Photometric redshifts for the CFHTLS T0004 deep and wide fields

By Jean Coupon, O. Ilbert, M. Kilbinger, H. McCracken, Y. Mellier, Stéphane Arnouts, E. Bertin, P. Hudelot, M. Schultheis, O. Fèvre and 10 more. 2008

156 citations recorded by the source corpus.

We compute photometric redshifts based on the template-fitting method in the fourth public release of the Canada-France-Hawaii Telescope Legacy Survey. This unique multi-colour catalogue comprises u*,g',r',i',z' photometry in four deep fields of 1 deg2 each and 35 deg2 distributed over three Wide fields. Our photometric redshifts are calibrated with and compared to 16,983 high-quality spectroscopic redshifts from several surveys. We find a dispersion of 0.028 and an outlier rate of 3.5% in the Deep field at i'AB < 24 and a dispersion of 0.036 and an outlier rate of 2.8% in the Wide field at i'AB < 22.5. Beyond i'AB = 22.5 in the Wide field the number of outliers rises from 5% to 10% at i'AB<23 and i'AB<24 respectively. For the Wide sample, we find the systematic redshift bias keeps below 1% to i'AB < 22.5, whereas we find no significant bias in the Deep field. We investigated the effect of tile-to-tile photometric variations and demonstrate that the accuracy of our photometric redshifts is reduced by at most 21%. We separate stars from galaxies using both the size and colour information, reducing the contamination by stars in our catalogues from 50% to 8% at i'AB < 22.5 in fields with the highest stellar density while keeping a complete galaxy sample. Our CFHTLS T0004 photometric redshifts are distributed to the community. Our release include 592,891 (i'AB < 22.5) and 244,701 (i'AB < 24) reliable galaxy photometric redshifts in the Wide and Deep fields, respectively.

Subfields: Astronomy and Astrophysics, Ecology, Instrumentation

View Paper: https://www.semanticscholar.org/paper/6964898f7a0009b1fa7d132c97c8fb967acb92b3

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Citations in the corpus

CFHTLenS: Improving the quality of photometric redshifts with precision photometry (2011, methodology): “It has been suggested in the literature (e.g. Coe et al. 2006; Ilbert et al. 2006; Coupon et al. 2009) that a re-calibration of the photometric zeropoints of the images with the help of spec-z’s can lead to an enhanced accuracy of photo-z’s.”
THE PRISM MULTI-OBJECT SURVEY (PRIMUS). I. SURVEY OVERVIEW AND CHARACTERISTICS (2010, background): “This scaling means that even widefield photometric surveys are highly inefficient, and the current best photometric redshift surveys over wide areas have a precision of 3-4% (CFHTLS, Coupon et al. 2009).”
The many flavours of photometric redshifts (2018, background): “perform better than those having only broad band photometry (WIRDS: [132]; CFHTLS WIDE: [89]; KiDS: [133]; SDSS:[82]; DES: [85]).”
CFHTLenS: the Canada–France–Hawaii Telescope Lensing Survey – imaging data and catalogue products (2012, methodology): “In addition a problem with the redshift-scaling of the two-point shear correlation function soon became apparent when the data used in Fu et al. (2008) were combined with photometric redshift measurements from Coupon et al. (2009), (see Kilbinger et al. 2009, for more details).”
THE BARYON OSCILLATION SPECTROSCOPIC SURVEY OF SDSS-III (2012, methodology): “The galaxy targets were color-selected based on the CFHT-LS photometric-redshift catalog (Coupon et al. 2009).”
Galaxy clustering in the CFHTLS-Wide: the changing relationship between galaxies and haloes since z ~ 1.2 (2011, methodology): “…errors could affect our results as function of redshift and luminosity threshold, we compared our measurements in the CFHTLS Wide with those from the “Deep” component of the CFHTLS (Goranova et al. 2009), where more precise photometric redshifts are available (see Table 3 in Coupon et al. 2009).”
The Subaru FMOS galaxy redshift survey (FastSound). IV. New constraint on gravity theory from redshift space distortions at z ∼ 1.4 (2015, unknown): “(Ilbert et al. 2006; Coupon et al. 2009; Goranova et al. 20094; Gwyn 2012; Paper I ).”
COSMOS2020: A Panchromatic View of the Universe to z ∼ 10 from Two Complementary Catalogs (2021, background): “This criterion is applied only for sources detected at 3σ in the Ks band or the IRAC channel 1, since the lack of near-infrared data could increase the risk of stellar contamination in the galaxy sample (Daddi et al. 2004; Coupon et al. 2009).”