Bayesian Analysis of Neutron Star Mass and Radius Observations
Public Member Functions | Protected Attributes
bamr::two_polytropes Class Reference

Two polytropes. More...

Detailed Description

Based on the model from Steiner10te. The original limits on the parameters are maintained here.

For a polytrope $ P = K \varepsilon^{1+1/n} $ beginning at a pressure of $ P_1 $, an energy density of $ \varepsilon_1 $ and a baryon density of $ n_{B,1} $, the baryon density along the polytrope is

\[ n_B = n_{B,1} \left(\frac{\varepsilon}{\varepsilon_1}\right)^{1+n} \left(\frac{\varepsilon_1+P_1}{\varepsilon+P}\right)^{n} \, . \]

Similarly, the chemical potential is

\[ \mu_B = \mu_{B,1} \left(1 + \frac{P_1}{\varepsilon_1}\right)^{1+n} \left(1 + \frac{P}{\varepsilon}\right)^{-(1+n)} \, . \]

The expression for the baryon density can be inverted to determine $ \varepsilon(n_B) $

\[ \varepsilon(n_B) = \left[ \left(\frac{n_{B,1}} {n_B \varepsilon_1} \right)^{1/n} \left(1+\frac{P_1}{\varepsilon_1}\right)-K\right]^{-n} \, . \]

Sometimes the baryon susceptibility is also useful

\[ \frac{d \mu_B}{d n_B} = \left(1+1/n\right) \left( \frac{P}{\varepsilon}\right) \left( \frac{\mu_B}{n_B}\right) \, . \]

Definition at line 145 of file models.h.

#include <models.h>

Inheritance diagram for bamr::two_polytropes:
bamr::model bamr::alt_polytropes bamr::fixed_pressure bamr::generic_quarks bamr::qmc_fixp bamr::qmc_neut bamr::qmc_twop bamr::quark_star

Public Member Functions

virtual void setup_params (o2scl::cli &cl)
 Setup new model parameters.
 
virtual void remove_params (o2scl::cli &cl)
 Remove model-specific parameters.
 
virtual void baryon_density_point (double &n1, double &e1)
 A point to calibrate the baryon density with. More...
 
 two_polytropes ()
 Create a model object.
 
virtual void low_limits (entry &e)
 Set the lower boundaries for all the parameters, masses, and radii.
 
virtual void high_limits (entry &e)
 Set the upper boundaries for all the parameters, masses, and radii.
 
virtual std::string param_name (size_t i)
 Return the name of parameter with index i.
 
virtual std::string param_unit (size_t i)
 Return the unit of parameter with index i.
 
virtual void compute_eos (entry &e, int &success, std::ofstream &scr_out)
 Compute the EOS corresponding to parameters in e and put output in tab_eos.
 
virtual void first_point (entry &e)
 Function to compute the initial guess.
 
- Public Member Functions inherited from bamr::model
virtual void compute_mr (entry &e, std::ofstream &scr_out, o2scl::o2_shared_ptr< o2scl::table_units<> >::type tab_mvsr, int &success)
 Compute the M-R curve directly.
 

Protected Attributes

o2scl::cli::parameter_double p_kin_sym
 Parameter for kinetic part of symmetry energy.
 
o2scl::eos_had_schematic se
 Low-density EOS.
 
o2scl::fermion neut
 Neutron for se.
 
o2scl::fermion prot
 Proton for se.
 
double nb_n1
 The fiducial baryon density.
 
double nb_e1
 The fiducial energy density.
 

Additional Inherited Members

- Data Fields inherited from bamr::model
nstar_cold2 cns
 TOV solver and storage for the EOS table.
 

Member Function Documentation

virtual void bamr::two_polytropes::baryon_density_point ( double &  n1,
double &  e1 
)
inlinevirtual

This just returns nb_n1 and nb_e1, which are computed in compute_eos().

Reimplemented from bamr::model.

Definition at line 180 of file models.h.

The documentation for this class was generated from the following file:

Documentation generated with Doxygen. Bamr documentation is under the GNU Free Documentation License.