The Slitless Spectroscopy Data Extraction Software aXe

By M. Kummel, Jeremy R. Walsh, N. Pirzkal, H. Kuntschner, A. Pasquali. 2008

143 citations recorded by the source corpus.

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 that 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 CCDs is presented. Auxiliary software for simulating slitless data and for visualizing the results of an aXe extraction is outlined.

Subfields: Electrical and Electronic Engineering, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/fb2d8078801e058183963cdcf17da0afe6e84860

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In Electrical and Electronic Engineering

1. P. Oesch
2. G. Illingworth
3. M. Franx
4. I. Labbé
5. P. V. van Dokkum
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In Instrumentation

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In Statistical and Nonlinear Physics

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Citations in the corpus

• 3D-HST WFC3-SELECTED PHOTOMETRIC CATALOGS IN THE FIVE CANDELS/3D-HST FIELDS: PHOTOMETRY, PHOTOMETRIC REDSHIFTS, AND STELLAR MASSES (2014, methodology): “In addition to the grism exposures we obtain direct images in broad band filters, as required for wavelength calibration of the spectra and for associating spectra with objects (Kümmel et al. 2009).”
• THE CHANDRA COSMOS SURVEY. III. OPTICAL AND INFRARED IDENTIFICATION OF X-RAY POINT SOURCES (2012, methodology): “The dispersed data (G141 grism) were reduced using theaXe slitless spectroscopy package Kummel et al. (2009).”
• 3D-HST: A WIDE-FIELD GRISM SPECTROSCOPIC SURVEY WITH THE HUBBLE SPACE TELESCOPE (2012, methodology): “…includes an option to account for the orientation of this effective slit to optimize the wavelength resolution of the extracted spectra (see Kümmel et al. 2009); however, we simply adopt the spatial axis as perpendicular to the spectral trace and account for the orientation and shape of…”
• THE 3D-HST SURVEY: HUBBLE SPACE TELESCOPE WFC3/G141 GRISM SPECTRA, REDSHIFTS, AND EMISSION LINE MEASUREMENTS FOR ∼100,000 GALAXIES (2015, methodology): “At that time, the pipeline used custom pre-processing steps such as alignment, flat-fielding and sky-subtraction followed by extraction of the grism spectra using the aXe software package (Kümmel et al. 2009).”
• THE FLAT TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ1214b FROM WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE (2011, methodology): “The Python/PyRAF software package aXe was developed to extract spectra from slitless grism observations with WFC3 and other Hubble instruments (Kümmel et al. 2009), but it is optimized for extracting large numbers of spectra from full frame dithered grism images.”
• VERY STRONG EMISSION-LINE GALAXIES IN THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY AND IMPLICATIONS FOR HIGH-REDSHIFT GALAXIES, (2011, methodology): “Then, the slitless extraction package aXe 2.0 (Kümmel et al. 2009) is used for the spectral extraction.”