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Table: ls_dr8.tractor
(The bold columns are indexed columns)
| Column Name | Description | Datatype |
|---|---|---|
| allmask_g | Bitwise mask set if the central pixel from all images satisfy each condition in g as cataloged on the DR8 bitmasks page | SMALLINT |
| allmask_r | Bitwise mask set if the central pixel from all images satisfy each condition in r as cataloged on the DR8 bitmasks page | SMALLINT |
| allmask_z | Bitwise mask set if the central pixel from all images satisfy each condition in z as cataloged on the DR8 bitmasks page | SMALLINT |
| anymask_g | Bitwise mask set if the central pixel from any image satisfies each condition in g as cataloged on the DR8 bitmasks page | SMALLINT |
| anymask_r | Bitwise mask set if the central pixel from any image satisfies each condition in r as cataloged on the DR8 bitmasks page | SMALLINT |
| anymask_z | Bitwise mask set if the central pixel from any image satisfies each condition in z as cataloged on the DR8 bitmasks page | SMALLINT |
| brick_primary | True if the object is within the brick boundary | SMALLINT |
| brickid | Brick ID [1,662174] | INTEGER |
| brickname | Name of brick, encoding the brick sky position, eg 1126p222 near RA=112.6, Dec=+22.2 | VARCHAR |
| brightblob | bitwise mask indicating that an object is near a bright foreground source, as cataloged on the DR8 bitmasks page (http://legacysurvey.org/dr8/bitmasksDR8 bitmasks) | SMALLINT |
| bx | X position (0-indexed) of coordinates in brick image stack | REAL |
| by | Y position (0-indexed) of coordinates in brick image stack | REAL |
| dchisq_1 | Difference in X^2 between successfully more-complex model fits | REAL |
| dchisq_2 | Difference in X^2 between successfully more-complex model fits | REAL |
| dchisq_3 | Difference in X^2 between successfully more-complex model fits | REAL |
| dchisq_4 | Difference in X^2 between successfully more-complex model fits | REAL |
| dchisq_5 | Difference in X^2 between successfully more-complex model fits | REAL |
| dec | Declination at equinox J2000 | DOUBLE |
| dec_ivar | Inverse variance of DEC, excluding astrometric calibration errors | REAL |
| dered_flux_g | Dereddened G-band flux | REAL |
| dered_flux_r | Dereddened R-band flux | REAL |
| dered_flux_w1 | Dereddened W1 flux | REAL |
| dered_flux_w2 | Dereddened W1 flux | REAL |
| dered_flux_w3 | Dereddened W1 flux | REAL |
| dered_flux_w4 | Dereddened W1 flux | REAL |
| dered_flux_z | Dereddened Z-band flux | REAL |
| dered_mag_g | Dereddened G-band magnitude | REAL |
| dered_mag_r | Dereddened R-band magnitude | REAL |
| dered_mag_w1 | Dereddened W1 magnitude | REAL |
| dered_mag_w2 | Dereddened W2 magnitude | REAL |
| dered_mag_w3 | Dereddened W3 magnitude | REAL |
| dered_mag_w4 | Dereddened W4 magnitude | REAL |
| dered_mag_z | Dereddened Z-band magnitude | REAL |
| ebv | Galactic extinction E(B-V) reddening from SFD98, used to compute the mw_transmission_ columns | REAL |
| elat | Ecliptic Latitude | DOUBLE |
| elon | Ecliptic Longitude | DOUBLE |
| fiberflux_g | Predicted g-band flux within a fiber from this object in 1 arcsec Gaussian seeing | REAL |
| fiberflux_r | Predicted r-band flux within a fiber from this object in 1 arcsec Gaussian seeing | REAL |
| fiberflux_z | Predicted z-band flux within a fiber from this object in 1 arcsec Gaussian seeing | REAL |
| fibertotflux_g | Predicted g-band flux within a fiber from all sources at this location in 1 arcsec Gaussian seeing | REAL |
| fibertotflux_r | Predicted r-band flux within a fiber from all sources at this location in 1 arcsec Gaussian seeing | REAL |
| fibertotflux_z | Predicted z-band flux within a fiber from all sources at this location in 1 arcsec Gaussian seeing | REAL |
| flux_g | model flux in g | REAL |
| flux_ivar_g | Inverse variance of flux_g | REAL |
| flux_ivar_r | Inverse variance of flux_r | REAL |
| flux_ivar_w1 | Inverse variance of flux_w1 (AB system) | REAL |
| flux_ivar_w2 | Inverse variance of flux_w2 (AB) | REAL |
| flux_ivar_w3 | Inverse variance of flux_w3 (AB) | REAL |
| flux_ivar_w4 | Inverse variance of flux_w4 (AB) | REAL |
| flux_ivar_z | Inverse variance of flux_z | REAL |
| flux_r | model flux in r | REAL |
| flux_w1 | WISE model flux in W1 (AB system) | REAL |
| flux_w2 | WISE model flux in W2 (AB) | REAL |
| flux_w3 | WISE model flux in W3 (AB) | REAL |
| flux_w4 | WISE model flux in W4 (AB) | REAL |
| flux_z | model flux in z | REAL |
| fracdev | Fraction of model in deVauc [0,1] | REAL |
| fracdev_ivar | Inverse variance of fracdev | REAL |
| fracflux_g | Profile-weighted fraction of the flux from other sources divided by the total flux in g (typically [0,1]) | REAL |
| fracflux_r | Profile-weighted fraction of the flux from other sources divided by the total flux in r (typically [0,1]) | REAL |
| fracflux_w1 | Profile-weighted fraction of the flux from other sources divided by the total flux in W1 (typically [0,1]) | REAL |
| fracflux_w2 | Profile-weighted fraction of the flux from other sources divided by the total flux in W2 (typically [0,1]) | REAL |
| fracflux_w3 | Profile-weighted fraction of the flux from other sources divided by the total flux in W3 (typically [0,1]) | REAL |
| fracflux_w4 | Profile-weighted fraction of the flux from other sources divided by the total flux in W4 (typically [0,1]) | REAL |
| fracflux_z | Profile-weighted fraction of the flux from other sources divided by the total flux in z (typically [0,1]) | REAL |
| fracin_g | Fraction of a source flux within the blob in g, near unity for real sources | REAL |
| fracin_r | Fraction of a source flux within the blob in r, near unity for real sources | REAL |
| fracin_z | Fraction of a source flux within the blob in z, near unity for real sources | REAL |
| fracmasked_g | Profile-weighted fraction of pixels masked from all observations of this object in g, strictly between [0,1] | REAL |
| fracmasked_r | Profile-weighted fraction of pixels masked from all observations of this object in r, strictly between [0,1] | REAL |
| fracmasked_z | Profile-weighted fraction of pixels masked from all observations of this object in z, strictly between [0,1] | REAL |
| g_r | Computed (g-r) color | REAL |
| gaia_astrometric_excess_noise | Gaia astrometric excess noise | REAL |
| gaia_astrometric_excess_noise_sig | Gaia astrometric excess noise uncertainty | REAL |
| gaia_astrometric_n_good_obs_al | Gaia number of good astrometric observations along scan direction | SMALLINT |
| gaia_astrometric_n_obs_al | Gaia number of astrometric observations along scan direction | SMALLINT |
| gaia_astrometric_weight_al | Gaia astrometric weight along scan direction | REAL |
| gaia_duplicated_source | Gaia duplicated source flag | SMALLINT |
| gaia_phot_bp_mean_flux_over_error | Gaia BP signal-to-noise | REAL |
| gaia_phot_bp_mean_mag | Gaia BP mag | REAL |
| gaia_phot_bp_n_obs | Gaia BP number of observations | SMALLINT |
| gaia_phot_g_mean_flux_over_error | Gaia G band signal-to-noise | REAL |
| gaia_phot_g_mean_mag | Gaia G band mag | REAL |
| gaia_phot_g_n_obs | Gaia G band number of observations | SMALLINT |
| gaia_phot_rp_mean_flux_over_error | Gaia RP signal-to-noise | REAL |
| gaia_phot_rp_mean_mag | Gaia RP mag | REAL |
| gaia_phot_rp_n_obs | Gaia RP number of observations | SMALLINT |
| gaia_phot_variable_flag | Gaia photometric variable flag | SMALLINT |
| gaia_pointsource | This Gaia DR2 source is believed to be a star, not a galaxy | SMALLINT |
| galdepth_g | As for PSFDEPTH_G but for a galaxy (0.45 arcsec exp, round) detection sensitivity | REAL |
| galdepth_r | As for PSFDEPTH_R but for a galaxy (0.45 arcsec exp, round) detection sensitivity | REAL |
| galdepth_z | As for PSFDEPTH_Z but for a galaxy (0.45 arcsec exp, round) detection sensitivity | REAL |
| glat | Galactic Latitude | DOUBLE |
| glon | Galactic Longitude | DOUBLE |
| htm9 | HTM index (order 9 => ~10 arcmin size) | INTEGER |
| ls_id | Unique LS object ID | BIGINT |
| mag_g | Converted G magnitude | REAL |
| mag_r | Converted R magnitude | REAL |
| mag_w1 | W1 magnitude | REAL |
| mag_w2 | W2 magnitude | REAL |
| mag_w3 | W3 magnitude | REAL |
| mag_w4 | W4 magnitude | REAL |
| mag_z | Converted Z magnitude | REAL |
| maskbits | bitwise mask indicating that an object touches a pixel in the coadd maskbits maps, as cataloged on the DR8 bitmasks page | SMALLINT |
| mjd_max | Maximum Modified Julian Date of observations used to construct the model of this object | DOUBLE |
| mjd_min | Minimum Modified Julian Date of observations used to construct the model of this object | DOUBLE |
| mw_transmission_g | Galactic transmission in g filter in linear units [0, 1] | REAL |
| mw_transmission_r | Galactic transmission in r filter in linear units [0, 1] | REAL |
| mw_transmission_w1 | Galactic transmission in W1 filter in linear units [0, 1] | REAL |
| mw_transmission_w2 | Galactic transmission in W2 filter in linear units [0, 1] | REAL |
| mw_transmission_w3 | Galactic transmission in W3 filter in linear units [0, 1] | REAL |
| mw_transmission_w4 | Galactic transmission in W4 filter in linear units [0, 1] | REAL |
| mw_transmission_z | Galactic transmission in z filter in linear units [0, 1] | REAL |
| nest4096 | HEALPIX index (Nsides 4096, Nest scheme => ~52 arcsec size | INTEGER |
| nobs_g | Number of images that contribute to the central pixel in g: filter for this object (not profile-weighted) | SMALLINT |
| nobs_r | Number of images that contribute to the central pixel in r: filter for this object (not profile-weighted) | SMALLINT |
| nobs_w1 | Number of images that contribute to the central pixel in W1: filter for this object (not profile-weighted) | SMALLINT |
| nobs_w2 | Number of images that contribute to the central pixel in W2: filter for this object (not profile-weighted) | SMALLINT |
| nobs_w3 | Number of images that contribute to the central pixel in W3: filter for this object (not profile-weighted) | SMALLINT |
| nobs_w4 | Number of images that contribute to the central pixel in W4: filter for this object (not profile-weighted) | SMALLINT |
| nobs_z | Number of images that contribute to the central pixel in z: filter for this object (not profile-weighted) | SMALLINT |
| objid | Catalog object number within this brick; a unique identifier hash is release,brickid,objid; objid spans [0,N-1] and is contiguously enumerated within each blob | INTEGER |
| parallax | Reference catalog parallax | REAL |
| parallax_ivar | Reference catalog inverse-variance on parallax | REAL |
| pmdec | Reference catalog proper motion in the Dec direction | REAL |
| pmdec_ivar | Reference catalog inverse-variance on pmdec | REAL |
| pmra | Reference catalog proper motion in the RA direction | REAL |
| pmra_ivar | Reference catalog inverse-variance on pmra | REAL |
| psfdepth_g | For a 5 sigma point source detection limit in g, 5/sqrt(psfdepth_g) gives flux in nanomaggies and -2.5[log_10(5 / sqrt(psfdepth_g)) - 9] gives corresponding AB magnitude | REAL |
| psfdepth_r | For a 5 sigma point source detection limit in g, 5/sqrt(psfdepth_r) gives flux in nanomaggies and -2.5[log_10(5 / sqrt(psfdepth_r)) - 9] gives corresponding AB magnitude | REAL |
| psfdepth_w1 | As for psfdepth_g (and also on the AB system) but for WISE W1 | REAL |
| psfdepth_w2 | As for psfdepth_g (and also on the AB system) but for WISE W2 | REAL |
| psfdepth_w3 | As for psfdepth_g (and also on the AB system) but for WISE W3 | REAL |
| psfdepth_w4 | As for psfdepth_g (and also on the AB system) but for WISE W4 | REAL |
| psfdepth_z | For a 5 sigma point source detection limit in g, 5/sqrt(psfdepth_z) gives flux in nanomaggies and -2.5[log_10(5 / sqrt(psfdepth_z)) - 9] gives corresponding AB magnitude | REAL |
| psfsize_g | Weighted average PSF FWHM in the g band | REAL |
| psfsize_r | Weighted average PSF FWHM in the r band | REAL |
| psfsize_z | Weighted average PSF FWHM in the z band | REAL |
| r_z | Computed (r-z) color | REAL |
| ra | Right ascension at equinox J2000 | DOUBLE |
| ra_ivar | Inverse variance of RA (no cosine term!), excluding astrometric calibration errors | REAL |
| random_id | Random ID in the range 0.0 => 100.0 | REAL |
| rchisq_g | Profile-weighted chi^2 of model fit normalized by the number of pixels in g | REAL |
| rchisq_r | Profile-weighted chi^2 of model fit normalized by the number of pixels in r | REAL |
| rchisq_w1 | Profile-weighted chi^2 of model fit normalized by the number of pixels in W1 | REAL |
| rchisq_w2 | Profile-weighted chi^2 of model fit normalized by the number of pixels in W2 | REAL |
| rchisq_w3 | Profile-weighted chi^2 of model fit normalized by the number of pixels in W3 | REAL |
| rchisq_w4 | Profile-weighted chi^2 of model fit normalized by the number of pixels in W4 | REAL |
| rchisq_z | Profile-weighted chi^2 of model fit normalized by the number of pixels in z | REAL |
| ref_cat | Reference catalog source for this star: T2 forTycho-2, G2 for Gaia DR2, L2 for the LSLGA, empty otherwise | VARCHAR |
| ref_epoch | Reference catalog reference epoch (eg, 2015.5 for Gaia DR2) | REAL |
| ref_id | Reference catalog identifier for this star; Tyc1*1,000,000+Tyc2*10+Tyc3 for Tycho2; sourceid for Gaia-DR2 and LSLGA | BIGINT |
| release | Unique integer denoting the camera and filter set used | SMALLINT |
| ring256 | HEALPIX index (Nsides 256, Ring scheme => ~14 arcmin size) | INTEGER |
| shapedev_e1 | Ellipticity component 1 | REAL |
| shapedev_e1_ivar | Inverse variance of shapedev_e1 | REAL |
| shapedev_e2 | Ellipticity component 2 | REAL |
| shapedev_e2_ivar | Inverse variance of shapedev_e2 | REAL |
| shapedev_r | Half-light radius of deVaucouleurs model (>0) | REAL |
| shapedev_r_ivar | Inverse variance of shapedev_r | REAL |
| shapeexp_e1 | Ellipticity component 1 | REAL |
| shapeexp_e1_ivar | Inverse variance of shapeexp_e1 | REAL |
| shapeexp_e2 | Ellipticity component 2 | REAL |
| shapeexp_e2_ivar | Inverse variance of shapeexp_e2 | REAL |
| shapeexp_r | Half-light radius of exponential model (>0) | REAL |
| shapeexp_r_ivar | Inverse variance of shapeexp_r | REAL |
| snr_g | Signal-to-Noise ratio in G | REAL |
| snr_r | Signal-to-Noise ratio in R | REAL |
| snr_w1 | Signal-to-Noise ratio in W1 | REAL |
| snr_w2 | Signal-to-Noise ratio in W2 | REAL |
| snr_w3 | Signal-to-Noise ratio in W3 | REAL |
| snr_w4 | Signal-to-Noise ratio in W4 | REAL |
| snr_z | Signal-to-Noise ratio in Z | REAL |
| type | Morphological model: PSF=stellar, REX=round exponential galaxy, DEV=deVauc, EXP=exponential, COMP=composite, DUP=Gaia source fit by different model. Note that in some FITS readers, a trailing space may be appended for PSF , DEV and EXP since the column data type is a 4-character string | VARCHAR |
| w1_w2 | Computed (w1-w2) color | REAL |
| w2_w3 | Computed (w2-w3) color | REAL |
| w3_w4 | Computed (w3-d4) color | REAL |
| wise_coadd_id | unWISE coadd file name for the center of each object | VARCHAR |
| wisemask_w1 | W1 bitmask as cataloged on the DR8 bitmasks page | SMALLINT |
| wisemask_w2 | W2 bitmask as cataloged on the DR8 bitmasks page | SMALLINT |
| z_w1 | Computed (z-w1 color | REAL |
