make.exponential.apertures: Make Exponential Profile Stamps

In AngusWright/LAMBDAR: Measure galaxy fluxes from an arbitrary FITS image using input aperture locations and dimensions

Make Exponential Profile Stamps

Description

__This function is not designed to be called directly, but rather is an internal function to create.sim__

Create a length (m) list of (n,n) arrays, containing exponential profiles determined by the input aperture parameters. The exponential profiles are constructed assuming that the input apertures are 2.5*Kron apertures, such as those output by SExtractor. Using these parameters, the function then creates realistic exponential profiles using a Monte Carlo integration of simulated photon counts on a per-object basis. In this way, the simulation correctly models the central region of the exponential profile, while simultaneously generating realistic shot-noise variations. Objects that are supplied with zero width (ie. point sources) are simulated as perfect gaussians.

Usage

make.exponential.apertures(outenv = parent.env(environment()),
env = NULL, ObsParm, padGals, col.corr = 0, confuse = FALSE)
rotate.data.2d(x,y,theta,about.centre=FALSE)
make.rotation.matrix.2d(theta)

Arguments

env	environment; the environment containing the parameters used in ‘measure.fluxes’
outenv	environment; the environment where the returned values are to be stored. If not provided, outenv defaults to the input env.
ObsParm	List containing Observation Parameters needed in creating simulated galaxies; Exposure Time (sec; exp=), Collecting Area (meters squared; area=), Effective wavelength of filter (Angstrom; lamEff=), and Effective width of filter (Angstrom; WEff=). For example, SDSS r-band has parameters ObsParm=list(exp=53.9, area=4.91, lamEff=1111.2, Weff=6165).
padGals	logical; if TRUE then the simulated image will have galaxies added beyond those in the input catalogue, such that the galactic number counts follow the power law log(N)=-0.01476*m_r^2+1.025*m_r-11.76.
col.corr	numeric; The colour correction need to convert SDSS r-band magnitude to magnitude in the band being analysed. This is needed when padding galaxies because our power law is defined in the r-band. Naturally, this is a 0th order correction, and should be noted when determining the accuracy of simulations that are well beyond the SDSS r-band.
confuse	logical; do you want to confuse the simulation such that the source density is greater than 1 object per FWHM^2
x	numeric vector; x-values to rotate. Used in profile generation.
y	numeric vector; y-values to rotate. Used in profile generation.
theta	numeric; theta (in N90E0) for matrix rotation. Used in profile generation.
about.centre	logical; do you want the rotation to happen around the centre of the matrix, rather than the corner?

Value

numeric [[m]][n,n] list; stamps containing exponential profiles of simulated galaxies

Author(s)

Angus H Wright ICRAR [e-mail]

See Also

measure.fluxes, flux.measurements

AngusWright/LAMBDAR documentation built on Sept. 19, 2024, 10:26 a.m.