| Summary: | This file records simple (Gaussian) emission line fits on the spectra for few major lines. |
|---|---|
| Naming Convention: | emline-SPECTROGRAPH-TILEID-GROUPID.fits, where
SPECTROGRAPH is the spectrograph ID, TILEID is the tile number and
GROUPID depends on the GROUPTYPE of the tile coadd. |
| Regex: | emline-[0-9]-[0-9]+-([14]xsubset[1-6]|lowspeedsubset[1-6]|exp[0-9]{8}|thru[0-9]{8}|[0-9]{8})\.fits |
| File Type: | FITS, 188 KB |
| Number | EXTNAME | Type | Contents |
|---|---|---|---|
| HDU0 | IMAGE | Empty | |
| HDU1 | EMLINEFIT | BINTABLE | Emission line fits table |
Empty HDU.
EXTNAME = EMLINEFIT
Table with the emission line fit results for few major lines.
.. collapse:: Required Header Keywords Table
.. rst-class:: keywords
======== =============================================================================================== ===== =======================
KEY Example Value Type Comment
======== =============================================================================================== ===== =======================
NAXIS1 345 int width of table in bytes
NAXIS2 500 int number of rows in table
RRFN /global/cfs/cdirs/desi/spectro/redux/fuji/tiles/1x_depth/80608/5/redrock-1-80608-1xsubset5.fits str full path to the redrock file which contains the redshifts
COADDFN /global/cfs/cdirs/desi/spectro/redux/fuji/tiles/1x_depth/80608/5/coadd-1-80608-1xsubset5.fits str full path to the coadd file which contains the spectra
RFHW 40 int [Angstrom] rest-frame wavelength width used for fitting on each side of the line
MINRFHW 20 int [Angstrom] minimum requested *rest-frame* width on each side of the line to consider the fitting
RFCONTW 200 int [Angstrom] rest-frame wavelength extent to fit the continuum
RV 3.1 float value of R_V to convert EBV to magnitudes
EMNAMES OII,HDELTA,HGAMMA,HBETA,OIII,HALPHA str comma-separated list of emission lines to fit
RFWAVE00 3727.092,3729.874 str [Angstrom] rest-frame, vacuum, wavelength for the first emission line to fit
RFWAVE01 4102.892 str [Angstrom] rest-frame, vacuum, wavelength for the second emission line to fit
RFWAVE02 4341.684 str [Angstrom] rest-frame, vacuum, wavelength for the third emission line to fit
RFWAVE03 4862.683 str [Angstrom] rest-frame, vacuum, wavelength for the forth emission line to fit
RFWAVE04 4960.295,5008.239 str [Angstrom] rest-frame, vacuum, wavelength for the fifth emission line to fit
RFWAVE05 6564.613 str [Angstrom] rest-frame, vacuum, wavelength for the sixth emission line to fit
======== =============================================================================================== ===== =======================
.. rst-class:: columns
| Name | Type | Units | Description |
|---|---|---|---|
| TARGETID | int64 | Unique DESI target ID | |
| Z | float64 | Redshift measured by Redrock | |
| ZWARN | int64 | Redshift warning bitmask from Redrock | |
| SPECTYPE | char[6] | Spectral type of Redrock best fit template (e.g. GALAXY, QSO, STAR) | |
| DELTACHI2 | float64 | chi2 difference between first- and second-best redrock template fits | |
| TARGET_RA | float64 | deg | Target right ascension |
| TARGET_DEC | float64 | deg | Target declination |
| OBJTYPE | char[3] | Object type: TGT, SKY, NON, BAD | |
| OII_FLUX | float32 | 10**-17 erg/(s cm2) | Fitted flux for the [OII] doublet |
| OII_FLUX_IVAR | float32 | 10**+34 (s2 cm4) / erg2 | Inverse variance of the fitted flux for the [OII] doublet |
| OII_SIGMA | float32 | Angstrom | Fitted line width (in the observed frame) for the [OII] doublet |
| OII_SIGMA_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted line width (in the observed frame) for the [OII] doublet |
| OII_CONT | float32 | 10**-17 erg/(s cm2 Angstrom) | Continuum used for the fitting (fixed value) for the [OII] doublet |
| OII_CONT_IVAR | float32 | 10**+34 (s2 cm4 Angstrom2) / erg2 | Inverse variance of the continuum for the [OII] doublet |
| OII_SHARE | float32 | Fitted F1/(F0+F1) for the [OII] doublet, where F0 and F1 are the individual line fluxes | |
| OII_SHARE_IVAR | float32 | Inverse variance of the fitted F1/(F0+F1) for the [OII] doublet | |
| OII_EW | float32 | Angstrom | Fitted rest-frame equivalent width for the [OII] doublet |
| OII_EW_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted rest-frame equivalent width for the [OII] doublet |
| OII_CHI2 | float32 | Reduced chi2 of the fit for the [OII] doublet | |
| OII_NDOF | int32 | Number of degrees of freedom of the fit for the [OII] doublet | |
| HDELTA_FLUX | float32 | 10**-17 erg/(s cm2) | Fitted flux for the HDELTA line |
| HDELTA_FLUX_IVAR | float32 | 10**+34 (s2 cm4) / erg2 | Inverse variance of the fitted flux for the HDELTA line |
| HDELTA_SIGMA | float32 | Angstrom | Fitted line width (in the observed frame) for the HDELTA line |
| HDELTA_SIGMA_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted line width (in the observed frame) for the HDELTA line |
| HDELTA_CONT | float32 | 10**-17 erg/(s cm2 Angstrom) | Continuum used for the fitting (fixed value) for the HDELTA line |
| HDELTA_CONT_IVAR | float32 | 10**+34 (s2 cm4 Angstrom2) / erg2 | Inverse variance of the continuum for the HDELTA line |
| HDELTA_SHARE | float32 | NaN (SHARE not relevant for HDELTA line) | |
| HDELTA_SHARE_IVAR | float32 | NaN (SHARE not relevant for HDELTA line) | |
| HDELTA_EW | float32 | Angstrom | Fitted rest-frame equivalent width for the HDELTA line |
| HDELTA_EW_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted rest-frame equivalent width for the HDELTA line |
| HDELTA_CHI2 | float32 | Reduced chi2 of the fit for the HDELTA line | |
| HDELTA_NDOF | int32 | Number of degrees of freedom of the fit for the HDELTA line | |
| HGAMMA_FLUX | float32 | 10**-17 erg/(s cm2) | Fitted flux for the HGAMMA line |
| HGAMMA_FLUX_IVAR | float32 | 10**+34 (s2 cm4) / erg2 | Inverse variance of the fitted flux for the HGAMMA line |
| HGAMMA_SIGMA | float32 | Angstrom | Fitted line width (in the observed frame) for the HGAMMA line |
| HGAMMA_SIGMA_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted line width (in the observed frame) for the HGAMMA line |
| HGAMMA_CONT | float32 | 10**-17 erg/(s cm2 Angstrom) | Continuum used for the fitting (fixed value) for the HGAMMA line |
| HGAMMA_CONT_IVAR | float32 | 10**+34 (s2 cm4 Angstrom2) / erg2 | Inverse variance of the continuum for the HGAMMA line |
| HGAMMA_SHARE | float32 | NaN (SHARE not relevant for HGAMMA line) | |
| HGAMMA_SHARE_IVAR | float32 | NaN (SHARE not relevant for HGAMMA line) | |
| HGAMMA_EW | float32 | Angstrom | Fitted rest-frame equivalent width for the HGAMMA line |
| HGAMMA_EW_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted rest-frame equivalent width for the HGAMMA line |
| HGAMMA_CHI2 | float32 | Reduced chi2 of the fit for the HGAMMA line | |
| HGAMMA_NDOF | int32 | Number of degrees of freedom of the fit for the HGAMMA line | |
| HBETA_FLUX | float32 | 10**-17 erg/(s cm2) | Fitted flux for the HBETA line |
| HBETA_FLUX_IVAR | float32 | 10**+34 (s2 cm4) / erg2 | Inverse variance of the fitted flux for the HBETA line |
| HBETA_SIGMA | float32 | Angstrom | Fitted line width (in the observed frame) for the HBETA line |
| HBETA_SIGMA_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted line width (in the observed frame) for the HBETA line |
| HBETA_CONT | float32 | 10**-17 erg/(s cm2 Angstrom) | Continuum used for the fitting (fixed value) for the HBETA line |
| HBETA_CONT_IVAR | float32 | 10**+34 (s2 cm4 Angstrom2) / erg2 | Inverse variance of the continuum for the HBETA line |
| HBETA_SHARE | float32 | NaN (SHARE not relevant for HBETA line) | |
| HBETA_SHARE_IVAR | float32 | NaN (SHARE not relevant for HBETA line) | |
| HBETA_EW | float32 | Angstrom | Fitted rest-frame equivalent width for the HBETA line |
| HBETA_EW_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted rest-frame equivalent width for the HBETA line |
| HBETA_CHI2 | float32 | Reduced chi2 of the fit for the HBETA line | |
| HBETA_NDOF | int32 | Number of degrees of freedom of the fit for the HBETA line | |
| OIII_FLUX | float32 | 10**-17 erg/(s cm2) | Fitted flux for the [OIII] doublet |
| OIII_FLUX_IVAR | float32 | 10**+34 (s2 cm4) / erg2 | Inverse variance of the fitted flux for the [OIII] doublet |
| OIII_SIGMA | float32 | Angstrom | Fitted line width (in the observed frame) for the [OIII] doublet |
| OIII_SIGMA_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted line width (in the observed frame) for the [OIII] doublet |
| OIII_CONT | float32 | 10**-17 erg/(s cm2 Angstrom) | Continuum used for the fitting (fixed value) for the [OIII] doublet |
| OIII_CONT_IVAR | float32 | 10**+34 (s2 cm4 Angstrom2) / erg2 | Inverse variance of the continuum for the [OIII] doublet |
| OIII_SHARE | float32 | F1/(F0+F1) for the [OIII] doublet, where F0 and F1 are the individual line fluxes (SHARE value fixed during the fit) | |
| OIII_SHARE_IVAR | float32 | Infinite value, as SHARE is fixed during the fit | |
| OIII_EW | float32 | Angstrom | Fitted rest-frame equivalent width for the [OIII] doublet |
| OIII_EW_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted rest-frame equivalent width for the [OIII] doublet |
| OIII_CHI2 | float32 | Reduced chi2 of the fit for the [OIII] doublet | |
| OIII_NDOF | int32 | Number of degrees of freedom of the fit for the [OIII] doublet | |
| HALPHA_FLUX | float32 | 10**-17 erg/(s cm2) | Fitted flux for the HALPHA line |
| HALPHA_FLUX_IVAR | float32 | 10**+34 (s2 cm4) / erg2 | Inverse variance of the fitted flux for the HALPHA line |
| HALPHA_SIGMA | float32 | Angstrom | Fitted line width (in the observed frame) for the HALPHA line |
| HALPHA_SIGMA_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted line width (in the observed frame) for the HALPHA line |
| HALPHA_CONT | float32 | 10**-17 erg/(s cm2 Angstrom) | Continuum used for the fitting (fixed value) for the HALPHA line |
| HALPHA_CONT_IVAR | float32 | 10**+34 (s2 cm4 Angstrom2) / erg2 | Inverse variance of the continuum for the HALPHA line |
| HALPHA_SHARE | float32 | NaN (SHARE not relevant for HALPHA line) | |
| HALPHA_SHARE_IVAR | float32 | NaN (SHARE not relevant for HALPHA line) | |
| HALPHA_EW | float32 | Angstrom | Fitted rest-frame equivalent width for the HALPHA line |
| HALPHA_EW_IVAR | float32 | Angstrom^-2 | Inverse variance of the fitted rest-frame equivalent width for the HALPHA line |
| HALPHA_CHI2 | float32 | Reduced chi2 of the fit for the HALPHA line | |
| HALPHA_NDOF | int32 | Number of degrees of freedom of the fit for the HALPHA line |
- The fit is done with the desispec.scripts.emline script.
- [OII] is fit as a doublet (3927 and 3929), with the line ratio left free during the fit.
- [OIII] is fit as a doublet (4960 and 5007), with the line ratio fixed during the fit.
- The SHARE is fitted only for the [OII] doublet; for the [OIII] doublet, its value is fixed (hence the infinite OIII_SHARE_IVAR); for the other lines, the SHARE is not used, and NaN are reported.
- If there are not enough pixels to fit or if the fit fails, NaN values are reported.
- The default settings are designed for the ELGs (e.g. max_sigma); values to be interpreted with caution for the other targets.
- The fitted flux is not forced to be positive, so negative values can happen.
- The Z,ZWARN,SPECTYPE,DELTACHI2 (TARGET_RA,TARGET_DEC,OBJTYPE, respectively) columns come from the REDSHIFTS (FIBERMAP, respectively) extension of the input redrock file (see :doc:`redrock-SPECTROGRAPH-TILEID-GROUPID <redrock-SPECTROGRAPH-TILEID-GROUPID>`).
- For the SURVEY=cmx m33 tile (TILEID=80615) tile and all the SURVEY=sv1 tiles (except TILEID=80971-80976, the dc3r2 ones), proper-motion correction was applied at the :doc:`fiberassign </DESI_TARGET/fiberassign/tiles/TILES_VERSION/TILEXX/fiberassign-TILEID>` design step; thus the following columns can have different values than in the :doc:`desitarget products </DESI_TARGET/TARG_DIR/DR/VERSION/targets/PHASE/RESOLVE/OBSCON/PHASEtargets-OBSCON-RESOLVE-hp-HP>`:
TARGET_RA,TARGET_DEC,REF_EPOCH,PLATE_RA,PLATE_DEC, andPLATE_REF_EPOCH.