Groups of igmspec

This document describes the data groups of igmspec.

List of Surveys

Below is the list of data groups included in igmspec v03:

• BOSS DR14 Dataset [BOSS_DR14]
• COS-Dwarfs Dataset [COS-Dwarfs]
• COS-Halos Dataset [COS-Halos]
• ESI_DLA Dataset [ESI_DLA]
• GGG Dataset [GGG]
• HDLA100 Dataset [HDLA100]
• HD-LLS Dataset [HD-LLS_DR1]
• HST_z2 Dataset [HST_z2]
• HSTQSO Dataset [HSTQSO]
• KODIAQ Dataset [KODIAQ_DR1]
• KODIAQ Dataset [KODIAQ_DR2]
• MUSoDLA Dataset [MUSoDLA]
• XQ-100 Dataset [XQ-100]
• SDSS Dataset [SDSS_DR7]
• UVES_Dall Dataset [UVES_Dall]
• UVpSM4 Dataset [UVpSM4]
• 2QZ Dataset [2QZ]
• ESI z~6 Dataset [ESI_z6]
• UVES SQUAD [SQUAD_DR1]

Each document provides the survey reference and additional details on the spectra and associated meta data.

Here is the list of data groups in v02 that are not included in v03 because they are superseded by v03:

• BOSS DR12 Dataset [BOSS_DR12]

Overview

Each group included in igmspec is composed of two components:

1. A Table of meta data
2. A numpy data array containing the spectra

Meta Data

Each group has its own unique set of meta data describing the data products. The following keys are required for inclusion in igmspec:

Key	Type	Description
IGM_ID	int	Unique igmspec identifier
zem_GROUP	float	Emission redshift of background source given by the survey
RA_GROUP	float	Right Ascension (deg) given by the survey
DEC_GROUP	float	Declination (deg) given by the survey
EPOCH	float	Coordinate epoch (only 2000 in igmspec v1.0)
DATE-OBS	str	Date observed (YYYY-MM-DD)
R	float	Instrument resolution, \(\lambda/\Delta\lambda\) (FWHM)
WV_MIN	float	Minimum wavelength of the spectrum
WV_MAX	float	Maximum wavelength of the spectrum
NPIX	int	Number of pixels in the spectrum; may include null values
GROUP_ID	int	Unique identifier for the group [not well implemented yet]
SPEC_FILE	str	Spectrum file name
INSTR	str	Instrument file name (see instr-and-disp for definitions)
DISPERSER	str	Disperser name (see instr-and-disp for definitions)
TELESCOPE	str	Telescope name (see Telescopes below for definitions)

Additional meta data may be provided for individual surveys.

Instruments and Dispersers

The complete list of instruments and associated dispersers that may be used in igmspec are provided in the specdb documentation.

Telescopes

Similarly, the list of telescopes that may be used in igmspec are provided in the specdb documentation.

Spectral Data

The spectra in igmspec are written as a numpy masked array with three required columns and one optional:

Key	Type	Description
wave	float64	Wavelength array; default is Angstroms
flux	float32	Flux array; default is unitless
sig	float32	Error array; same units as flux
co (optional)	float32	Continuum array; same units as flux

The software included with specdb read these data into a XSpectrum1D object in the linetools software repository.