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Last modified: September 2016

URL: http://cxc.harvard.edu/ciao/ahelp/dax.html
AHELP for CIAO 4.9

dax

Context: tools

Synopsis

Run CIAO tasks from the ds9 Analysis menu

Description

A number of common CIAO tasks are available from the ds9 Analysis menu. This menu addition allows users to get source counts, smooth an image, and create a histogram - among many other things - from the ds9 program in CIAO. The analysis menu tasks are known as "dax" (ds9 analysis extensions).

Getting Started

The commands are stored in the file $ASCDS_INSTALL/contrib/config/ciao.ds9 and are automatically loaded when ds9 is launched within CIAO.

The user can also explicitly point to the file in the ds9 -analysis switch:

unix% ds9 -analysis $ASCDS_INSTALL/contrib/config/ciao.ds9 ...
      

Using the Tools

Under ds9's Analysis menu, at the bottom will be a "CIAO" option. Selecting "CIAO" will display the category of CIAO tasks :

  • Statistics: use the any defined regions to calculate counts, centroid, min, max, etc. Also includes a 'snap-to-centroid' function.
  • Histograms: create spectra, lightcurves, and radial profiles, for example.
  • Coords: use the ds9 crosshair to map coordinates from image to chip, detector, off-axis angles, etc. (Switch to the crosshair cursor in the Edit menu.)
  • Detect: run source detection tools on images.
  • Regions: generate regions that enclose a fraction of flux, magic-wand style source selector (local contouring).
  • Sherpa: extract and fit spectra or fit 2D image.
  • Image Processing: adaptive smooth (including csmooth), adaptive bin, smooth (various kernels), non-linear filtering (median), fill in where sources have been removed (dmfilth), and more options.

Calculating the Statistics

The options under the Statistics item use the combination of all defined regions to calculate the quantities. To exclude certain areas, define a region and use the "Region -> Properties" menu to set it to "exclude". If no regions are defined, the calculations are run on a 1024 x 1024 image created at the current binning value.

Plotting

A ChIPS server is started in the background when ds9 is launched; this ChIPS session is then used for any plotting. If ChIPS is not available, dax uses BLT to plot instead; the user will see an informational message in the terminal in this case.

Note that if you are have loaded the CIAO analysis file manually, you will also need to

source $ASCDS_INSTALL/contrib/config/chips_startup.tk

from the command line before starting ds9.

Modifying and Saving the Plots

To modify a ChIPS plot, first connect to the ChIPS server with the connect() command. Then any ChIPS commands may be used to change the appearance of the plot; more information is available on the ChIPS website.

Once connected to the server, the plot may be saved with the make_script() command.

Known Limitations

  • ds9 uses the funtools syntax to specify filters (spatial, energy) and block names. dax does not convert this filter information to the CIAO format; users should do so to use the filters in CIAO analysis.
  • The stacked shapes (panda, annulus, elliptical annulus, box annulus, etc.) only work with the radial profile task.

Change in the 4.8.4 (September 2016) release

Several tasks have been updated to ensure that the desired region format is retrieved from ds9 instead of relying on the assumed defaults.

Changes in the 4.6.7 (November 2014) release

A new "Net Counts" option has been added that emulates the FUNTOOLs 'Counts in a region' functionality. This provides net counts and rates individually for each region.

The Aperture Photometry task has been renamed and moved. It is now available as the "Statistics -> Photometry (srcflux)" task.

The "All" statistics have been renamed "dmstat" to make it more clear which task is being run.

Bugs

See the CIAO website for an up-to-date listing of known bugs.

Refer to the CIAO bug pages for an up-to-date listing of known issues.


Last modified: September 2016
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