sptab_coadd

Summary:

FERRE results from coadded spectra for a given HEALPIX.

Naming Convention:

sptab_coadd-{SURVEY}-{PROGRAM}-{HEALPIX}.fits, where SURVEY is main, special, sv1, sv2, sv3, and PROGRAM is dark, bright, backup, other.

Regex:

sptab_coadd-.*-.*-.*.fits

File Type:

FITS, 135 KB

Contents

Number	EXTNAME	Type	Contents
HDU0		IMAGE	Empty HDU
HDU1	SPTAB	BINTABLE	FERRE results
HDU2	FIBERMAP	BINTABLE	Information about objects inherited from targeting
HDU3	SCORES	BINTABLE	Information about spectra quality
HDU4	AUX	BINTABLE	Auxiliary information: names of the parameters and chemical elements in the order used in building the PARAM and ELEM arrays in SPTAB

FITS Header Units

HDU0

Empty HDU.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
DATE	2023-04-09T03:26:22	str	Date of processing
FCONFIG	desi-sm.yaml	str	FERRE config information
HOST	login36	str	machine used
OS	posix	str	Operative system
PLATFORM	Linux 5.14.21-150400.24.46_12.0.63-cray_shasta_c	str	OS details
NSPEC	93	int	Number of spectra included
FTIME	5202.688	float	Compute time used by FERRE
STIME	2520.0	float	Compute time estimated for Slurm
NCORES	64	int	Number of cores in node
NTHREADS	12	int	Number of cores used by large FERRE instances
NUMPY	1.21.5	str	NumPy version
ASTROPY	5.1	str	AstroPy version
MATPLOTL	3.5.2	str	Matplotlib version
SCIPY	1.7.3	str	SciPy version
YAML	6.0	str	Yaml version
PYTHON	3.9.7	str	Python version
PIFERRE	0.4	str	Piferre version
FERRE	5.1.1	str	FERRE version

HDU1

EXTNAME = SPTAB

This is the table of measurements by FERRE of coadded DESI spectra for a given HEALPIX.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	545	int	length of dimension 1
NAXIS2	93	int	length of dimension 2

Required Data Table Columns

Name	Type	Units	Description
SUCCESS	int64		Bit indicating whether the code has likely produced useful results
TARGETID	int64		Unique DESI target ID
TARGET_RA	float64	deg	Barycentric right ascension in ICRS
TARGET_DEC	float64	deg	Barycentric declination in ICRS
REF_ID	int64		Tyc1*1,000,000+Tyc2*10+Tyc3 for Tycho-2; sourceid for Gaia DR2
REF_CAT	char[2]		Reference catalog source for star: ‘T2’ for Tycho-2, ‘G2’ for Gaia DR2, ‘L2’ for the SGA, empty otherwise
SRCFILE	char[23]		DESI data file
BESTGRID	char[8]		Model grid that produced the best fit
TEFF	float64	K	Effective temperature (K)
LOGG	float64		Surface gravity (g in cm/s**2)
FEH	float64		Metallicity [Fe/H] = log10(N(Fe)/N(H)) - log10(N(Fe)/N(H))sun
ALPHAFE	float64		Alpha-to-iron ratio [alpha/Fe]
LOG10MICRO	float64		Log10 of Microturbulence (km/s)
PARAM	float64[5]		Array of atmospheric parameters ([Fe/H], [a/Fe], log10micro, Teff,logg)
COVAR	float64[25]		Covariance matrix for ([Fe/H], [a/Fe], log10micro, Teff,logg)
ELEM	float64[10]		Elemental abundance ratios to hydrogen [elem/H]
ELEM_ERR	float64[10]		Uncertainties in the elemental abundance ratios
CHISQ_TOT	float64		Total chi**2
SNR_MED	float64		Median signal-to-ratio
RV_ADOP	float64	km s-1	Adopted Radial Velocity (km/s)
RV_ERR	float64	km s-1	Uncertainty in the adopted Radial Velocity (km/s)

HDU2

EXTNAME = FIBERMAP

FIBERMAP table with information on individual targets copied from original coadd file.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	317	int	length of dimension 1
NAXIS2	93	int	length of dimension 2

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique DESI target ID
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
PMRA	float32	mas yr^-1	proper motion in the +RA direction (already including cos(dec))
PMDEC	float32	mas yr^-1	Proper motion in the +Dec direction
REF_EPOCH	float32	yr	Reference epoch for Gaia/Tycho astrometry. Typically 2015.5 for Gaia
FA_TARGET	int64		Targeting bit internally used by fiberassign (linked with FA_TYPE)
FA_TYPE	binary		Fiberassign internal target type (science, standard, sky, safe, suppsky)
OBJTYPE	char[3]		Object type: TGT, SKY, NON, BAD
SUBPRIORITY	float64		Random subpriority [0-1) to break assignment ties
OBSCONDITIONS	int32		Bitmask of allowed observing conditions
RELEASE	int16		Imaging surveys release ID
BRICKNAME	char[8]		Brick name from tractor input
BRICKID	int32		Brick ID from tractor input
BRICK_OBJID	int32		Imaging Surveys OBJID on that brick
MORPHTYPE	char[4]		Imaging Surveys morphological type from Tractor
EBV	float32	mag	Galactic extinction E(B-V) reddening from SFD98
FLUX_G	float32	nanomaggy	Flux in the Legacy Survey g-band (AB)
FLUX_R	float32	nanomaggy	Flux in the Legacy Survey r-band (AB)
FLUX_Z	float32	nanomaggy	Flux in the Legacy Survey z-band (AB)
FLUX_W1	float32	nanomaggy	WISE flux in W1 (AB)
FLUX_W2	float32	nanomaggy	WISE flux in W2 (AB)
FLUX_IVAR_G	float32	nanomaggy^-2	Inverse variance of FLUX_G (AB)
FLUX_IVAR_R	float32	nanomaggy^-2	Inverse variance of FLUX_R (AB)
FLUX_IVAR_Z	float32	nanomaggy^-2	Inverse variance of FLUX_Z (AB)
FLUX_IVAR_W1	float32	nanomaggy^-2	Inverse variance of FLUX_W1 (AB)
FLUX_IVAR_W2	float32	nanomaggy^-2	Inverse variance of FLUX_W2 (AB)
FIBERFLUX_G	float32	nanomaggy	Predicted g-band flux within a fiber of diameter 1.5 arcsec from this object in 1 arcsec Gaussian seeing
FIBERFLUX_R	float32	nanomaggy	Predicted r-band flux within a fiber of diameter 1.5 arcsec from this object in 1 arcsec Gaussian seeing
FIBERFLUX_Z	float32	nanomaggy	Predicted z-band flux within a fiber of diameter 1.5 arcsec from this object in 1 arcsec Gaussian seeing
FIBERTOTFLUX_G	float32	nanomaggy	Predicted g-band flux within a fiber of diameter 1.5 arcsec from all sources at this location in 1 arcsec Gaussian seeing
FIBERTOTFLUX_R	float32	nanomaggy	Predicted r-band flux within a fiber of diameter 1.5 arcsec from all sources at this location in 1 arcsec Gaussian seeing
FIBERTOTFLUX_Z	float32	nanomaggy	Predicted z-band flux within a fiber of diameter 1.5 arcsec from all sources at this location in 1 arcsec Gaussian seeing
MASKBITS	int16		Bitwise mask from the imaging indicating potential issue or blending
SERSIC	float32		Power-law index for the Sersic profile model (MORPHTYPE=SER)
SHAPE_R	float32	arcsec	Half-light radius of galaxy model (>0)
SHAPE_E1	float32		Ellipticity component 1 of galaxy model for galaxy type MORPHTYPE
SHAPE_E2	float32		Ellipticity component 2 of galaxy model for galaxy type MORPHTYPE
REF_ID	int64		Tyc1*1,000,000+Tyc2*10+Tyc3 for Tycho-2; sourceid for Gaia DR2
REF_CAT	char[2]		Reference catalog source for star: T2 for Tycho-2, G2 for Gaia DR2, L2 for the SGA, empty otherwise
GAIA_PHOT_G_MEAN_MAG	float32	mag	Gaia G band magnitude
GAIA_PHOT_BP_MEAN_MAG	float32	mag	Gaia BP band magnitude
GAIA_PHOT_RP_MEAN_MAG	float32	mag	Gaia RP band magnitude
PARALLAX	float32	mas	Reference catalog parallax
PHOTSYS	char[1]		N for the MzLS/BASS photometric system, S for DECaLS
PRIORITY_INIT	int64		Target initial priority from target selection bitmasks and OBSCONDITIONS
NUMOBS_INIT	int64		Initial number of observations for target calculated across target selection bitmasks and OBSCONDITIONS
SCND_TARGET	int64		Target selection bitmask for secondary programs
DESI_TARGET	int64		DESI (dark time program) target selection bitmask
BGS_TARGET	int64		BGS (Bright Galaxy Survey) target selection bitmask
MWS_TARGET	int64		Milky Way Survey targeting bits
PLATE_RA	float64	deg	Barycentric Right Ascension in ICRS to be used by PlateMaker
PLATE_DEC	float64	deg	Barycentric Declination in ICRS to be used by PlateMaker
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
MEAN_DELTA_X	float32	mm	Mean (over exposures) fiber difference requested - actual CS5 X location on focal plane
RMS_DELTA_X	float32	mm	RMS (over exposures) of the fiber difference between measured and requested CS5 X location on focal plane
MEAN_DELTA_Y	float32	mm	Mean (over exposures) fiber difference requested - actual CS5 Y location on focal plane
RMS_DELTA_Y	float32	mm	RMS (over exposures) of the fiber difference between measured and requested CS5 Y location on focal plane
MEAN_FIBER_RA	float64	deg	Mean (over exposures) RA of actual fiber position
STD_FIBER_RA	float32	arcsec	Standard deviation (over exposures) of RA of actual fiber position
MEAN_FIBER_DEC	float64	deg	Mean (over exposures) DEC of actual fiber position
STD_FIBER_DEC	float32	arcsec	Standard deviation (over exposures) of DEC of actual fiber position
MEAN_PSF_TO_FIBER_SPECFLUX	float32		Mean of input exposures fraction of light from point-like source captured by 1.5 arcsec diameter fiber given atmospheric seeing

HDU3

EXTNAME = SCORES

The table with various quality information about spectra.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	172	int	length of dimension 1
NAXIS2	93	int	length of dimension 2

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique DESI target ID
INTEG_COADD_FLUX_B	float32
MEDIAN_COADD_FLUX_B	float32
MEDIAN_COADD_SNR_B	float32
INTEG_COADD_FLUX_R	float32
MEDIAN_COADD_FLUX_R	float32
MEDIAN_COADD_SNR_R	float32
INTEG_COADD_FLUX_Z	float32
MEDIAN_COADD_FLUX_Z	float32
MEDIAN_COADD_SNR_Z	float32
TSNR2_GPBDARK_B	float32
TSNR2_ELG_B	float32		ELG B template (S/N)^2
TSNR2_GPBBRIGHT_B	float32
TSNR2_LYA_B	float32		LYA B template (S/N)^2
TSNR2_BGS_B	float32		BGS B template (S/N)^2
TSNR2_GPBBACKUP_B	float32
TSNR2_QSO_B	float32		QSO B template (S/N)^2
TSNR2_LRG_B	float32		LRG B template (S/N)^2
TSNR2_GPBDARK_R	float32
TSNR2_ELG_R	float32		ELG R template (S/N)^2
TSNR2_GPBBRIGHT_R	float32
TSNR2_LYA_R	float32		LYA R template (S/N)^2
TSNR2_BGS_R	float32		BGS R template (S/N)^2
TSNR2_GPBBACKUP_R	float32
TSNR2_QSO_R	float32		QSO R template (S/N)^2
TSNR2_LRG_R	float32		LRG R template (S/N)^2
TSNR2_GPBDARK_Z	float32
TSNR2_ELG_Z	float32		ELG Z template (S/N)^2
TSNR2_GPBBRIGHT_Z	float32
TSNR2_LYA_Z	float32		LYA Z template (S/N)^2
TSNR2_BGS_Z	float32		BGS Z template (S/N)^2
TSNR2_GPBBACKUP_Z	float32
TSNR2_QSO_Z	float32		QSO Z template (S/N)^2
TSNR2_LRG_Z	float32		LRG Z template (S/N)^2
TSNR2_GPBDARK	float32
TSNR2_ELG	float32		ELG template (S/N)^2 summed over B,R,Z
TSNR2_GPBBRIGHT	float32
TSNR2_LYA	float32		LYA template (S/N)^2 summed over B,R,Z
TSNR2_BGS	float32		BGS template (S/N)^2 summed over B,R,Z
TSNR2_GPBBACKUP	float32
TSNR2_QSO	float32		QSO template (S/N)^2 summed over B,R,Z
TSNR2_LRG	float32		LRG template (S/N)^2 summed over B,R,Z

HDU4

EXTNAME = AUX

Additional information on the order of the parameters and elements in the arrays PARAM and ELEM, respectively.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	70	int	length of dimension 1
NAXIS2	1	int	length of dimension 2

Required Data Table Columns

Name	Type	Units	Description
p	char[50]		The names of atmospheric parameters in the FERRE fit
e	char[20]		The names of elements for which abundances were derived