Simulate
See also: introductory tutorial on how to simulate a cluster.
ocelot.simulate.cluster.SimulatedCluster
¤
A class for simulating and keeping track of a simulated cluster - including its original membership list and any observations simulated from it.
This class is the main entry point in ocelot for simulating star clusters.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
parameters
|
SimulatedClusterParameters or dict
|
Parameters of the simulated cluster to generate. Should be a SimulatedClusterParameters object, but may also be a dict with keys for required parameters such as position, etc. |
required |
models
|
(SimulatedClusterModels, dict or None)
|
SimulatedClusterModels object or dict containing models used to overwrite or augment certain simulation features. Default: None |
None
|
prune_simulated_cluster
|
str
|
Optional string used early during cluster simulation to prune a simulated cluster. Will be passed to pandas.DataFrame.query(). It can access parameters read directly from cluster isochrones, including magnitude, temperature, and luminosity. Default: "" |
''
|
random_seed
|
int or None
|
Random seed to use for cluster generation. When set, cluster generation with the same seed should be identical. Default: None |
None
|
features
|
SimulatedClusterFeatures or dict or None
|
A SimulatedClusterFeatures or dict object specifying features of cluster generation to turn off. Mostly intended to aid with testing. Default: None |
None
|
observations
|
list of str or None
|
List of observations to generate. Soon to be deprecated; do not use. |
None
|
Attributes:
| Name | Type | Description |
|---|---|---|
isochrone |
DataFrame
|
Dataframe containing the isochrone used to simulate this cluster. |
cluster |
DataFrame
|
Dataframe containing the true members of the cluster. |
observations |
dict of pd.DataFrame
|
Dict of dataframes, with each one containing a different observation of the same cluster. |
_check_if_has_enough_stars()
¤
Checks if the cluster has enough stars.
make()
¤
Makes entire cluster according to specification set at initialization.
This is the main function that should be used to simulate a cluster.
Returns:
| Type | Description |
|---|---|
SimulatedCluster
|
A reference to the SimulatedCluster object. |
make_cluster()
¤
Creates the true stars and positions in a cluster.
In general, just calling .make() is the recommended method for most users.
Returns:
| Type | Description |
|---|---|
SimulatedCluster
|
A reference to the SimulatedCluster object. |
make_observations()
¤
Makes all observations of the cluster.
In general, just calling .make() is the recommended method for most users.
Returns:
| Type | Description |
|---|---|
SimulatedCluster
|
A reference to the SimulatedCluster object. |
make_observation(survey, seed=None)
¤
Makes one observation of the cluster.
In general, just calling .make() is the recommended method for most users.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
survey
|
str
|
Name of the survey (i.e. name in self.observations) to make. |
required |
seed
|
None
|
Seed used to reseed the random generator. Useful for doing multiple different simulated observations of the same cluster. May not be supported by all cluster observation models. Default: None, meaning that the current cluster random number generator generated from the seed specified during class initialization is used. |
None
|
Returns:
| Type | Description |
|---|---|
DataFrame
|
The simulated cluster observation made by this method. |
ocelot.simulate.cluster.SimulatedClusterParameters
dataclass
¤
Class for keeping track of parameters specified for a cluster to simulate.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
position
|
SkyCoord
|
Position of the cluster as an astropy SkyCoord. Must have full 3D distance and 3D velocity information. |
required |
mass
|
float
|
Mass of the cluster in solar masses. |
required |
log_age
|
float
|
Age of the cluster in log (base 10) years. |
required |
metallicity
|
float
|
The metallicity of the cluster, [Fe/H]. |
required |
r_core
|
float
|
The core radius of the cluster, in parsecs. |
required |
r_tidal
|
float
|
The tidal radius of the cluster, in parsecs. |
required |
extinction
|
float
|
The extinction (A_V / A_0) of the cluster in magnitudes. |
required |
differential_extinction
|
float
|
Amount of differential extinction to apply to the cluster, also in magnitudes. Default: 0. |
0.0
|
minimum_stars
|
int
|
Specify the minimum number of stars the cluster can have. Default: 0 |
1
|
virial_ratio
|
float
|
Virial ratio of the cluster. Acts as a square-root scale factor to the cluster's velocity dispersion. Default: 0.5, meaning that the cluster is virialized. |
0.5
|
eta_virial_ratio
|
float
|
Scale factor of the 1D velocity dispersion equation. Default: 10, which is a good approximation for most clusters. |
10.0
|
id
|
int
|
ID of the simulated cluster. When set, this allows for unique identification of different simulated clusters. Default: 0. |
0
|
Attributes:
| Name | Type | Description |
|---|---|---|
r_50 |
float
|
The half-light radius of the cluster in parsecs. |
velocity_dispersion_1d |
float
|
The 1D velocity dispersion of the cluster in metres per second. |
ocelot.simulate.cluster.SimulatedClusterModels
dataclass
¤
Class for keeping track of all models that a generated SimulatedCluster will use.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
distribution
|
BaseClusterDistributionModel or None
|
The distribution model for the cluster. Must be an instance of BaseClusterDistributionModel. Default: None, meaning that a King62 model is used |
None
|
binaries
|
BaseBinaryStarModel or None
|
The binary star model for the cluster. Must be an instance of BaseBinaryStarModel. Default: None, meaning that a MoeDiStefanoMultiplicityRelation (with Duchene-Kraus+13 below 1 MSun) is used. |
None
|
differential_reddening
|
BaseDifferentialReddeningModel or None
|
The differential reddening model for the cluster. Must be an instance of BaseDifferentialReddeningModel. Default: None, meaning that a FractalDifferentialReddening model is used. |
None
|
observations
|
list or tuple of BaseObservation
|
A list or tuple of observation models for the cluster. Each model must be an instance of a BaseObservation. These observation models will be iterated through when generating cluster observations to generate as many (or few) observation simulations of a cluster as you'd like. Observation models must be unique. Default: None, meaning that no cluster observation simulation will be generated. |
tuple()
|
Attributes:
| Name | Type | Description |
|---|---|---|
observations_dict |
dict of BaseObservation models
|
Same as the observations parameter, but with observations instead organized into a dictionary. |
initialise_defaults(parameters, seed)
¤
For all class attributes, replace None values with sensible default models.
This method is called during simulated cluster generation and should not need to be used by users.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
parameters
|
SimulatedClusterParameters
|
The parameters of the cluster to simulate. |
required |
seed
|
int
|
Random seed to use for default models that incorporate randomness. |
required |
with_default_options(parameters, seed)
staticmethod
¤
Return an instance of a SimulatedClusterModels model with default options.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
parameters
|
SimulatedClusterParameters
|
The parameters of the cluster to simulate. |
required |
seed
|
int
|
Random seed to use for default models that incorporate randomness. |
required |
Returns:
| Type | Description |
|---|---|
SimulatedClusterModels
|
An instance of SimulatedClusterModels with default options already set up. |
ocelot.simulate.cluster.SimulatedClusterFeatures
dataclass
¤
Class for keeping track of all features used to simulate a cluster.
This class mostly exists to aid in testing parts of ocelot.simulate with certain physical effects turned on or off.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
binary_stars
|
bool
|
Whether or not to simulate binary stars in the cluster. Default: True |
True
|
differential_extinction
|
bool
|
Whether or not to simulate differential extinction of the cluster. Default: True |
True
|
selection_effects
|
bool
|
Whether or not to simulate selection effects in simulated observations of the cluster. Default: True |
True
|
astrometric_uncertainties
|
bool
|
Whether or not to apply astrometric uncertainties to observations of the cluster. Default: True |
True
|
photometric_uncertainties
|
bool
|
Whether or not to apply photometric uncertainties to observations of the cluster. Default: True |
True
|