- aXe-1.71 was released in April 2009 as the external PyRAF/IRAF package taxe17. It removes some critical
bugs from version 1.70. We strongly recommended to install and use aXe-1.71 for the reduction of all ACS slitless modes.
This latest version of aXe will be integrated into STSDAS version 3.10, which is projected for May 2009.
- aXe-1.70 is part of STSDAS 3.9, which was released in November 2008.
Within STSDAS 3.9, aXe resides in the sub-package 'slitless.axe'.
The new aXe version 1.7 introduces new data reduction techniques that had been developed and applied within the
HLA activities at the ST-ECF to reduce NICMOS G141 and ACS/WFC G800L data. They are described
in the NICMOS HLA data paper and the aXe manual.
The main features of aXe-1.7 are:
- virtual slits: aXe offers to extract the object spectra using a virtual
slit which is optimized to maintain the spectral resolution in the extraction.
In contrast to previous aXe releases, the orientation of the virtual slit and hence the extraction direction
does not coincide with the major or minor axes of the objects.
- smoothed flux conversion: before converting the extracted spectra of extended sources
to physical units (erg/cm^2/s/Angrstom), aXe-1.7 applies a Gaussian smoothing to
the sensitivity function in order to adjust for the degraded spectra resolution. The smoothing kernel
is proportional to the object size in the dispersion direction.
- lower limit for object sizes: aXe-1.7 allows to specify in the configuration file
the size of point-like objects, which acts as a lower limit. Smaller objects are extracted
perpendicular to the trace, using the lower limit to compute the extraction width.
Maintained by Martin Kümmel <mkuemmel@eso.org>
