source.subtraction: Source Subtraction from FITS image

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

Source Subtraction from FITS image

Description

__This function is not designed to be called directly, but rather is an internal function to measure.fluxes__

Perform a subtraction of sources and/or contaminants from a FITS image.

Usage

source.subtraction(image, sfa_models, ap.lims.data.stamp,
fluxes, outputfile, outputheader, beamarea, inside.mask,
diagnostic = FALSE, verbose = FALSE, fluxmap.outputfile = "fluxmap.fits")

Arguments

image	numeric (j,k) array; the image to be used for subtraction
sfa_models	numeric length (m) list of (n,n) arrays; length (m) list of (n,n) stamps containing the apertures to be subtracted
ap.lims.data.stamp	numeric (m,4) array; limits of where the aperture stamps are to be placed, in image pixel space; [,1]=x_lo, [,2]=x_up, [,3]=y_lo, [,4]=y_up.
fluxes	numeric (m) vector; flux weights used in normalisation of apertures
outputfile	string; relative path to, and filename of, the output subtracted image
outputheader	list; the FITS header for the output image
beamarea	numeric; the beam area for the input image
inside.mask	logical (m) vector; if TRUE, then the object will be subtracted
diagnostic	logical; if TRUE, then perform diagnostic checks and outputs
verbose	logical; if TRUE, then perform verbose outputs
fluxmap.outputfile	string; relative path to, and filename of, the output fluxmap image

Details

Procedure performs a subtraction of the provided sfa_models from ‘image’. The models are normalised so that the integral of the ith model is fluxes[i]. This means that the source subtraction is only going to accurately remove all object flux (leaving only noise) in cases where the object is perfectly modeled. As this is rarely the case, the result of this source subtraction is generally the creation of ‘butterfly’ patterns. This is an indication that objects are not being modeled perfectly by the aperture-psf convolution.

Value

NULL; all output is to file

Author(s)

Angus H Wright ICRAR [e-mail]

See Also

measure.fluxes, flux.measurements

AngusWright/LAMBDAR documentation built on May 12, 2022, 1:49 a.m.