| Summary: | Redshifts and spectral classifications from Redrock. |
|---|---|
| Naming Convention: | redrock-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: | redrock-[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, 450 KB |
This file contains spectral classifications and redshifts for spectra coadded across exposures of an individual tile. For a similar file that also combined data across multiple tiles, see :doc:`healpix-based Redrock files </DESI_SPECTRO_REDUX/SPECPROD/healpix/SURVEY/PROGRAM/PIXGROUP/PIXNUM/redrock-SURVEY-PROGRAM-PIXNUM>`.
| Number | EXTNAME | Type | Contents |
|---|---|---|---|
| HDU0 | IMAGE | Keywords only | |
| HDU1 | REDSHIFTS | BINTABLE | Table with redshifts and spectral classifications |
| HDU2 | FIBERMAP | BINTABLE | Target photometry, metadata, and what fibers they are assigned to |
| HDU3 | EXP_FIBERMAP | BINTABLE | Per-exposure entries from input fibermaps |
| HDU4 | TSNR2 | BINTABLE | Template signal-to-noise values from input coadd SCORES table |
.. collapse:: Required Header Keywords Table
.. rst-class:: keywords
========== ============= ==== ===============
KEY Example Value Type Comment
========== ============= ==== ===============
LONGSTRN OGIP 1.0 str
RRVER 0.15.0 str Redrock version
TEMNAM00 GALAXY str Redrock template 00 name
TEMVER00 2.6 str Redrock template 00 version
TEMNAM01 QSO str
TEMVER01 0.1 str
TEMNAM02 STAR:::A str
TEMVER02 0.1 str
TEMNAM03 STAR:::B str
TEMVER03 0.1 str
TEMNAM04 STAR:::CV str
TEMVER04 0.1 str
TEMNAM05 STAR:::F str
TEMVER05 0.1 str
TEMNAM06 STAR:::G str
TEMVER06 0.1 str
TEMNAM07 STAR:::K str
TEMVER07 0.1 str
TEMNAM08 STAR:::M str
TEMVER08 0.1 str
TEMNAM09 STAR:::WD str
TEMVER09 0.1 str
SPGRP cumulative str Exposure grouping (pernight, cumulative, ...)
SPGRPVAL 20210205 int Value of grouping (night, expid, ...)
TILEID 80605 int DESI Tile ID
SPECTRO 6 int Spectrograph number
PETAL 6 int Focal plane petal number (same as SPECTRO)
NIGHT [1]_ 20210205 int (Last) night of data included, if applicable to grouping
========== ============= ==== ===============
Empty HDU.
EXTNAME = REDSHIFTS
Spectral classifications and redshifts from Redrock.
.. collapse:: Required Header Keywords Table
.. rst-class:: keywords
====== ============= ==== =====================
KEY Example Value Type Comment
====== ============= ==== =====================
NAXIS1 170 int Width of table in bytes
NAXIS2 500 int Number of targets in table
====== ============= ==== =====================
.. rst-class:: columns
| Name | Type | Units | Description |
|---|---|---|---|
| TARGETID | int64 | Unique DESI target ID | |
| CHI2 | float64 | Best fit chi squared | |
| COEFF | float64[10] | Redrock template coefficients | |
| Z | float64 | Redshift measured by Redrock | |
| ZERR | float64 | Redshift error from redrock | |
| ZWARN | int64 | Redshift warning bitmask from Redrock | |
| NPIXELS | int64 | Number of unmasked pixels contributing to the Redrock fit | |
| SPECTYPE | char[6] | Spectral type of Redrock best fit template (e.g. GALAXY, QSO, STAR) | |
| SUBTYPE | char[20] | Spectral subtype | |
| NCOEFF | int64 | Number of Redrock template coefficients | |
| DELTACHI2 | float64 | chi2 difference between first- and second-best redrock template fits |
EXTNAME = FIBERMAP
Fibermap with target metadata such as photometry, target selection bits, and what fibers each target was assigned to. This table is row-matched to the REDSHIFTS table.
.. collapse:: Required Header Keywords Table
.. rst-class:: keywords
====== ============= ==== =====================
KEY Example Value Type Comment
====== ============= ==== =====================
NAXIS1 371 int Width of table in bytes
NAXIS2 500 int Number of targets in table.
====== ============= ==== =====================
.. rst-class:: columns
| Name | Type | Units | Description |
|---|---|---|---|
| TARGETID | int64 | Unique DESI target ID | |
| PETAL_LOC | int16 | Petal location [0-9] | |
| DEVICE_LOC | int32 | Device location on focal plane [0-523] | |
| LOCATION | int64 | Location on the focal plane PETAL_LOC*1000 + DEVICE_LOC | |
| 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 |
| 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 |
| LAMBDA_REF | float32 | Angstrom | Requested wavelength at which targets should be centered on fibers |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| SCND_TARGET [1] | int64 | Target selection bitmask for secondary programs | |
| 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 |
| TILEID | int32 | Unique DESI tile ID | |
| 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 | |
| MEAN_FIBER_X | float32 | mm | Mean (over exposures) fiber CS5 X location on focal plane |
| MEAN_FIBER_Y | float32 | mm | Mean (over exposures) fiber CS5 Y location on focal plane |
| [1] | (1, 2, 3, 4, 5) Optional |
EXTNAME = EXP_FIBERMAP
Fibermap entries that vary from exposure to exposure, e.g. what exposures were include in the coadd and what focalplane (x,y) each target was located at for each exposure.
.. collapse:: Required Header Keywords Table
.. rst-class:: keywords
====== ============= ==== =====================
KEY Example Value Type Comment
====== ============= ==== =====================
NAXIS1 162 int Width of table in bytes
NAXIS2 500 int Number of input target-exposures = rows in table
====== ============= ==== =====================
.. rst-class:: columns
| Name | Type | Units | Description |
|---|---|---|---|
| TARGETID | int64 | Unique DESI target ID | |
| PRIORITY | int32 | Target current priority | |
| SUBPRIORITY | float64 | Random subpriority [0-1) to break assignment ties | |
| NIGHT | int32 | ||
| EXPID | int32 | DESI Exposure ID number | |
| MJD | float64 | Modified Julian Date when shutter was opened for this exposure | |
| TILEID | int32 | Unique DESI tile ID | |
| EXPTIME | float64 | s | Length of time shutter was open |
| PETAL_LOC | int16 | Petal location [0-9] | |
| DEVICE_LOC | int32 | Device location on focal plane [0-523] | |
| LOCATION | int64 | Location on the focal plane PETAL_LOC*1000 + DEVICE_LOC | |
| FIBER | int32 | Fiber ID on the CCDs [0-4999] | |
| FIBERSTATUS | int32 | Fiber status mask. 0=good | |
| FIBERASSIGN_X | float32 | mm | Fiberassign expected CS5 X location on focal plane |
| FIBERASSIGN_Y | float32 | mm | Fiberassign expected CS5 Y location on focal plane |
| LAMBDA_REF | float32 | Angstrom | Requested wavelength at which targets should be centered on fibers |
| 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 |
| NUM_ITER | int64 | Number of positioner iterations | |
| FIBER_X | float64 | mm | CS5 X location requested by PlateMaker |
| FIBER_Y | float64 | mm | CS5 Y location requested by PlateMaker |
| DELTA_X | float64 | mm | CS5 X requested minus actual position |
| DELTA_Y | float64 | mm | CS5 Y requested minus actual position |
| FIBER_RA | float64 | deg | RA of actual fiber position |
| FIBER_DEC | float64 | deg | DEC of actual fiber position |
| PSF_TO_FIBER_SPECFLUX | float64 | fraction of light from point-like source captured by 1.5 arcsec diameter fiber given atmospheric seeing |
EXTNAME = TSNR2
Template signal-to-noise squared. These quantities weight the observed (S/N)^2 by which wavelengths matter most for different target types, e.g. QSOs weight blue wavelengths more while ELGs weight redder wavelengths more due to the wavelengths of the observed emission lines. For more details, see section 4.14 of Guy et al 2023.
This table is row-matched to the REDSHIFTS table.
.. collapse:: Required Header Keywords Table
.. rst-class:: keywords
====== ============= ==== =====================
KEY Example Value Type Comment
====== ============= ==== =====================
NAXIS1 136 int Width of table in bytes.
NAXIS2 500 int Number of targets = number of table rows.
====== ============= ==== =====================
.. rst-class:: columns
| Name | Type | Units | Description |
|---|---|---|---|
| TARGETID | int64 | Unique DESI target ID | |
| 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 |
The REDSHIFTS, FIBERMAP, and TSNR2 tables are row-matched with one row per target. They also include a TARGETID column for confirmation and database-like joins with other tables. The EXP_FIBERMAP HDU has one row per target-exposure, and thus will have multiple entries per target when a target was observed on multiple input exposures.
This file is for redshifts from an individual spectrograph/petal of an individual tile. For a contatenation of all such files within a given survey and program, see the :doc:`ztile file </DESI_SPECTRO_REDUX/SPECPROD/zcatalog/ztile-SURVEY-PROGRAM-GROUPTYPE>`.
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, and PLATE_REF_EPOCH.
For targets with a non-zero proper motion, FIBER_RA and FIBER_DEC refer to the position at the reference epoch (but note that the proper-motion correction has been applied at the time of the observation, it is just not recorded in FIBER_RA and FIBER_DEC).