KiDZ redshift calibration sample
Redshift distributions for the KiDS-Legacy weak lensing sample are estimated and calibrated using the methods and simulations described in Wright, Hildebrandt, van den Busch, et al 2026. Redshift distribution estimates are computed using reference spectroscopic samples of galaxies which fall within the KiDZ footprint, described in the DR5 release manuscript Wright, Kuijken, Hildebrandt, Radovich, Bilicki et al 2024. The KiDZ photometric data are released alongside the main KiDS-DR5 sample.
Download the Legacy-KiDZ redshift calibration sample
The application of the KiDZ data to the KiDS-Legacy weak lensing sample necessitates a down-sampling of the full catalogue (due to, e.g., photometric redshift limits). Additionally, the spectroscopic sample is weighted in a number of ways, to ensure robust redshift distribution inference. These weightings include an a-priori matching of the redshift-space frequency of spectra to an analytic distribution that approximates KiDS-Legacy (‘prior volume weight’), weighting spectra for shape-measurement confidence (’shape weight’), and weighting sources to be representative of the KiDS-Legacy colour space (‘gold weight’). The final catalogue contains a total of 77,014 high-confidence spectra, with weights (‘final weight’) that are used to produce an N(z) for each tomographic bin, presented as a single FITS table.
→ Catalogue: KiDZ_Legacy_unblind_final.fits
→ Column descriptions: KiDZ_Legacy_unblind_final.readme.txt
| Column | Unit | Description | Format |
|---|---|---|---|
| RAJ2000 | deg | Centroid sky position right ascension (J2000) (deg) | 1D |
| DECJ2000 | deg | Centroid sky position declination (J2000) (deg) | 1D |
| Level | count | Detection threshold above background (count) | 1E |
| FLUX_RADIUS | pixel | Half-light radius (pix) | 1E |
| Agaper | arcsec | Major axis of GAaP aperture optimal min_aper (arcsec) | 1E |
| Bgaper | arcsec | Minor axis of GAaP aperture optimal min_aper (arcsec) | 1E |
| MAG_AUTO | mag | r-band magnitude | 1E |
| MAG_GAAP_u | mag | u-band GAaP magnitude optimal min_aper | 1E |
| MAG_GAAP_g | mag | g-band GAaP magnitude optimal min_aper | 1E |
| MAG_GAAP_r | mag | r-band GAaP magnitude optimal min_aper | 1E |
| MAG_GAAP_i1 | mag | i-band GAaP magnitude optimal min_aper, from first pass | 1E |
| MAG_GAAP_i2 | mag | i-band GAaP magnitude optimal min_aper, from second pass | 1E |
| MAG_GAAP_Z | mag | Z-band GAaP magnitude optimal min_aper | 1E |
| MAG_GAAP_Y | mag | Y-band GAaP magnitude optimal min_aper | 1E |
| MAG_GAAP_J | mag | J-band GAaP magnitude optimal min_aper | 1E |
| MAG_GAAP_H | mag | H-band GAaP magnitude optimal min_aper | 1E |
| MAG_GAAP_Ks | mag | Ks-band GAaP magnitude optimal min_aper | 1E |
| Z_B | 9-band BPZ redshift estimate; peak of posterior probability distribution | 1D | |
| T_B | Spectral type corresponding to Z_B | 1D | |
| TOMOBIN | Tomographic bin index | 1I | |
| z_spec | Spectroscopic redshift, drawn from KiDZ compilation | 1E | |
| prior_volume_weight_only | Component of final_weight coming from prior volume reweighting | 1E | |
| shape_weight_only | Component of final_weight coming from source shape measurement | 1E | |
| gold_weight_only | Component of final_weight coming from gold classification | 1E | |
| final_weight | Combined weight used (with z_spec) in computation of tomographic N(z) | 1E |