Light Profiles

This section covers the light profiles implemented in GLEE for modelling the surface brightness of lensing galaxies and lensed arcs.

General Remarks

Light profiles are used in the esource_light block of the GLEE configfile to model the observed intensity distribution of sources in the image plane. Each profile describes the 2D surface brightness $I(x, y)$ of a component, which is then convolved with the PSF before comparison to data.

Common parameters shared by most profiles:

Parameter	Description
x1c	x-coordinate of the centroid (arcsec)
x2c	y-coordinate of the centroid (arcsec)
q	Axis ratio $b/a$ (minor/major), range $(0, 1]$
pa	Position angle in radians, counter-clockwise from the +x axis
Amp	Amplitude (peak surface brightness or normalisation)

:::note Units All spatial coordinates and radii are in arcseconds. Surface brightness values are in counts per arcsecond² (or counts per pixel, depending on configuration). :::

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Below is a list of all detailed profile documentation:

Gaussian Light Profile

Elliptical 2D Gaussian light profile for modelling compact sources.

Moffat Light Profile

Elliptical Moffat light profile, commonly used for PSF modelling.

Sérsic Light Profile

Elliptical Sérsic light profile — the standard model for galaxy surface brightness.

Point Spread Function (PSF)

PSF light profile — used to model point sources such as quasars in the image plane.

PIEMD (Light)

Pseudo-Isothermal Elliptical Mass Distribution used as a light profile.