05) |
+---------------+---------------------------------------------------------------+
----------
LINE COLLECTION
number of lines: 5
lines: ['H 1 4861.32A' 'O 3 4958.91A,O 3 5006.84A,H 1 4861.32A' 'O 3 4958.91A'
'O 3 4958.91A,O 3 5006.84A' 'O 3 5006.84A']
available ratios: ['R3']
available diagrams: []
----------
from unyt import Msun, Myr
import synthesizer.line_ratios as line_ratios
from synthesizer.emission_models import AttenuatedEmission, IncidentEmission
from synthesizer.emission_models.attenuation import PowerLaw
from synthesizer.grid import Grid
from synthesizer.parametric import SFH, Stars, ZDist
from synthesizer.parametric.galaxy import Galaxy
if __name__ == "__main__":
# Begin by defining and initialising the grid.
grid_name = "test_grid"
grid_dir = "../../tests/test_grid/"
grid = Grid(grid_name, grid_dir=grid_dir)
# Define the emission model
incident = IncidentEmission(grid)
# Let's now build a galaxy following the other tutorials:
# Define the functional form of the star formation and metal
# enrichment histories
# Constant star formation
sfh = SFH.Constant(max_age=100 * Myr)
# Constant metallicity
metal_dist = ZDist.DeltaConstant(log10metallicity=-2.0)
# Get the 2D star formation and metal enrichment history
# for the given SPS grid. This is (age, Z).
stars = Stars(
grid.log10age,
grid.metallicity,
sf_hist=sfh,
metal_dist=metal_dist,
initial_mass=10**8.5 * Msun,
)
# Create the Galaxy object
galaxy = Galaxy(stars)
# Print a summary of the Galaxy object
print(galaxy)
# Let's define a list of lines that we're interested in. Note that we can
# provide multiples which are automatically summed as if they were blended.
line_ids = [
line_ratios.Hb, # "H 1 4861.32A"
line_ratios.O3b, # "O 3 4958.91A"
line_ratios.O3r, # "O 3 5006.84A"
line_ratios.O3, # ["O 3 4958.91A", "O 3 5006.84A"]
line_ratios.O3
+ ","
+ line_ratios.Hb, # ["O 3 4958.91A", "O 3 5006.84A", "H 1 4861.32A"]
]
# Next, let's get the intrinsic line properties:
lines = galaxy.stars.get_lines(line_ids, incident)
# This produces a LineCollection object which has some useful methods and
# information.
print(lines)
# Let's now examine individual lines (or doublets):
for line in lines:
print(line)
# Those lines are now associated with the `Galaxy` object, revealed by
# using the print function:
print(galaxy)
# Next, lets get the attenuated line properties:
model = AttenuatedEmission(
emitter="stellar",
tau_v=1.0,
dust_curve=PowerLaw(slope=-1),
apply_dust_to=incident,
)
lines_att = galaxy.stars.get_lines(
line_ids,
model,
)
print(lines_att)
Total running time of the script: (0 minutes 0.335 seconds)