add_gammat_point_mass

Add point mass contributions to galaxy-galaxy lensing (gamma_t) signal

File	shear/point_mass/add_gammat_point_mass.py
Attribution	Shivam Pandey
URL
Citations	https://doi.org/10.1093/mnras/stz2761

This module adds point mass contributions to the galaxy-galaxy lensing tangential shear signal gamma_t. Point masses around lenses contribute a 1/theta^2 term to the lensing signal.

The module computes the critical surface density inverse (sigma_crit^-1) for each lens-source bin combination and uses bias parameters to scale the point mass contribution. It can use either the cosmological parameters from the pipeline or a fiducial cosmology for distance calculations.

Assumptions

• Point mass contributions follow 1/theta^2 angular dependence

• Critical surface density can be computed from geometry or fiducial cosmology

Setup Parameters

Name	Type	Default	Description
bias_section	str	add_pm	Section name containing point mass bias parameters
bias_prefix	str	b_	Prefix for bias parameter names
add_togammat	bool	False	Whether to add point mass term to existing gamma_t
use_fiducial	bool	False	Whether to use fiducial cosmology for distance calculations
Omega_m_fid	real	0.3	Fiducial matter density parameter
H0_fid	real	69.0	Fiducial Hubble parameter in km/s/Mpc
lens_nz_section	str	nz_lens	Section name for lens n(z) data
source_nz_section	str	nz_source	Section name for source n(z) data
gammat_section	str	galaxy_shear_xi	Section name for gamma_t measurements
sigcrit_inv_section	str	sigma_crit_inv_lens_source	Section name for critical surface density inverse output

Input values

Section	Name	Type	Default	Description
bias_section	bias_parameter	real		Point mass bias parameter for lens bins
lens_nz_section	nbin	int		Number of lens redshift bins
	z	real 1d		Redshift sample values for lenses
	bin_i	real 1d		Lens n(z) for bin i
source_nz_section	nbin	int		Number of source redshift bins
	z	real 1d		Redshift sample values for sources
	bin_i	real 1d		Source n(z) for bin i
gammat_section	theta	real 1d		Angular separation values (if add_togammat=true)
	bin_i_j	real 1d		Galaxy-galaxy lensing signal for lens bin i, source bin j
cosmological_parameters	hubble	real		Hubble parameter H0 in km/s/Mpc (if use_fiducial=false)
	omega_m	real		Matter density parameter (if use_fiducial=false)
distances	z	real 1d		Redshift values for distance measurements (if use_fiducial=false)
	d_m	real 1d		Comoving distance in Mpc (if use_fiducial=false)

Output values

Output values

Section	Name	Type	Description
gammat_section	bin_i_j	real 1d	Modified gamma_t with point mass contribution (if add_togammat=true)
point_mass	bin_i_j	real	Point mass contribution coefficient for lens bin i, source bin j
sigcrit_inv_section	sigma_crit_inv_i_j	real	Critical surface density inverse for lens bin i, source bin j