The Slitless Spectroscopy Data Extraction Software aXe

TL;DR

The paper describes aXe, a software package for extracting slitless spectra from Hubble Space Telescope data, addressing challenges like spectral overlap and contamination, and introducing new methods for data rebinning and correction.

Contribution

The paper introduces aXe, a comprehensive software tool for slitless spectroscopy data reduction, including novel methods for spectral extraction, contamination assessment, and spectral data co-adding.

Findings

Effective spectral overlap handling and contamination assessment.

Implementation of aXedrizzle for improved spectral data co-adding.

Correction techniques for detector fringing in ACS CCD spectra.

Abstract

The methods and techniques for the slitless spectroscopy software aXe, which was designed to reduce data from the various slitless spectroscopy modes of Hubble Space Telescope instruments, are described. aXe can treat slitless spectra from different instruments such as ACS, NICMOS and WFC3 through the use of a configuration file which contains all the instrument dependent parameters. The basis of the spectral extraction within aXe are the position, morphology and photometry of the objects on a companion direct image. Several aspects of slitless spectroscopy, such as the overlap of spectra, an extraction dependent on object shape and the provision of flat-field cubes, motivate a dedicated software package, and the solutions offered within aXe are discussed in detail. The effect of the mutual contamination of spectra can be quantitatively assessed in aXe, using spectral and morphological information from the companion direct image(s). A new method named 'aXedrizzle' for 2D rebinning and co-adding spectral data, taken with small shifts or dithers, is described. The extraction of slitless spectra with optimal weighting is outlined and the correction of spectra for detector fringing for the ACS CCD's is presented. Auxiliary software for simulating slitless data and for visualizing the results of an aXe extraction is outlined.