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Last modified: December 2009

AHELP for CIAO 4.2


Context: tools


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


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


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% enclosed counts fraction

Example 2

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

Computes the 90% 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).


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 the data-subspace.

Parameter=energy (real required units=keV)

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

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?


See the bugs page for this tool on the CIAO website for an up-to-date listing of known bugs.

See Also

acis_bkgrnd_lookup, acis_fef_lookup, acis_set_ardlib, acisspec, add_grating_orders, add_grating_spectra, asphist, dither_region, dmarfadd, dmextract, eff2evt, fullgarf, hrc_bkgrnd_lookup, make_instmap_weights, merge_all, mkacisrmf, mkarf, mkexpmap, mkgarf, mkgrmf, mkinstmap, mkpsf, mkrmf, mkwarf, psextract, psf_project_ray, rmfimg, specextract

Last modified: December 2009