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r"""
.. _point-spatial-model:
Point spatial model
===================
This model is a delta function centered in *lon_0* and *lat_0* parameters provided:
.. math:: \phi(lon, lat) = \delta{(lon - lon_0, lat - lat_0)}
The model is defined on the celestial sphere in the coordinate frame provided by the user.
If the point source is not centered on a pixel, the flux is re-distributed
across 4 neighbouring pixels. This ensured that the center of mass position
is conserved.
"""
# %%
# Example plot
# ------------
# Here is an example plot of the model:
from astropy.coordinates import SkyCoord
from gammapy.maps import WcsGeom
from gammapy.modeling.models import (
Models,
PointSpatialModel,
PowerLawSpectralModel,
SkyModel,
)
model = PointSpatialModel(
lon_0="0.01 deg",
lat_0="0.01 deg",
frame="galactic",
)
geom = WcsGeom.create(
skydir=SkyCoord("0d 0d", frame="galactic"), width=(1, 1), binsz=0.1
)
model.plot(geom=geom, add_cbar=True)
# %%
# YAML representation
# -------------------
# Here is an example YAML file using the model:
pwl = PowerLawSpectralModel()
point = PointSpatialModel()
model = SkyModel(spectral_model=pwl, spatial_model=point, name="pwl-point-model")
models = Models([model])
print(models.to_yaml())
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