NcHaloBiasSTSpher

NcHaloBiasSTSpher — Sheth-Tormen spherical halo bias function type.

Functions

Properties

double a Read / Write / Construct Only
double critical-delta Read / Write / Construct Only
double p Read / Write / Construct Only

Object Hierarchy

    GObject
    ╰── NcHaloBias
        ╰── NcHaloBiasSTSpher

Description

Object implementation to compute the halo bias function given the Sheth-Tormen mass function for spherical collapse. A description of the function is given below. Check nc_halo_bias.c for a description of halo biases and nc_multiplicity_func_st.c for the Sheth-Tormen mass function.

The Sheth-Tormen bias can be obtained in the same way as the Press-Schechter bias by performing a perturbative expansion in the mass function around the background density contrast. This bias has a significant impact on less massive halos, and for a spherical collapse is given by \begin{align} b(\nu)=1+\frac{a \nu^2-1}{\delta_c}+\frac{2 p}{\delta_c\left[1+\left(a_c \nu^2\right)^p\right]} \end{align} where $b(\nu)$ is the bias, $\delta_c$ is the critical threshold, $\nu = \frac{\delta_c}{\sigma}$, and $(a, p)$ are free parameters determined by the number of massive halos in the simulations and by the shape of the mass function at the low-mass end, respectively.

The user must provide input the values: NcHaloMassFunction , delta_c , a , p - nc_halo_bias_st_spher_new_full().

Functions

nc_halo_bias_st_spher_new ()

NcHaloBiasSTSpher *
nc_halo_bias_st_spher_new (NcHaloMassFunction *mfp);

Creates a new NcHaloBiasSTSpher object with undefined parameters.

[constructor]

Parameters

Returns

A new NcHaloBias.


nc_halo_bias_st_spher_new_full ()

NcHaloBiasSTSpher *
nc_halo_bias_st_spher_new_full (NcHaloMassFunction *mfp,
                                gdouble delta_c,
                                gdouble a,
                                gdouble p);

Creates a new NcHaloBiasSTSpher object with the input values.

Parameters

mfp

a NcHaloMassFunction

 

delta_c

Density contrast critical threshold

 

a

Bias function parameter

 

p

Bias function parameter

 

Returns

A new NcHaloBias.


nc_halo_bias_st_spher_set_delta_c ()

void
nc_halo_bias_st_spher_set_delta_c (NcHaloBiasSTSpher *biasf_st_spher,
                                   gdouble delta_c);

Sets the value delta_c to the “critical-delta” property.

Parameters

biasf_st_spher

a NcHaloBiasSTSpher.

 

delta_c

value of “critical-delta”.

 

nc_halo_bias_st_spher_get_delta_c ()

gdouble
nc_halo_bias_st_spher_get_delta_c (const NcHaloBiasSTSpher *biasf_st_spher);

Parameters

biasf_st_spher

a NcHaloBiasSTSpher.

 

Returns

the value of “critical_delta” property.


nc_halo_bias_st_spher_set_a ()

void
nc_halo_bias_st_spher_set_a (NcHaloBiasSTSpher *biasf_st_spher,
                             gdouble a);

Sets the value a to the “a” property.

Parameters

biasf_st_spher

a NcHaloBiasSTSpher.

 

a

value of “a”.

 

nc_halo_bias_st_spher_get_a ()

gdouble
nc_halo_bias_st_spher_get_a (const NcHaloBiasSTSpher *biasf_st_spher);

Parameters

biasf_st_spher

a NcHaloBiasSTSpher.

 

Returns

the value of “a” property.


nc_halo_bias_st_spher_set_p ()

void
nc_halo_bias_st_spher_set_p (NcHaloBiasSTSpher *biasf_st_spher,
                             gdouble p);

Sets the value p to the “p” property.

Parameters

biasf_st_spher

a NcHaloBiasSTSpher.

 

p

value of “p”.

 

nc_halo_bias_st_spher_get_p ()

gdouble
nc_halo_bias_st_spher_get_p (const NcHaloBiasSTSpher *biasf_st_spher);

Parameters

biasf_st_spher

a NcHaloBiasSTSpher.

 

Returns

the value of “p” property.

Property Details

The “a” property

  “a”                        double

Bias parameter determined by the number of massive halos in the simulations. (check limits values)

Owner: NcHaloBiasSTSpher

Flags: Read / Write / Construct Only

Allowed values: >= 0

Default value: 0.75


The “critical-delta” property

  “critical-delta”           double

Critical delta.

Owner: NcHaloBiasSTSpher

Flags: Read / Write / Construct Only

Allowed values: >= 0

Default value: 1.686


The “p” property

  “p”                        double

Bias parameter determined by the shape of the mass function at the low-mass end. (check limits values)

Owner: NcHaloBiasSTSpher

Flags: Read / Write / Construct Only

Allowed values: >= 0

Default value: 0.3