mkpsfmap

Context: tools

Synopsis

Look up the PSF-size for each pixel in an image

Syntax

mkpsfmap  infile outfile energy ecf [psffile] [units] [geompar]
[clobber]

Description

mkpsfmap takes an input image and looks up the PSF-size at each pixel in the image. The user supplies the energy and the desired Enclosed Counts Fraction (ECF) value.

Any NULL, NaN or pixels outside the data subspace are set to NaN. This is useful, for instance, to be able to filter the image with the field-of-view file ("ahelp skyfov") so that only pixels which are on the chip will get resolved.

Note that this tool does not take the average aspect dy, dz, and dtheta into account.

Example 1

mkpsfmap acis_img.fits acis_psf.fits 1.4 0.5

Computes the psf-size for each pixel in the input image at 1.4 keV for a 50% (0.5) enclosed counts fraction

Example 2

mkpsfmap "hrc_img.fits[sky=region(fov.fits)]" psf.fits 0.9 0.9
units=physical

Computes the 90% (0.9) ECF at 0.9 keV at each pixel in the input. Pixels that fall outside the supplied fov.fits region are set to NaN. The output units are in physical pixel (as opposed to the default which is the psfsize in arcsec).

Parameters

name	type	ftype	def	min	max	units	reqd
infile	file	input					yes
outfile	file	output					yes
energy	real					keV	yes
ecf	real			0	1		yes
psffile	file	input					no
units	string		arcsec				no
geompar	file	input					no
clobber	boolean		no				no

Detailed Parameter Descriptions

Parameter=infile `(file required filetype=input)`

Input image

The header must contain the SIM_* and RA/DEC/ROLL_ PNT (or _NOM) keywords.

Parameter=outfile `(file required filetype=output)`

Output image

The units of the pixel values in the output image are controled by the 'units' parameter. NaN values indicate that the input image was NaN, NULL, or outside of the data subspace.

Parameter=energy `(real required units=keV)`

Energy of the PSF to lookup in keV.

Parameter=ecf `(real required min=0 max=1)`

The encircled counts fraction (ECF). Value is between 0 and 1 (100%).

Parameter=psffile `(file not required filetype=input)`

Parameter=units `(string not required default=arcsec)`

Valid units are "logical", "physical", or "arcsec"

Parameter=geompar `(file not required filetype=input)`

Parameter=clobber `(boolean not required default=no)`

Overwrite existing output dataset with same name?

Changes in CIAO 4.4

The tool has been updated to work correctly on reprojected data. Previously, mkpsfmap assumed that _NOM and _PNT header values were the same when calculating the offsets, which is not the case for reprojected data.

Bugs

There are no known bugs for this tool.

mkpsfmap

Parameter=infile (file required filetype=input)

Parameter=outfile (file required filetype=output)

Parameter=energy (real required units=keV)

Parameter=ecf (real required min=0 max=1)

Parameter=psffile (file not required filetype=input)

Parameter=units (string not required default=arcsec)

Parameter=geompar (file not required filetype=input)

Parameter=clobber (boolean not required default=no)