Fastspec Data Model

Summary:

Spectrophotometric fitting results.

Naming Convention:

fastspec-SURVEY-PROGRAM-HEALPIX.fits.gz, where SURVEY is the survey name (e.g., main or sv3), PROGRAM is the program name (e.g., bright or dark), and HEALPIX is the healpixel number.

Regex:

fastspec-(cmx|main|special|sv1|sv2|sv3)-(backup|bright|dark|other)-[0-9]+\.fits.gz

File Type:

FITS

Contents

Number	EXTNAME	Type	Contents
HDU00	PRIMARY	IMAGE	Keywords only.
HDU01	METADATA	BINTABLE	Table with sample metadata.
HDU02	SPECPHOT	BINTABLE	Table with spectrophotometric quantities.
HDU03	FASTSPEC	BINTABLE	Table with spectral fitting results.
HDU04	MODELS	IMAGE	Model continuum, smooth continuum, and emission-line spectra.

FITS Header Units

HDU00

EXTNAME = PRIMARY

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
SPECPROD	iron	str	Spectroscopic production name.
COADDTYP	healpix	str	Type of spectral coadd (healpix|cumulative|pernight|perexp).
INPUTZ	F	bool	Input redshifts provided.
INPUTS	F	bool	Input seeds provided.
CONSAGE	F	bool	Stellar population synthesis ages constrained by redshift.
USEQNET	T	bool	QuasarNet redshifts used where applicable.
NMONTE	50	int	Number of Monte Carlo realizations.
SEED	1	int	Random seed used for Monte Carlo realizations.
NOSCORR	F	bool	No smooth continuum correction derived.
NOPHOTO	F	bool	No fitting to photometry carried out.
BRDLFIT	T	bool	Broad Balmer emission-line modeling attempted.
UFLOOR	0.01	float	Spectroscopic fractional uncertainty floor.
SNRBBALM	2.5	float	Minimum broad Balmer signal-to-noise ratio.
CHECKSUM	ZHWHZHVFZHVFZHVF	str	HDU checksum updated 2022-08-02T19:06:22
DATASUM	0	str	data unit checksum updated 2022-08-02T19:06:22

Empty HDU.

HDU01

EXTNAME = METADATA

Metadata associated with each object fitted.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	339	int	length of dimension 1
NAXIS2	338	int	length of dimension 2
CHECKSUM	hFY6jCV3hCV3hCV3	str	HDU checksum updated 2022-08-03T14:25:08
DATASUM	1759692941	str	data unit checksum updated 2022-08-03T14:25:08

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique target ID.
SURVEY [1]	bytes3		Survey name.
PROGRAM [1]	bytes6		Program name.
HEALPIX [1]	int32		Healpixel number.
TILEID [2]	int32		Tile ID number.
FIBER [2]	int32		Fiber number.
NIGHT [2]	int32		Night of observation.
EXPID [3]	int32		Exposure ID number.
TILEID_LIST	str?		List of tile IDs that went into healpix coadd.
RA	float64	deg	Right ascension from target catalog.
DEC	float64	deg	Declination from target catalog.
COADD_FIBERSTATUS	int64		Fiber status bit.
CMX_TARGET [5]	int64		Commissioning (CMX) targeting bit.
DESI_TARGET	int64		DESI targeting bit.
BGS_TARGET	int64		BGS targeting bit.
MWS_TARGET	int64		MWS targeting bit.
SCND_TARGET	int64		Secondary target targeting bit.
SV1_DESI_TARGET [5]	int64		SV1 DESI targeting bit.
SV1_BGS_TARGET [5]	int64		SV1 BGS targeting bit.
SV1_MWS_TARGET [5]	int64		SV1 MWS targeting bit.
SV2_DESI_TARGET [5]	int64		SV2 DESI targeting bit.
SV2_BGS_TARGET [5]	int64		SV2 BGS targeting bit.
SV2_MWS_TARGET [5]	int64		SV2 MWS targeting bit.
SV3_DESI_TARGET [5]	int64		SV3 DESI targeting bit.
SV3_BGS_TARGET [5]	int64		SV3 BGS targeting bit.
SV3_MWS_TARGET [5]	int64		SV3 MWS targeting bit.
SV1_SCND_TARGET [5]	int64		SV1 secondary targeting bit.
SV2_SCND_TARGET [5]	int64		SV2 secondary targeting bit.
SV3_SCND_TARGET [5]	int64		SV3 secondary targeting bit.
Z	float64		Redshift based on Redrock or QuasarNet (for QSO targets only).
ZWARN	int8		Redrock zwarning bit.
DELTACHI2	float64		Redrock delta-chi-squared.
SPECTYPE	str6		Redrock spectral classification type.
SUBTYPE	str20		Redrock spectral subtype.
Z_RR	float64		Redrock redshift.
TSNR2_BGS	float32		Template signal-to-noise ratio squared for BGS targets.
TSNR2_LRG	float32		Like TSNR2_BGS but for LRG targets.
TSNR2_ELG	float32		Like TSNR2_BGS but for ELG targets.
TSNR2_QSO	float32		Like TSNR2_BGS but for QSO targets.
TSNR2_LYA	float32		Like TSNR2_BGS but for LYA targets.
PHOTSYS	str1		Photometric system (N or S).
LS_ID	int64		Unique Legacy Surveys identification number.
FIBERFLUX_G	float32	nmgy	Fiber g-band flux corrected for Galactic extinction.
FIBERFLUX_R	float32	nmgy	Like FIBERFLUX_G but for the r-band.
FIBERFLUX_Z	float32	nmgy	Like FIBERFLUX_G but for the z-band.
FIBERTOTFLUX_G	float32	nmgy	Fibertot g-band flux corrected for Galactic extinction.
FIBERTOTFLUX_R	float32	nmgy	Like FIBERTOTFLUX_G but for the r-band.
FIBERTOTFLUX_Z	float32	nmgy	Like FIBERTOTFLUX_G but for the z-band.
FLUX_G	float32	nmgy	Total g-band flux corrected for Galactic extinction.
FLUX_R	float32	nmgy	Like FLUX_G but for the r-band.
FLUX_Z	float32	nmgy	Like FLUX_G but for the z-band.
FLUX_W1	float32	nmgy	Like FLUX_G but for the W1-band.
FLUX_W2	float32	nmgy	Like FLUX_G but for the W2-band.
FLUX_W3	float32	nmgy	Like FLUX_G but for the W3-band.
FLUX_W4	float32	nmgy	Like FLUX_G but for the W4-band.
FLUX_IVAR_G	float32	1 / nmgy2	Inverse variance of FLUX_G corrected for Galactic extinction.
FLUX_IVAR_R	float32	1 / nmgy2	Like FLUX_IVAR_G but for the r-band.
FLUX_IVAR_Z	float32	1 / nmgy2	Like FLUX_IVAR_G but for the z-band.
FLUX_IVAR_W1	float32	1 / nmgy2	Like FLUX_IVAR_G but for the W1-band.
FLUX_IVAR_W2	float32	1 / nmgy2	Like FLUX_IVAR_G but for the W2-band.
FLUX_IVAR_W3	float32	1 / nmgy2	Like FLUX_IVAR_G but for the W3-band.
FLUX_IVAR_W4	float32	1 / nmgy2	Like FLUX_IVAR_G but for the W4-band.
EBV	float32	mag	Milky Way foreground color excess.
MW_TRANSMISSION_G	float32		Milky Way foreground dust transmission factor [0-1] in the g-band.
MW_TRANSMISSION_R	float32		Like MW_TRANSMISSION_G but for the r-band.
MW_TRANSMISSION_Z	float32		Like MW_TRANSMISSION_G but for the z-band.
MW_TRANSMISSION_W1	float32		Like MW_TRANSMISSION_G but for the W1-band.
MW_TRANSMISSION_W2	float32		Like MW_TRANSMISSION_G but for the W2-band.
MW_TRANSMISSION_W3	float32		Like MW_TRANSMISSION_G but for the W3-band.
MW_TRANSMISSION_W4	float32		Like MW_TRANSMISSION_G but for the W4-band.

HDU02

EXTNAME = SPECPHOT

Table with spectrophotometric quantities.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	3115	int	length of dimension 1
NAXIS2	338	int	length of dimension 2
CHECKSUM	WLDnaKDlWKDlaKDl	str	HDU checksum updated 2022-08-03T14:25:08
DATASUM	756558178	str	data unit checksum updated 2022-08-03T14:25:08

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique target ID.
SURVEY [1]	bytes3		Survey name.
PROGRAM [1]	bytes6		Program name.
HEALPIX [1]	int32		Healpixel number.
TILEID [2]	int32		Tile ID number.
NIGHT [2]	int32		Night of observation.
FIBER [2]	int32		Fiber number.
EXPID [3]	int32		Exposure ID number.
SEED	int64		Random seed used for Monte Carlo realizations.
COEFF	float32[5]	1e-17 erg / (Angstrom cm2 s)	Stellar continuum coefficients.
RCHI2	float32		Reduced chi-squared of the full-spectrophotometric fit.
RCHI2_LINE	float32		Reduced chi-squared of the emission-line model fit.
RCHI2_CONT	float32		Reduced chi-squared of the fit to the stellar continuum.
RCHI2_PHOT	float32		Reduced chi-squared of the fit to the broadband photometry.
VDISP	float32	km / s	Stellar velocity dispersion.
VDISP_IVAR	float32	s2 / km2	Inverse variance of VDISP.
TAUV	float32		V-band dust optical depth of the integrated stellar population.
TAUV_IVAR	float32		Inverse variance of TAUV.
AGE	float32	Gyr	Light-weighted age.
AGE_IVAR	float32	1 / Gyr2	Inverse variance of AGE.
ZZSUN	float32		Logarithmic stellar metallicity relative to solar.
ZZSUN_IVAR	float32		Inverse variance of ZZSUN.
LOGMSTAR	float32	Msun	Logarithmic stellar mass (h=1.0, Chabrier+2003 initial mass function).
LOGMSTAR_IVAR	float32	1 / Msun2	Inverse variance of LOGMSTAR.
SFR	float32	Msun / yr	Instantaneous star formation rate (h=1.0, Chabrier+2003 initial mass function).
SFR_IVAR	float32	yr2 / Msun2	Inverse variance of SFR.
DN4000	float32		Narrow 4000-A break index (from Balogh et al. 1999) measured from the emission-line subtracted spectrum.
DN4000_OBS	float32		Narrow 4000-A break index measured from the observed spectrum.
DN4000_IVAR	float32		Inverse variance of DN4000_OBS and of DN4000.
DN4000_MODEL	float32		Narrow 4000-A break index measured from the best-fitting continuum model.
DN4000_MODEL_IVAR	float32		Inverse variance of DN4000_MODEL.
FLUX_SYNTH_G	float32	nmgy	g-band flux (in the PHOTSYS photometric system) synthesized from the observed spectrum.
FLUX_SYNTH_R	float32	nmgy	Like FLUX_SYNTH_G but for the r-band.
FLUX_SYNTH_Z	float32	nmgy	Like FLUX_SYNTH_G but for the z-band.
FLUX_SYNTH_SPECMODEL_G	float32	nmgy	g-band flux (in the PHOTSYS photometric system) synthesized from the best-fitting spectroscopic model.
FLUX_SYNTH_SPECMODEL_R	float32	nmgy	Like FLUX_SYNTH_SPECMODEL_G but in the r-band.
FLUX_SYNTH_SPECMODEL_Z	float32	nmgy	Like FLUX_SYNTH_SPECMODEL_G but in the z-band.
FLUX_SYNTH_PHOTMODEL_G	float32	nmgy	g-band flux (in the PHOTSYS photometric system) synthesized from the best-fitting photometric continuum model.
FLUX_SYNTH_PHOTMODEL_R	float32	nmgy	Like FLUX_SYNTH_PHOTMODEL_G but in the r-band.
FLUX_SYNTH_PHOTMODEL_Z	float32	nmgy	Like FLUX_SYNTH_PHOTMODEL_G but in the z-band.
FLUX_SYNTH_PHOTMODEL_W1	float32	nmgy	Like FLUX_SYNTH_PHOTMODEL_G but in the W1-band.
FLUX_SYNTH_PHOTMODEL_W2	float32	nmgy	Like FLUX_SYNTH_PHOTMODEL_G but in the W2-band.
FLUX_SYNTH_PHOTMODEL_W3	float32	nmgy	Like FLUX_SYNTH_PHOTMODEL_G but in the W3-band.
FLUX_SYNTH_PHOTMODEL_W4	float32	nmgy	Like FLUX_SYNTH_PHOTMODEL_G but in the W4-band.
ABSMAG10_DECAM_G [4]	float32	mag	Absolute magnitude in DECam g-band band-shifted to z=1.0 assuming h=1.0.
ABSMAG10_IVAR_DECAM_G	float32	1 / mag2	Inverse variance corresponding to ABSMAG10_DECAM_G.
ABSMAG10_SYNTH_DECAM_G	float32	mag	Synthesized absolute magnitude in DECam g-band band-shifted to z=1.0 assuming h=1.0.
ABSMAG10_SYNTH_IVAR_DECAM_G	float32	1 / mag2	Inverse variance corresponding to ABSMAG10_SYNTH_DECAM_G.
ABSMAG10_DECAM_R [4]	float32	mag	Like ABSMAG10_DECAM_G but for DECam r-band.
ABSMAG10_IVAR_DECAM_R	float32	1 / mag2	Like ABSMAG10_IVAR_DECAM_G but for DECam r-band.
ABSMAG10_SYNTH_DECAM_R	float32	mag	Like ABSMAG10_SYNTH_DECAM_G but for DECam r-band.
ABSMAG10_SYNTH_IVAR_DECAM_R	float32	1 / mag2	Like ABSMAG10_SYNTH_IVAR_DECAM_G but for DECam r-band.
ABSMAG10_DECAM_Z [4]	float32	mag	Like ABSMAG10_DECAM_G but for DECam z-band.
ABSMAG10_IVAR_DECAM_Z	float32	1 / mag2	Like ABSMAG10_IVAR_DECAM_G but for DECam z-band.
ABSMAG10_SYNTH_DECAM_Z	float32	mag	Like ABSMAG10_SYNTH_DECAM_G but for DECam z-band.
ABSMAG10_SYNTH_IVAR_DECAM_Z	float32	1 / mag2	Like ABSMAG10_SYNTH_IVAR_DECAM_G but for DECam z-band.
ABSMAG00_U [4]	float32	mag	Absolute magnitude in Johnson/Cousins U-band band-shifted to z=0.0 assuming h=1.0.
ABSMAG00_IVAR_U	float32	1 / mag2	Inverse variance corresponding to ABSMAG00_U.
ABSMAG00_SYNTH_U	float32	mag	Synthesized absolute magnitude in Johnson/Cousins U-band band-shifted to z=0.0 assuming h=1.0.
ABSMAG00_SYNTH_IVAR_U	float32	1 / mag2	Inverse variance corresponding to ABSMAG00_SYNTH_U.
ABSMAG00_B [4]	float32	mag	Like ABSMAG00_U but for Johnson/Cousins B-band.
ABSMAG00_IVAR_B	float32	1 / mag2	Like ABSMAG00_IVAR_U but for Johnson/Cousins B-band.
ABSMAG00_SYNTH_B	float32	mag	Like ABSMAG00_SYNTH_U but for Johnson/Cousins B-band.
ABSMAG00_SYNTH_IVAR_B	float32	1 / mag2	Like ABSMAG00_SYNTH_IVAR_U but for Johnson/Cousins B-band.
ABSMAG00_V [4]	float32	mag	Like ABSMAG00_U but for Johnson/Cousins V-band.
ABSMAG00_IVAR_V	float32	1 / mag2	Like ABSMAG00_IVAR_U but for Johnson/Cousins V-band.
ABSMAG00_SYNTH_V	float32	mag	Like ABSMAG00_SYNTH_U but for Johnson/Cousins V-band.
ABSMAG00_SYNTH_IVAR_V	float32	1 / mag2	Like ABSMAG00_SYNTH_IVAR_U but for Johnson/Cousins V-band.
ABSMAG00_TWOMASS_J [4]	float32	mag	Absolute magnitude in 2MASS J-band band-shifted to z=0.0 assuming h=1.0.
ABSMAG00_IVAR_TWOMASS_J	float32	1 / mag2	Inverse variance corresponding to ABSMAG00_TWOMASS_J.
ABSMAG00_SYNTH_TWOMASS_J	float32	mag	Synthesized absolute magnitude in 2MASS J-band band-shifted to z=0.0 assuming h=1.0.
ABSMAG00_SYNTH_IVAR_TWOMASS_J	float32	1 / mag2	Inverse variance corresponding to ABSMAG01_SYNTH_TWOMASS_J.
ABSMAG01_SDSS_U [4]	float32	mag	Absolute magnitude in SDSS u-band band-shifted to z=0.1 assuming h=1.0.
ABSMAG01_IVAR_SDSS_U	float32	1 / mag2	Inverse variance corresponding to ABSMAG01_SDSS_U.
ABSMAG01_SYNTH_SDSS_U	float32	mag	Synthesized absolute magnitude in SDSS u-band band-shifted to z=0.1 assuming h=1.0.
ABSMAG01_SYNTH_IVAR_SDSS_U	float32	1 / mag2	Inverse variance corresponding to ABSMAG01_SYNTH_SDSS_U.
ABSMAG01_SDSS_G [4]	float32	mag	Like ABSMAG01_SDSS_U but for SDSS g-band.
ABSMAG01_IVAR_SDSS_G	float32	1 / mag2	Like ABSMAG01_IVAR_SDSS_U but for SDSS g-band.
ABSMAG01_SYNTH_SDSS_G	float32	mag	Like ABSMAG01_SYNTH_SDSS_U but for SDSS g-band.
ABSMAG01_SYNTH_IVAR_SDSS_G	float32	1 / mag2	Like ABSMAG01_SYNTH_IVAR_SDSS_U but for SDSS g-band.
ABSMAG01_SDSS_R [4]	float32	mag	Like ABSMAG01_SDSS_U but for SDSS r-band.
ABSMAG01_IVAR_SDSS_R	float32	1 / mag2	Like ABSMAG01_IVAR_SDSS_U but for SDSS r-band.
ABSMAG01_SYNTH_SDSS_R	float32	mag	Like ABSMAG01_SYNTH_SDSS_U but for SDSS r-band.
ABSMAG01_SYNTH_IVAR_SDSS_R	float32	1 / mag2	Like ABSMAG01_SYNTH_IVAR_SDSS_U but for SDSS r-band.
ABSMAG01_SDSS_I [4]	float32	mag	Like ABSMAG01_SDSS_U but for SDSS i-band.
ABSMAG01_IVAR_SDSS_I	float32	1 / mag2	Like ABSMAG01_IVAR_SDSS_U but for SDSS i-band.
ABSMAG01_SYNTH_SDSS_I	float32	mag	Like ABSMAG01_SYNTH_SDSS_U but for SDSS i-band.
ABSMAG01_SYNTH_IVAR_SDSS_I	float32	1 / mag2	Like ABSMAG01_SYNTH_IVAR_SDSS_U but for SDSS i-band.
ABSMAG01_SDSS_Z [4]	float32	mag	Like ABSMAG01_SDSS_U but for SDSS z-band.
ABSMAG01_IVAR_SDSS_Z	float32	1 / mag2	Like ABSMAG01_IVAR_SDSS_U but for SDSS z-band.
ABSMAG01_SYNTH_SDSS_Z	float32	mag	Like ABSMAG01_SYNTH_SDSS_U but for SDSS z-band.
ABSMAG01_SYNTH_IVAR_SDSS_Z	float32	1 / mag2	Like ABSMAG01_SYNTH_IVAR_SDSS_U but for SDSS z-band.
ABSMAG01_W1 [4]	float32	mag	Absolute magnitude in WISE W1-band band-shifted to z=0.1 assuming h=1.0.
ABSMAG01_IVAR_W1	float32	1 / mag2	Inverse variance corresponding to ABSMAG01_W1.
ABSMAG01_SYNTH_W1	float32	mag	Synthesized absolute magnitude in WISE W1-band band-shifted to z=0.1 assuming h=1.0.
ABSMAG01_SYNTH_IVAR_W1	float32	1 / mag2	Inverse variance corresponding to ABSMAG01_SYNTH_W1.
KCORR10_DECAM_G	float32	mag	K-correction used to derive ABSMAG10_DECAM_G band-shifted to z=1.0.
KCORR10_DECAM_R	float32	mag	Like KCORR10_DECAM_G but for DECam r-band.
KCORR10_DECAM_Z	float32	mag	Like KCORR10_DECAM_G but for DECam z-band.
KCORR00_U	float32	mag	K-correction used to derive ABSMAG00_U band-shifted to z=0.0.
KCORR00_B	float32	mag	Like KCORR00_U but for Johnson/Cousins B-band.
KCORR00_V	float32	mag	Like KCORR00_U but for Johnson/Cousins V-band.
KCORR01_SDSS_U	float32	mag	K-correction used to derive ABSMAG01_SDSS_U band-shifted to z=0.1.
KCORR01_SDSS_G	float32	mag	Like KCORR01_SDSS_U but for SDSS g-band.
KCORR01_SDSS_R	float32	mag	Like KCORR01_SDSS_U but for SDSS r-band.
KCORR01_SDSS_I	float32	mag	Like KCORR01_SDSS_U but for SDSS i-band.
KCORR01_SDSS_Z	float32	mag	Like KCORR01_SDSS_U but for SDSS z-band.
KCORR01_W1	float32	mag	K-correction used to derive ABSMAG01_W1 band-shifted to z=0.0.
LOGLNU_1500	float32	1e-28 erg / (Hz s)	Monochromatic luminosity at 1500 A in the rest-frame.
LOGLNU_1500_IVAR	float32	1e+56 Hz2 s2 / erg2	Inverse variance in LOGLNU_1500.
LOGLNU_2800	float32	1e-28 erg / (Hz s)	Monochromatic luminosity at 2800 A in the rest-frame.
LOGLNU_2800_IVAR	float32	1e+56 Hz2 s2 / erg2	Inverse variance in LOGLNU_2800.
LOGL_1450	float32	1e10 Lsun	Integrated luminosity at 1450 A in the rest-frame.
LOGL_1450_IVAR	float32	1e-20 / Lsun2	Inverse variance in LOGL_1450.
LOGL_1700	float32	1e10 Lsun	Integrated luminosity at 1700 A in the rest-frame.
LOGL_1700_IVAR	float32	1e-20 / Lsun2	Inverse variance in LOGL_1700.
LOGL_3000	float32	1e10 Lsun	Integrated luminosity at 3000 A in the rest-frame.
LOGL_3000_IVAR	float32	1e-20 / Lsun2	Inverse variance in LOGL_3000.
LOGL_5100	float32	1e10 Lsun	Integrated luminosity at 5100 A in the rest-frame.
LOGL_5100_IVAR	float32	1e-20 / Lsun2	Inverse variance in LOGL_5100.
FLYA_1215_CONT	float32	1e-17 erg / (Angstrom cm2 s)	Continuum flux at 1215.67 A in the rest-frame.
FLYA_1215_CONT_IVAR	float32	1e+34 cm4 Angstrom2 s2 / erg2	Inverse variance in FLYA_1215_CONT.
FOII_3727_CONT	float32	1e-17 erg / (Angstrom cm2 s)	Continuum flux at 3728.483 A in the rest-frame.
FOII_3727_CONT_IVAR	float32	1e+34 cm4 Angstrom2 s2 / erg2	Inverse variance in FOII_3727_CONT.
FHBETA_CONT	float32	1e-17 erg / (Angstrom cm2 s)	Continuum flux at 4862.683 A in the rest-frame.
FHBETA_CONT_IVAR	float32	1e+34 cm4 Angstrom2 s2 / erg2	Inverse variance in FHBETA_CONT.
FOIII_5007_CONT	float32	1e-17 erg / (Angstrom cm2 s)	Continuum flux at 5008.239 A in the rest-frame.
FOIII_5007_CONT_IVAR	float32	1e+34 cm4 Angstrom2 s2 / erg2	Inverse variance in FOIII_5007_CONT.
FHALPHA_CONT	float32	1e-17 erg / (Angstrom cm2 s)	Continuum flux at 6564.613 A in the rest-frame.
FHALPHA_CONT_IVAR	float32	1e+34 cm4 Angstrom2 s2 / erg2	Inverse variance in FHALPHA_CONT.

HDU03

EXTNAME = FASTSPEC

Table with spectral fitting results.

Required Header Keywords

Required Header Keywords Table

KEY	Example Value	Type	Comment
NAXIS1	3115	int	length of dimension 1
NAXIS2	338	int	length of dimension 2
CHECKSUM	WLDnaKDlWKDlaKDl	str	HDU checksum updated 2022-08-03T14:25:08
DATASUM	756558178	str	data unit checksum updated 2022-08-03T14:25:08

Required Data Table Columns

Name	Type	Units	Description
TARGETID	int64		Unique target ID.
SURVEY [1]	bytes3		Survey name.
PROGRAM [1]	bytes6		Program name.
HEALPIX [1]	int32		Healpixel number.
TILEID [2]	int32		Tile ID number.
NIGHT [2]	int32		Night of observation.
FIBER [2]	int32		Fiber number.
EXPID [3]	int32		Exposure ID number.
SNR_B	float32		Median signal-to-noise ratio per pixel in the b camera.
SNR_R	float32		Like SNR_B but in the r camera.
SNR_Z	float32		Like SNR_B but in z camera.
SMOOTHCORR_B	float32	percent	Median value of the smooth continuum correction relative to the data in the b camera.
SMOOTHCORR_R	float32	percent	Like SMOOTHCORR_B but in the r camera.
SMOOTHCORR_Z	float32	percent	Like SMOOTHCORR_B but in the z camera.
APERCORR	float32		Median aperture correction factor.
APERCORR_G	float32		Aperture correction factor measured in the g-band.
APERCORR_R	float32		Like APERCORR_G but measured in the r-band.
APERCORR_Z	float32		Like APERCORR_G but measured in the z-band.
INIT_SIGMA_UV	float32	km / s	Initial line width for the rest-frame UV emission lines.
INIT_SIGMA_NARROW	float32	km / s	Like INIT_SIGMA_UV but for the forbidden plus narrow Balmer emission lines.
INIT_SIGMA_BALMER	float32	km / s	Like INIT_SIGMA_UV but for broad Balmer emission lines.
INIT_VSHIFT_UV	float32	km / s	Initial velocity shift for the UV emission lines.
INIT_VSHIFT_NARROW	float32	km / s	Like INIT_VSHIFT_UV but for narrow (forbidden and narrow Balmer) emission lines.
INIT_VSHIFT_BALMER	float32	km / s	Like INIT_VSHIFT_UV but for broad Balmer emission lines.
INIT_BALMER_BROAD	bool		Boolean flag indicating whether a broad Balmer emission line was initially identified in the spectral range.
DELTA_LINECHI2	float32		Chi-squared difference between an emission-line model without and with broad lines.
DELTA_LINENDOF	int32		Difference in the degrees of freedom between an emission-line model without and with broad lines.
DELTA_KINECHI2	float32		Chi-squared difference between the constrained and relaxed emission-line model.
DELTA_KINENDOF	int32		Difference in the degrees of freedom between the constrained and relaxed emission-line model.
MGII_DOUBLET_RATIO	float32		MgII 2796 / 2803 doublet line-ratio.
MGII_DOUBLET_RATIO_IVAR	float32		Inverse variance in MGII_DOUBLET_RATIO.
OII_DOUBLET_RATIO	float32		[OII] 3726 / 3729 doublet line-ratio.
OII_DOUBLET_RATIO_IVAR	float32		Inverse variance in OII_DOUBLET_RATIO.
OIII_DOUBLET_RATIO	float32		[OIII] 5007 / 4959 doublet line-ratio.
OIII_DOUBLET_RATIO_IVAR	float32		Inverse variance in OIII_DOUBLET_RATIO.
SII_DOUBLET_RATIO	float32		[SII] 6731 / 6716 doublet line-ratio.
SII_DOUBLET_RATIO_IVAR	float32		Inverse variance in SII_DOUBLET_RATIO.
NII_DOUBLET_RATIO	float32		[NII] 6584 / 6548 doublet line-ratio.
NII_DOUBLET_RATIO_IVAR	float32		Inverse variance in NII_DOUBLET_RATIO.
OIIRED_DOUBLET_RATIO	float32		[OII] 7320 / 7330 doublet (actually a quadruplet) line-ratio.
OIIRED_DOUBLET_RATIO_IVAR	float32		Inverse variance in OIIRED_DOUBLET_RATIO.
LINENAME_MODELAMP [6]	float32	1e-17 erg / (Angstrom cm2 s)	Model emission-line amplitude (before convolution with the resolution matrix).
LINENAME_AMP [6]	float32	1e-17 erg / (Angstrom cm2 s)	Emission line amplitude.
LINENAME_AMP_IVAR [6]	float32	1e+34 Angstrom2 cm4 s2 / erg2	Inverse variance in LINENAME_AMP.
LINENAME_FLUX [6]	float32	1e-17 erg / (cm2 s)	Gaussian-integrated emission-line flux.
LINENAME_FLUX_IVAR [6]	float32	1e+34 cm4 s2 / erg2	Inverse variance in LINENAME_FLUX.
LINENAME_BOXFLUX [6]	float32	1e-17 erg / (cm2 s)	Boxcar-integrated emission-line flux.
LINENAME_BOXFLUX_IVAR [6]	float32	1e+34 cm4 s2 / erg2	Inverse variance in LINENAME_BOXFLUX.
LINENAME_VSHIFT [6]	float32	km / s	Velocity shift relative to Z.
LINENAME_VSHIFT_IVAR [6]	float32	s2 / km2	Inverse variance in LINENAME_VSHIFT.
LINENAME_SIGMA [6]	float32	km / s	Gaussian emission-line width (before convolution with the resolution matrix).
LINENAME_SIGMA_IVAR [6]	float32	s2 / km2	Inverse variance in LINENAME_SIGMA.
LINENAME_CONT [6]	float32	1e-17 erg / (Angstrom cm2 s)	Continuum flux at line center.
LINENAME_CONT_IVAR [6]	float32	1e+34 Angstrom2 cm4 s2 / erg2	Inverse variance in LINENAME_CONT.
LINENAME_EW [6]	float32	Angstrom	Rest-frame emission-line equivalent width.
LINENAME_EW_IVAR [6]	float32	1 / Angstrom2	Inverse variance in LINENAME_EW.
LINENAME_FLUX_LIMIT [6]	float32	erg / (cm2 s)	One-sigma upper-limit on the emission line flux.
LINENAME_CHI2 [6]	float32		Chi-squared of the line-fit.
LINENAME_NPIX [6]	int32		Number of pixels attributed to the emission line.
LINENAME2_MOMENT1 [7]	float32	Angstrom	First moment of the continuum-subtracted pixel values within +/- 5-sigma of the Gaussian line-center.
LINENAME2_MOMENT1_IVAR [7]	float32	1 / Angstrom2	Inverse variance in LINENAME2_MOMENT1.
LINENAME2_MOMENT2 [7]	float32	Angstrom2	Second moment of the flux relative to LINENAME2_MOMENT1.
LINENAME2_MOMENT2_IVAR [7]	float32	1 / Angstrom4	Inverse variance in LINENAME2_MOMENT2.
LINENAME2_MOMENT3 [7]	float32	Angstrom3	Third moment of the flux relative to LINENAME2_MOMENT1.
LINENAME2_MOMENT3_IVAR [7]	float32	1 / Angstrom6	Inverse variance in LINENAME2_MOMENT3.

HDU04

EXTNAME = MODELS

Best-fitting model spectra (corrected for Galactic extinction).

Required Header Keywords

Required Header Keywords Table

KEY	Example Value Type Comment
NAXIS1	7781	int	number of pixels
NAXIS2	3	int	number of models
NAXIS3	338	int	number of objects
BUNIT	10**-17 erg/(s cm2 Angstrom)	str	flux unit
CUNIT1	Angstrom	str	wavelength unit
CTYPE1	WAVE	str	type of axis
CRVAL1	3600.0	float	wavelength of pixel CRPIX1 (Angstrom)
CRPIX1	0	int	0-indexed pixel number corresponding to CRVAL1
CDELT1	0.8	float	pixel size (Angstrom)
DC-FLAG	0	int	0 = linear wavelength vector
AIRORVAC	vac	str	wavelengths in vacuum (vac)
CHECKSUM	Q9eTT8bTQ8bTQ8bT	str	HDU checksum updated 2022-08-03T14:25:08
DATASUM	3074907107	str	data unit checksum updated 2022-08-03T14:25:08

Data: FITS image [int32, 7781x3,338]

[1] (1,2,3,4,5,6,7,8,9)

Column only present when fitting healpix coadds.

[2] (1,2,3,4,5,6,7,8,9)

Column only present when fitting cumulative, per-night, or per-expopsure tile-based coadds.

[3] (1,2,3)

Column only present when fitting per-exposure tile-based coadds.

[4] (1,2,3,4,5,6,7,8,9,10,11,12,13)

Only observed photometry with a minimum signal-to-noise ratio of two is used to compute K-corrections. Absolute magnitudes are estimated using from the (S/N>2) observed-frame bandpass nearest in wavelength to the desired band-shifted rest-frame bandpass. If no observed-frame photometry is available, then the absolute magnitude is synthesized from the best-fitting model and the corresponding inverse variance is set to zero.

[5] (1,2,3,4,5,6,7,8,9,10,11,12,13)

Column only present in Commissioning and Survey Validation spectroscopic observations.

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

LINENAME represents the following modeled emission lines: NV_1240, OI_1304, SILIV_1396, CIV_1549, HEII_1640, ALIII_1857, SILIII_1892, CIII_1908, MGII_2796, MGII_2803, NEV_3346, NEV_3426, OII_3726, OII_3729, NEIII_3869, H6, H6_BROAD, HEPSILON, HEPSILON_BROAD, HDELTA, HDELTA_BROAD, HGAMMA, HGAMMA_BROAD, OIII_4363, HEI_4471, HEII_4686, HBETA, HBETA_BROAD, OIII_4959, OIII_5007, NII_5755, HEI_5876, OI_6300, SIII_6312, NII_6548, HALPHA, HALPHA_BROAD, NII_6584, SII_6716, SII_6731, ARIII_7135, OII_7320, OII_7330, SIII_9069, and SIII_9532.

[7] (1,2,3,4,5,6)

LINENAME2 represents the following emission lines: CIV_1549, MGII_2800 (using the mean wavelength of the doublet), HBETA, and OIII_5007.