gcfit.core.SingleMassModel#
- class gcfit.core.SingleMassModel(W0, M, rh, g=1.5, ra=100000000.0, d=5, *, ode_maxstep=10000000000.0, ode_rtol=1e-07)#
Wrapper class around a single-mass LIMEPY model.
Single-mass globular cluster model implemented as a subclass around a limepy.limepy model.
This class differs from the base Model as it solves only for the distribution of a single mass class. This makes the model much quicker to compute, however these models should not be used to describe real clusters, as single mass models fail to account for key cluster processes such as mass segregation, and thus cannot accurately reproduce realistic distributions of stars in GCs.
- Parameters:
- W0float or astropy.Quantity
The (dimensionless) central potential. Used as a boundary condition for solving Poisson’s equation and defines how centrally concentrated the model is.
- Mfloat or astropy.Quantity
The total mass of the system, in all mass components, in Msun.
- rhfloat or astropy.Quantity
The system half-mass radius, in parsecs.
- gfloat, optional
The truncation parameter, which controls the sharpness of the outer density truncation of the model. No finite models exist outside 0 <= g < 3.5. Defaults to 1.5.
- rafloat or astropy.Quantity, optional
The (dimensionless) anisotropy-radius, which determines the amount of anisotropy in the system, with higher ra values indicating more isotropy. This quantity is scaled based on the given rh in physical units.
- dfloat or astropy.Quantity, optional
Distance to the cluster, from Earth, in kiloparsecs. Mainly used for any conversions between observational (angular) and model (linear) units, and thus mostly only required for comparing with observations. Defaults to an arbitrary distance of 5 kpc.
- ode_maxstepfloat, optional
Maximum step size for the limepy ODE integrator. Defaults to 1e10.
- ode_rtolfloat, optional
Relative tolerance parameter for the limepy ODE integrator. Defaults to 1e-7.
- Attributes:
- rastropy.Quantity
The projected radial distances, in pc, from the centre of the cluster, defining the domain used in all other model profiles.
- phiastropy.Quantity
System potential as a function of distance from the centre of the cluster.
- rhoastropy.Quantity
System density as a function of distance from the centre of the cluster.
- v2astropy.Quantity
System mean-square velocity as a function of distance from the centre of the cluster.
- v2r, v2tastropy.Quantity
Radial and Tangential components of the system mean-square velocity, in the plane of the sky, as a function of distance from the centre of the cluster.
- r0, rh, rv, rt, ra, rhpastropy.Quantity
The (King, half-mass, virial, truncation, anisotropy, projected half-mass) radius of the cluster.
Methods
__init__(W0, M, rh[, g, ra, d, ode_maxstep, ...])df(*arg)Returns the value of the normalised DF at a given position in phase space, can only be called after solving Poisson's equation
get_Paz(az_data, R_data, jns)Computes probability of line of sight acceleration at projected R : P(az|R)
interp_phi(r)Returns interpolated potential at r, works on scalar and arrays
isotropic(W0, M, rh, **kw)initialize with no anisotropy.
king(W0, M, rh, **kw)Initialize a King (1966) Model (g=1 and isotropic).
legendre_Ul(l, theta)michieking(W0, M, rh, **kw)Initialize a Michie-King (1963) Model (g=1 and anisotropic).
wilson(W0, M, rh, **kw)Initialize a Wilson (1975) Model (g=2 and isotropic).
woolley(W0, M, rh, **kw)Initialize a Woolley (1954) Model (g=0 and isotropic).
- classmethod isotropic(W0, M, rh, **kw)#
initialize with no anisotropy.
- classmethod king(W0, M, rh, **kw)#
Initialize a King (1966) Model (g=1 and isotropic).
- classmethod michieking(W0, M, rh, **kw)#
Initialize a Michie-King (1963) Model (g=1 and anisotropic).
- classmethod wilson(W0, M, rh, **kw)#
Initialize a Wilson (1975) Model (g=2 and isotropic).
- classmethod woolley(W0, M, rh, **kw)#
Initialize a Woolley (1954) Model (g=0 and isotropic).