profoundHotFuzz: Hot Fuzz Fitter

In asgr/ProFound: Photometry Tools

Hot Fuzz Fitter

Description

Functions to fit the tenuous outer fuzz of extended sources.

Usage

profoundHotFuzz(profound = NULL, loc = NULL, box = c(200, 200), region = NULL, size = 21,
  shape = "disc", select = NULL, rough = TRUE, nser = 1, dofit = TRUE, Niters = c(200, 0),
  fitRe = TRUE, axrat = 'profound', ...)
  
profoundPSFFuzz(profound = NULL, loc = NULL, box = c(200,200), size = 21, shape = "disc",
  select = NULL, rough = TRUE, nser = 2, dofit = TRUE, Niters = c(200, 0), ...)

Arguments

profound	List, required; output from profoundProFound.
loc	Numeric vector; two element [x,y] position for cutout region.
box	Numeric vector; two element dimensions of the box to cut out from image centred on loc (in pixels).
region	Boolean matrix; region to use for determining extended fuzzy profiles. If not defined then the dilated outskirts of objects will be defined internally.
size	Integer scalar; the size (e.g. width/diameter) of the dilation kernel in pixels. Should be an odd number else will be rounded up to the nearest odd number.
shape	Character scalar; the shape of the dilation kernel. Options are 'box', 'disc', 'diamond', 'Gaussian', 'line'.
select	Vector; either logical vector of segstat rows to keep (same length as segstats), or integer vector of row numbers.
rough	Logical; should the profile be approximated roughly. Usually setting this to true is fine for the out parts of light profiles.
nser	Numeric scalar; the Sersic index of the profile to use when fitting. When fitting "Hot-Fuzz" the Magnitude, Re and Index become quite degenerate, so this can usually be left at the default of 1 (meaning an exponential/power-law outer profile).
dofit	Logical; should fitting be done (TRUE) or just produce the outputs that can be later fitted (FALSE)?
Niters	Integer vector; if dofit = TRUE, the number of CMA and MCMC steps to make with Highlander.
fitRe	Logical; if dofit = TRUE, should Re also be fitted?
axrat	Character or numeric; either set to 'profound' (so axrat in inherited from ProFound), or set to the desired value.
...	Other arguments to pass to Highlander.

Details

These codes are probably not general user at the moment (although feel free to use them). They were produced with a mind to my (Aaron Robotham's) ARC Future Fellowship project.

In brief they construct a ProFit region map that is defined by the segmentation map from ProFound and a dilation of this (using the provided kernel arguments). This region map becomes the target for a large ProFit model that is in effect only attempting to fit the outer "Hot Fuzz" that is not inside the standard ProFound segmentation map. Because of how far out this fuzz usually easier, a computationally cheaper 'rough' model can usually be used.

Value

profoundHotFuzz fits the outer profile of target galaxies. This is used to model the "Hot Fuzz" in the outer parts of galaxy profiles. It inherits the ellipticity and orientation of the profoundProFound output, allowing variable magnitude and Re by default per source.

profoundPSFFuzz fits the outer profile of target stars. This is used to model the "Hot Fuzz" in the outer parts of star profiles. It assumes the stars are circular, allowing variable Re and Index shared for all sources (so a common PSF profile), and variable magnitude per source (different flux stars).

The either function the output is:

If dofit = TRUE the first list elements are all the usual outputs from Highlander.

Modellist	The best fit modellist (if dofit = TRUE).
image_model	The best fit model image (if dofit = TRUE).
Data	The fitting data for Highlander.
image	The sky subtracted fitting image.
segim	The fitting segmentation map.
segim_redo	The dilated fitting segmentation map.
sigma	The fitting segstats map.
segstats	The fitting segstats.

Author(s)

Aaron Robotham

See Also

profoundProFound, ~~~

Examples

## Not run: 
image = Rfits_read_image(system.file("extdata", 'VIKING/mystery_VIKING_Z.fits',
  package="ProFound"))
profound = profoundProFound(image, magzero=30)

#This takes a few minutes to run
fuzz_fit = profoundHotFuzz(profound)

magimage(fuzz_fit$image, qdiff=TRUE)

no_fuzz = fuzz_fit$image
sel = profound$segim_orig == 0
no_fuzz[sel] = no_fuzz[sel] - fuzz_fit$image_model[sel] 

magimage(no_fuzz, qdiff=TRUE)

## End(Not run)

asgr/ProFound documentation built on Feb. 10, 2024, 9:04 p.m.