mkpsfmap

Synopsis

Look up the radius of the PSF for each pixel in an image

Syntax

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

Description

mkpsfmap takes an input image and looks up the radius of the PSF (under the approximation of a circular PSF) 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.

Examples

Example 1

mkpsfmap acis_img.fits acis_psf.fits 1.4 ecf=0.5

Computes the radius of the psf 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 ecf=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).

Example 3

mkpsfmap acis_img.fits acis_psfmap.fits energy=INDEF spectrum=wghts.dat
ecf=0.9

When energy=INDEF, the spectrum file is used. The output will be computed at the spectrum energies and weighted by the weights.

Parameters

name	type	ftype	def	min	max	units	reqd
infile	file	input					yes
outfile	file	output					yes
energy	real					keV	yes
spectrum	file						yes
ecf	real			0	1		yes
psffile	file	input	CALDB				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.

If the value is set to INDEF, then the spectrum will be use.

Parameter=spectrum (file required)

Spectral weights file

If a spectrum is input (two column file with energy (keV) vs. weights (renormlized to sum(weights)=1) then a spectrally weighted PSF map will be created.

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 default=CALDB)

The PSF calibration file.

Parameter=units (string not required default=arcsec)

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

Parameter=geompar (file not required filetype=input)

The pixlib geometry file name.

Parameter=clobber (boolean not required default=no)

Overwrite existing output dataset with same name?

Changes in CIAO 4.15

Updated the tool to recognize real-valued NULLs and to recognize valid data ranges.

Bugs

There are no known bugs for this tool.