pileup_map

Synopsis

Compute image that gives indication of pileup.

pileup_map  infile outfile [clobber] [verbose]

Description

The pileup_map tool computes a rough estimate of the amount of pileup. The output image is the number of counts per ACIS frame. The following table is used to convert from these image values to an estimated pileup fraction.

Note that the "Count rate per sec" column assumes a standard frame time of 3.2 s. These numbers are meant only to serve as a guide.

Relationship between Pileup Fraction and Count Rate

In a severely piled-up case, the counts image can form a 'crater' where the apparent pileup is low. There should be a halo around this crater with a larger pileup indicator.

Details on how the tool works are available in the Pile-up Fractions and Count Rates document [PDF].

Example

pileup_map img.fits pileup.fits

Creates the pileup image based on the input img.fits file.

Parameters

Detailed Parameter Descriptions

Parameter=infile (file required filetype=input)

Input counts image

The input image must be binned by 1 for the algorithm to work. The recommended image size is ~2048x2048. The file should not have any energy cuts applied, just the standard grade and status filtering.

It is recommended also that the tool be run on a chip-by-chip basis, to avoid incorrect results for cases where the observation experienced a number of dropped frames, as is often the case where pileup is a concern. Users may use the sky FOV file to create an image of the desired chip, e.g.

dmcopy "evt2.fits[ccd_id=3,sky=region(fov.fits)][bin sky=::1]" img.fits

See "ahelp skyfov" for more information.

Parameter=outfile (file required filetype=output)

The output image

The output image has units of counts/frame.

Parameter=clobber (boolean default=no)

Clobber outfile

Remove outfile if it already exists?

Parameter=verbose (integer default=0 min=0 max=5)

The tool chatter level

Verbose can be from 0 to 5, generating different amounts of debugging output.

Changes in CIAO 4.5

• The output units are recorded in the file header.

Bugs

Tool does not add a history entry to the header.

The tool does not add a history entry to the output file header, which means the dmhistory tool cannot be used to recall the command.

See Also

dm

dmfiltering

tools

dmappend, dmcontour, dmellipse, dmfilth, dmimg2jpg, dmimgadapt, dmimgblob, dmimgcalc, dmimgdist, dmimgfilt, dmimghist, dmimghull, dmimglasso, dmimgpick, dmimgpm, dmimgproject, dmimgreproject, dmimgthresh, dmmaskbin, dmmaskfill, dmnautilus, dmregrid, dmregrid2, dmstat, evalpos, get_fov_limits, get_sky_limits, imgmoment, mean_energy_map