aXe Reduction Methodology in a Nutshell
The aXe reduction tasks enable automated, efficient extraction of thousands of spectra from slitless spectral images. The software drives the spectral extraction based on two sets of information:
- a catalogue of objects in the field, and
- configuration files which calibrate the positioning of the spectra and the wavelength dispersion solution, and convert from extracted detector units to physical flux units.
aXe is not instrument specific, and can accommodate data from different instrument/grism combinations by specifying the required parameters in the configuration file.
aXe is PyRAF/IRAF software which is comprised of several tasks and is distributed as a subpackage of the Space Telescope Data Analysis System (STSDAS) under analysis.slitless.axe. New releases of STSDAS become available approximately twice a year. More frequent updates and bug fixes are available in IRAFX, the development version of STSDAS, which is released weekly.
Download and installation information for the STSDAS package can be found at STSDAS Home, and for IRAFX at http://stsdas.stsci.edu/irafx.
Detailed notes on aXe releases and bugs can be found here.
Support of processing with AstroDrizzled products is currently provided only in versions of aXe in IRAFX with release dates after 2013-03-28.
- WFC3/IR Grism Cookbook – Short step-by-step guide to reducing G141 (IR) grism data using aXe. Includes link to download Grism data from the WFC3 ERS Program, which is used as an example in the guide.
- aXe User Manual – Provides detailed documentation on all tasks and parameter settings in aXe, including more sophisticated reduction options not discussed in the WFC3/IR Grism Cookbook.
- aXe PASP Paper – Overview of aXe methodology (Kummel et al. 2009).
- aXedrizzle Overview – Description of procedure for the co-addition of the 2D spectra. Not to be confused with Astrodrizzle which is for the co-addition of direct imaging data.
The WFC3 IR grism cookbook has been updated to accurately reflect availability of AstroDrizzle support in IRAFX.