DESI Strong Lensing Catalog¶
Overview¶
Strong Lensing Catalog provides a comprehensive catalog of spectroscopic observation of strong gravitational lenses observed by DESI. The observations are primarily obtained through a program that seeks to obtain spectroscopic redshifts for both the lensing galaxies and the lensed sources for \(\sim\)1800 new strong lensing candidate systems. Results from the observations are reported in Huang et al. (2025, in preparation) and Storfer et al. (2025, in preparation) for the EDR and DR2 samples, respectively. We note that only observations corresponding to DR1 data are included in the present catalog, which is a subset of the DR2 sample.
Data Access¶
Data URL: https://data.desi.lbl.gov/public/dr1/vac/dr1/strong-lensing
NERSC access:
/global/cfs/cdirs/desi/public/dr1/vac/dr1/strong-lensing
Documentation¶
Files¶
desi-sl-vac-v1.fits: Catalog of strong gravitational lenses in DESI DR1.
Data Model¶
EXTNAME = DESI_SL_CATALOG
| 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 |
| HEALPIX | INT32 | - | HEALPixel containing this location at NSIDE=64 in the NESTED scheme |
| SPGRPVAL | INT32 | - | Value by which spectra are grouped for a coadd (e.g. a YEARMMDD night) |
| Z | FLOAT64 | - | Redshift measured by Redrock |
| ZERR | FLOAT64 | - | Redshift error from redrock |
| ZWARN | INT64 | - | Redshift warning bitmask from Redrock |
| CHI2 | FLOAT64 | - | Best fit chi squared |
| COEFF | FLOAT64[10] | - | Redrock template coefficients |
| 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 |
| 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 | Reference catalog proper motion in the RA direction |
| PMDEC | FLOAT32 | mas yr^-1 | Reference catalog proper motion in the Dec direction |
| REF_EPOCH | FLOAT32 | yr | Reference catalog reference epoch (e.g., 2015.5 for Gaia DR2) |
| 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 | - | Flag the target to be observed in graytime. |
| RELEASE | INT16 | - | Legacy Surveys (LS) Release |
| BRICKNAME | CHAR[8] | - | Brick name from tractor input |
| BRICKID | INT32 | - | Brick ID from tractor input |
| BRICK_OBJID | INT32 | - | OBJID (unique to brick, but not to file) |
| MORPHTYPE | CHAR[4] | - | Morphological Model type |
| EBV | FLOAT32 | mag | Galactic extinction E(B-V) reddening from SFD98 |
| FLUX_G | FLOAT32 | nanomaggy | LS flux from tractor input (g) |
| FLUX_R | FLOAT32 | nanomaggy | LS flux from tractor input (r) |
| FLUX_Z | FLOAT32 | nanomaggy | LS flux from tractor input (z) |
| FLUX_W1 | FLOAT32 | nanomaggy | WISE flux in W1 |
| FLUX_W2 | FLOAT32 | nanomaggy | WISE flux in W2 |
| FLUX_IVAR_G | FLOAT32 | nanomaggy^-2 | Inverse Variance of FLUX_G |
| FLUX_IVAR_R | FLOAT32 | nanomaggy^-2 | Inverse Variance of FLUX_R |
| FLUX_IVAR_Z | FLOAT32 | nanomaggy^-2 | Inverse Variance of FLUX_Z |
| FLUX_IVAR_W1 | FLOAT32 | nanomaggy^-2 | Inverse Variance of FLUX_W1 |
| FLUX_IVAR_W2 | FLOAT32 | nanomaggy^-2 | Inverse Variance of FLUX_W2 |
| 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 indicating that an object touches a pixel in the coadd///maskbits maps, as cataloged on the DR9 bitmasks page |
| SERSIC | FLOAT32 | - | Power-law index for the Sersic profile model (type=”SER”) |
| SHAPE_R | FLOAT32 | arcsec | Half-light radius of galaxy model for galaxy type type (>0) |
| SHAPE_E1 | FLOAT32 | - | Ellipticity component 1 of galaxy model for galaxy type type |
| SHAPE_E2 | FLOAT32 | - | Ellipticity component 2 of galaxy model for galaxy type type |
| REF_ID | INT64 | - | Tyc11,000,000+Tyc210+Tyc3 for Tycho-2; “sourceid” for Gaia DR2 |
| REF_CAT | CHAR[2] | - | Reference catalog source for this star: “T2” for Tycho-2, “G2” for Gaia DR2, “L3” 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 |
| CMX_TARGET | INT64 | - | Target selection bitmask for commissioning |
| SV1_DESI_TARGET | INT64 | - | DESI (dark time program) target selection bitmask for SV1 |
| SV1_BGS_TARGET | INT64 | - | BGS (bright time program) target selection bitmask for SV1 |
| SV1_MWS_TARGET | INT64 | - | MWS (bright time program) target selection bitmask for SV1 |
| SV1_SCND_TARGET | INT64 | - | Secondary target selection bitmask for SV1 |
| SV2_DESI_TARGET | INT64 | - | DESI (dark time program) target selection bitmask for SV2 |
| SV2_BGS_TARGET | INT64 | - | BGS (bright time program) target selection bitmask for SV2 |
| SV2_MWS_TARGET | INT64 | - | MWS (bright time program) target selection bitmask for SV2 |
| SV2_SCND_TARGET | INT64 | - | Secondary target selection bitmask for SV2 |
| SV3_DESI_TARGET | INT64 | - | DESI (dark time program) target selection bitmask for SV3 |
| SV3_BGS_TARGET | INT64 | - | BGS (bright time program) target selection bitmask for SV3 |
| SV3_MWS_TARGET | INT64 | - | MWS (bright time program) target selection bitmask for SV3 |
| SV3_SCND_TARGET | INT64 | - | Secondary target selection bitmask for SV3 |
| DESI_TARGET | INT64 | - | DESI (dark time program) target selection bitmask |
| BGS_TARGET | INT64 | - | BGS (bright time program) target selection bitmask |
| MWS_TARGET | INT64 | - | MWS (bright time program) target selection bitmask |
| SCND_TARGET | INT64 | - | Secondary target selection bitmask |
| 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 |
| TSNR2_GPBDARK_B | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for dark targets in guider pass band on B |
| TSNR2_ELG_B | FLOAT32 | - | ELG B template \(\textrm{(S/N)}^2\) |
| TSNR2_GPBBRIGHT_B | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for bright targets in guider pass band on B |
| TSNR2_LYA_B | FLOAT32 | - | LYA B template \(\textrm{(S/N)}^2\) |
| TSNR2_BGS_B | FLOAT32 | - | BGS B template \(\textrm{(S/N)}^2\) |
| TSNR2_GPBBACKUP_B | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for backup targets in guider pass band on B |
| TSNR2_QSO_B | FLOAT32 | - | QSO B template \(\textrm{(S/N)}^2\) |
| TSNR2_LRG_B | FLOAT32 | - | LRG B template \(\textrm{(S/N)}^2\) |
| TSNR2_GPBDARK_R | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for dark targets in guider pass band on R |
| TSNR2_ELG_R | FLOAT32 | - | ELG R template \(\textrm{(S/N)}^2\) |
| TSNR2_GPBBRIGHT_R | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for bright targets in guider pass band on R |
| TSNR2_LYA_R | FLOAT32 | - | LYA R template \(\textrm{(S/N)}^2\) |
| TSNR2_BGS_R | FLOAT32 | - | BGS R template \(\textrm{(S/N)}^2\) |
| TSNR2_GPBBACKUP_R | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for backup targets in guider pass band on R |
| TSNR2_QSO_R | FLOAT32 | - | QSO R template \(\textrm{(S/N)}^2\) |
| TSNR2_LRG_R | FLOAT32 | - | LRG R template \(\textrm{(S/N)}^2\) |
| TSNR2_GPBDARK_Z | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for dark targets in guider pass band on Z |
| TSNR2_ELG_Z | FLOAT32 | - | ELG Z template \(\textrm{(S/N)}^2\) |
| TSNR2_GPBBRIGHT_Z | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for bright targets in guider pass band on Z |
| TSNR2_LYA_Z | FLOAT32 | - | LYA Z template \(\textrm{(S/N)}^2\) |
| TSNR2_BGS_Z | FLOAT32 | - | BGS Z template \(\textrm{(S/N)}^2\) |
| TSNR2_GPBBACKUP_Z | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for backup targets in guider pass band on Z |
| TSNR2_QSO_Z | FLOAT32 | - | QSO Z template \(\textrm{(S/N)}^2\) |
| TSNR2_LRG_Z | FLOAT32 | - | LRG Z template \(\textrm{(S/N)}^2\) |
| TSNR2_GPBDARK | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for dark targets in guider pass band |
| TSNR2_ELG | FLOAT32 | - | ELG template \(\textrm{(S/N)}^2\) summed over B,R,Z |
| TSNR2_GPBBRIGHT | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for bright targets in guider pass band |
| TSNR2_LYA | FLOAT32 | - | LYA template \(\textrm{(S/N)}^2\) summed over B,R,Z |
| TSNR2_BGS | FLOAT32 | - | BGS template \(\textrm{(S/N)}^2\) summed over B,R,Z |
| TSNR2_GPBBACKUP | FLOAT32 | - | template \(\textrm{(S/N)}^2\) for backup targets in guider pass band |
| TSNR2_QSO | FLOAT32 | - | QSO template \(\textrm{(S/N)}^2\) summed over B,R,Z |
| TSNR2_LRG | FLOAT32 | - | LRG template \(\textrm{(S/N)}^2\) summed over B,R,Z |
| SV_NSPEC 1 | INT32 | - | Number of coadded spectra for this TARGETID in SV (SV1+2+3) |
| SV_PRIMARY 1 | BOOLEAN | - | Boolean flag (True/False) for the primary coadded spectrum in SV (SV1+2+3) |
| MAIN_NSPEC 1 | INT32 | - | Number of coadded spectra for this TARGETID in Main survey |
| MAIN_PRIMARY 1 | BOOLEAN | - | Boolean flag (True/False) for the primary coadded spectrum in Main survey |
| ZCAT_NSPEC | INT16 | - | Number of times this TARGETID appears in this catalog |
| ZCAT_PRIMARY | BOOLEAN | - | Boolean flag (True/False) for the primary coadded spectrum in this zcatalog |
| SFR | FLOAT32 | Msun yr^-1 | Instantaneous star formation rate (h=1.0, Chabrier+2003 initial mass function) |
| VDISP | FLOAT32 | km s^-1 | Stellar velocity dispersion |
| VDISP_IVAR | FLOAT32 | s^2 km^-2 | Inverse variance of VDISP |
| LOGMSTAR | FLOAT32 | Msun | Logarithmic stellar mass (h=1.0, Chabrier+2003 initial mass function) |
Contact¶
Contact Christopher Storfer or Xiaosheng Huangwith any questions.