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Table: des_sva1.gold_ngmix
(The bold columns are indexed columns)
| Column Name | Description | Datatype |
|---|---|---|
| arate | Acceptance rate. Galaxies with 0.4 < ARATE < 0.6 are considered good. | REAL |
| coadd_objects_id | Unique object identifier (can be used to match against other SVA1 catalogs) | BIGINT |
| e_1 | The raw (biased) shear estimator. | DOUBLE |
| e_2 | The raw (biased) shear estimator. | DOUBLE |
| e_cov_1_1 | The estimated covariance matrix of (E_1, E_2). | DOUBLE |
| e_cov_1_2 | The estimated covariance matrix of (E_1, E_2). | DOUBLE |
| e_cov_2_1 | The estimated covariance matrix of (E_1, E_2). | DOUBLE |
| e_cov_2_2 | The estimated covariance matrix of (E_1, E_2). | DOUBLE |
| error_flag | A flag describing potential problems with the shear estimate. Only objects with ERROR_FLAG == 0 should be used for any scientific analysis. | INTEGER |
| flux_i | An estimate of the i-band flux that comes out of the same fitting process as was used for the shapes. This should only be used as a diagnostic. For accurate, calibrated fluxes, users should use the flux values in the Gold catalogs. | REAL |
| log10_sb_i | The base 10 logarithm of an estimate of the surface brightness of the object in units of (ADU / arcsec^2). This is a derived value, calculated as log10(abs(FLUX_I / T)). | REAL |
| mag_i | An estimate of the i-band magnitude that comes out of the same fitting process as was used for the shapes. This should only be used as a diagnostic. For accurate, calibrated fluxes, users should use the flux values in the Gold catalogs. | REAL |
| mask_frac | The fraction of the pixels in all the postage stamps used for this galaxy that were masked for some reason (neighboring objects, dead pixels, bad columns, cosmic rays, etc.) | REAL |
| mean_psf_e1 | The mean measured ellipticity and size of the PSF for the different exposures that went into the shear estimates for this galaxy. | DOUBLE |
| mean_psf_e2 | The mean measured ellipticity and size of the PSF for the different exposures that went into the shear estimates for this galaxy. | DOUBLE |
| mean_psf_t | The mean measured ellipticity and size of the PSF for the different exposures that went into the shear estimates for this galaxy. | REAL |
| sens_1 | The raw sensitivity estimate for E_1. We recommend using SENS_AVG, which is the average of SENS_1 and SENS_2, for both E_1 and E_2, rather than these individual estimates. | REAL |
| sens_2 | The raw sensitivity estimate for E_2. We recommend using SENS_AVG, which is the average of SENS_1 and SENS_2, for both E_1 and E_2, rather than these individual estimates. | REAL |
| sens_avg | The sensitivity estimate. See Section 9.2 of Jarvis et al, 2015 for instructions on how the sensitivity should be applied to an ensemble of galaxies. | DOUBLE |
| snr_r | The roundified S/N estimate. See Section 7.1 of Jarvis et al, 2015 for an explanation of the differences between SNR_W and SNR_R estimates. In particular, it is recommended that any selection involving S/N beyond the cuts we have already applied should use SNR_W, not SNR_R. (This is different for im3shape!) | REAL |
| snr_t | The estimated S/N of T. | REAL |
| snr_t_r | The estimated S/N of T_R. | REAL |
| snr_w | The standard optimal weight S/N estimate. See Section 7.1 of Jarvis et al, 2015 for an explanation of the differences between SNR_W and SNR_R estimates. In particular, it is recommended that any selection involving S/N beyond the cuts we have already applied should use SNR_W, not SNR_R. (This is different for im3shape!) | REAL |
| stamp_size | The size (in pixels) of the postage stamp images used for this galaxy. | INTEGER |
| t | An estimate of the size, using the T = Ixx + Iyy definition of size, in arcsec^2. See Section 8.3.2 in Jarvis et al, 2015 for a description of the difference between T and T_R size estimates. In particular, the formula for T_R is Eqn. 8.4. It is recommended that any selection involving size beyond the cuts we have already applied should use T_R, not T. | REAL |
| t_err | The estimated uncertainty in the estimate of T. | REAL |
| t_r | An estimate of the size that the object would have had if it were round. See Section 8.3.2 in Jarvis et al, 2015 for a description of the difference between T and T_R size estimates. In particular, the formula for T_R is Eqn. 8.4. It is recommended that any selection involving size beyond the cuts we have already applied should use T_R, not T. | REAL |
| w | The recommended weight to use for each galaxy. See Eqn 7.12 in Jarvis et al, 2015 for the exact definition of this choice. | DOUBLE |
