CLASSY Data Products and File Extensions
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Co-added spectra (_co-added.fits)
CLASSY Spectra are stored as multi-extension fits (MEF) files. The current CLASSY files have 21 extensions (or less, depending on gratings included)): one primary header and 15 extensions of data tables. Spectral data tables are included for three dataset types:
- G130M: This is the highest resolution dataset, consisting of co-added G130M grating spectra only, with a resolution* of 0.060 Å/resel (6 pixels) or 14.77 km s-1/resel at LyA λ1215.
- HR: This is the high resolution dataset, consisting of co-added G130M+G160M grating spectra, with a resolution* of 0.073 Å/resel (6 pixels) or 14.20 km s-1/resel at CIV λ1550.
- MR: This is the moderate resolution dataset, consisting of co-added G130M+G160M+G185M grating spectra, with a resolution* of 0.222 Å/resel or 34.89 km s-1/resel at CIII] λ1909.
- LR: Some of the CLASSY targets also have low resolution (LR) G140L spectra, so a fourth LR dataset will be added in the future, with a resolution* of 0.498 Å/resel or 78.3 km s-1/resel at CIII] λ1909.
*The spectral resolutions here are the maximum resolutions for a point source, where actual spectral resolution of an individual galaxy will be less than this depending on the nature of the source profile. Resel here indicates a binning of six native pixels.
Each of the three datasets has the following five data tables and extensions
- OBS DATASET CO-ADDED
- If multiple datasets exist, they are co-added.
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OBS DATASET CO-ADDED + GAL CORR
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Ext 1 spectrum, plus corrected for galactic extinction.
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REST DATASET CO-ADDED + GAL CORR + zCORR
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Ext 2 spectrum, plus redshift corrected.
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OBS DATASET CO-ADDED + GAL CORR + BINNED
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Ext 2 spectrum, plus binned by N pixels, where N is given in the primary header.
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REST DATASET CO-ADDED + GAL CORR + BINNED + zCORR
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Ext 3 spectrum, plus binned by N pixels, where N is given in the primary header.
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Each data table has four columns:
- WAVE in units of Angstroms
- FLUX in units of ×10−15 erg cm−2 s−1 AA−1
- ERROR in units of ×10−15 erg cm−2 s−1 AA−1
- SNR