Datamodel: BOSSLyaDR9_cat

General Description

This catalog lists objects in the DR9 Lyman-alpha Forest Sample, that are suitable for Lyman-alpha forest analysis. This is a greatly simplified sub-sample of the DR9 Quasar Catalog, with the fields SNR, SNR_LYAF, CHISQ_CONT, CONT_FLAG, CONT_TEMPLATE, Z_DLA, and Z_DLA added. Each object in the catalog has a corresponding speclya file.

This documentation describes the FITS format file BOSSLyaDR9_cat.fits; there is also an ASCII version BOSSLyaDR9_cat.txt with the same columns in the same order as described below.

Naming Convention
BOSSLyaDR9_cat\.(fits|txt)
Approximate Size
4 MB
File Type
FITS or ASCII

HDU0: Null extension

This is a null header created by IDL MWRFITS.

HDU1: BOSSLyaDR9_cat Catalog

EXTNAME="BOSSLyaDR9_cat" with a binary FITS table containing the following columns:

Required Data Table Columns
NameTypeUnitsDescription
SDSS_NAMEchar[18]- SDSS-DR9 designation
RAfloat32deg RA (J2000)
DECfloat32deg DEC (J2000)
THING_IDint32- Unique identifier
PLATEint32- Plate number
MJDint32- Spectroscopic MJD
FIBERIDint32- Fiber number
Z_VIfloat32- Visual inspection redshift from DR9Q
Z_PIPEfloat32- BOSS pipeline redshift
SNRfloat32- Median signal-to-noise ratio (1268-1380A rest)
SNR_LYAFfloat32- Median signal-to-noise ratio (1041-1185A rest)
CHISQ_CONTfloat32- Reduced chi-squared of continuum fit
CONT_FLAGint32- Continuum visual inspection flag
CONT_TEMPLATEchar[8]- Quasar template used
Z_DLAfloat32- DLA absorption redshift. Set to -1 in objects without DLAs.
LOG_NHIfloat32- DLA HI column density, log10(N_HI [cm^-2]). Set to -1 in objects without DLAs.