zall-pix-SPECPROD.fits

Summary:

Concatenation of all zpix-*.fits files, combining core redshift and targeting columns across all SURVEYs and PROGRAMs.

Naming Convention:

zcatalog/v2/zall/zall-pix-{SPECPROD}.fits, where {SPECPROD} is the official name of the full reduction, e.g. iron.

Regex:

zall-pix-[a-z0-9][a-z0-9_-]*(?<!-imaging)(?<!-extra)\.fits

File Type:

FITS, ~5 GB

This file contains a concatenation of all input zpix-*.fits core files, combining redshift catalog entries across SURVEYs and PROGRAMs. It adds SURVEY and PROGRAM columns identifying each entry’s origin, and adds SV_PRIMARY/SV_NSPEC for the best SV spectrum and MAIN_PRIMARY/MAIN_NSPEC for the best Main Survey spectrum when the same TARGETID appears in multiple surveys.

The companion zall-pix-SPECPROD-imaging.fits and zall-pix-SPECPROD-extra.fits files contain the imaging photometry and extra columns respectively, row-matched to this file.

Contents

Number	EXTNAME	Type	Contents
HDU0	PRIMARY	IMAGE	Empty
HDU1	ZCATALOG	BINTABLE	Core redshift catalog across all surveys and programs

FITS Header Units

HDU0

EXTNAME = PRIMARY

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
CHECKSUM	9aaGCVYE9aaECUYE	str	HDU checksum
DATASUM	0	str	data unit checksum
ZCATVER	v2	str	Version of zcatalog files

Empty HDU.

HDU1

EXTNAME = ZCATALOG

Core redshift and targeting columns stacked from all zpix-SURVEY-PROGRAM.fits files.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	276	int	width of table in bytes
NAXIS2	3000000	int	number of rows in table
CHECKSUM	QA6lQ26iQ96iQ96i	str	HDU checksum
DATASUM	4284326946	str	data unit checksum
ZCATVER	v2	str	Version of zcatalog files

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique DESI target ID
SURVEY	char[7]		Survey name
PROGRAM	char[6]		DESI program type - BRIGHT, DARK, BACKUP, OTHER
UNIQPIX [1]	int32		Unique HEALPixel identifier encoding both pixel number and NSIDE (DR3+); HEALPIX and NSIDE are in the companion extra file
HEALPIX [1]	int32		HEALPixel containing this location at NSIDE=64 in the NESTED scheme (DR2 only)
Z_BEST	float64		Best redshift: equals Z (Redrock) for most targets, Z_QSO (QuasarNET) for confirmed QSOs where the two differ by >1000 km/s
Z_CONF	uint8		Redshift confidence: 0=no confidence, 1=low confidence (ZWARN==0), 3=high confidence (passes LSS quality cuts)
ZERR_BEST	float64		Redshift error for Z_BEST
ZWARN_BEST	int32		Redshift warning bitmask for Z_BEST
SPECTYPE_BEST	char[6]		Spectral type for Z_BEST (e.g. GALAXY, QSO, STAR)
SUBTYPE_BEST	char[3]		Spectral subtype for Z_BEST
CHI2_BEST	float32		Best fit chi squared for Z_BEST
DELTACHI2_BEST	float32		chi2 difference between first- and second-best fits for Z_BEST
PETAL_LOC	int16		Petal location [0-9]
FIBER	int32		Fiber ID on the CCDs [0-4999]
COADD_FIBERSTATUS	int32		bitwise-AND of input FIBERSTATUS
TARGET_RA	float64	deg	Barycentric Right Ascension in ICRS
TARGET_DEC	float64	deg	Barycentric Declination in ICRS
DESINAME	char[22]		Human readable identifier of a sky location DESI JXXX.XXXX[+/-]YY.YYYY, where X,Y=truncated decimal TARGET_RA, TARGET_DEC, precise to 0.36 arcsec. Multiple objects can map to a single DESINAME if very close on the sky.
OBJTYPE	char[3]		Object type: TGT, SKY, NON, BAD
FIBERASSIGN_X	float32	mm	Fiberassign expected CS5 X location on focal plane
FIBERASSIGN_Y	float32	mm	Fiberassign expected CS5 Y location on focal plane
PRIORITY	int32		Target current priority
CMX_TARGET [1]	int64		Target selection bitmask for commissioning
SV1_DESI_TARGET [1]	int64		DESI (dark time program) target selection bitmask for SV1
SV1_BGS_TARGET [1]	int64		BGS (bright time program) target selection bitmask for SV1
SV1_MWS_TARGET [1]	int64		MWS (bright time program) target selection bitmask for SV1
SV1_SCND_TARGET [1]	int64		Secondary target selection bitmask for SV1
SV2_DESI_TARGET [1]	int64		DESI (dark time program) target selection bitmask for SV2
SV2_BGS_TARGET [1]	int64		BGS (bright time program) target selection bitmask for SV2
SV2_MWS_TARGET [1]	int64		MWS (bright time program) target selection bitmask for SV2
SV2_SCND_TARGET [1]	int64		Secondary target selection bitmask for SV2
SV3_DESI_TARGET [1]	int64		DESI (dark time program) target selection bitmask for SV3
SV3_BGS_TARGET [1]	int64		BGS (bright time program) target selection bitmask for SV3
SV3_MWS_TARGET [1]	int64		MWS (bright time program) target selection bitmask for SV3
SV3_SCND_TARGET [1]	int64		Secondary target selection bitmask for SV3
DESI_TARGET [1]	int64		DESI (dark time program) target selection bitmask
BGS_TARGET [1]	int64		BGS (bright time program) target selection bitmask
MWS_TARGET [1]	int64		MWS (bright time program) target selection bitmask
SCND_TARGET [1]	int64		Secondary target selection bitmask
COADD_NUMEXP	int16		Number of exposures in coadd
COADD_EXPTIME	float32	s	Summed exposure time for coadd
COADD_NUMNIGHT	int16		Number of nights in coadd
COADD_NUMTILE	int16		Number of tiles in coadd
MIN_MJD	float64	d	Minimum value of the Modified Julian Date (when the shutter was open for the first exposure used in the coadded spectrum)
MAX_MJD	float64	d	Maximum value of the Modified Julian Date (when the shutter was open for the last exposure used in the coadded spectrum)
MEAN_MJD	float64	d	Mean value of the Modified Julian Date (when the shutter was open for exposures used in the coadded spectrum)
GOOD_SPEC	logical		True if this is a science target with good hardware/fiber status
EFFTIME_SPEC	float32	s	Effective exposure time for spectroscopy (from TSNR2_LRG; see Notes)
ZCAT_NSPEC	int16		Number of times this TARGETID appears in this catalog
ZCAT_PRIMARY	logical		Boolean flag (True/False) for the primary coadded spectrum in this zcatalog
SV_NSPEC [1]	int16		Number of coadded spectra for this TARGETID in SV (SV1+2+3)
SV_PRIMARY [1]	logical		Boolean flag (True/False) for the primary coadded spectrum in SV (SV1+2+3)
MAIN_NSPEC [1]	int16		Number of coadded spectra for this TARGETID in Main survey
MAIN_PRIMARY [1]	logical		Boolean flag (True/False) for the primary coadded spectrum in Main survey

[1] (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23)

Optional

Notes

• SV_NSPEC and SV_PRIMARY are present when any SV (sv1/sv2/sv3) entries exist.

• MAIN_NSPEC and MAIN_PRIMARY are present when any SURVEY=main entries exist.

• The targeting bitmasks DESI_TARGET, BGS_TARGET, MWS_TARGET, and SCND_TARGET only apply to SURVEY="main" targets; they are not set for targets in other surveys.

• Similarly, the SV1_DESI_TARGET etc. target masks are only set for the corresponding survey; there is no propagation of targeting bits across surveys.

• EFFTIME_SPEC is the effective exposure time computed as SNR2TIME * TSNR2_X, where TSNR2_X is chosen by program: TSNR2_LRG for dark, TSNR2_BGS for bright, TSNR2_GPBBACKUP for backup. SNR2TIME is a per-tracer normalization factor from the TSNR ensemble template files in desimodel.