{"work":{"id":"e2a6db9e-0bd0-461e-83c0-2c5f902fbf5c","openalex_id":"https://openalex.org/W2167335950","doi":"10.1051/0004-6361:20065138","arxiv_id":"astro-ph/0603217","raw_key":null,"title":"Accurate photometric redshifts for the CFHT Legacy Survey calibrated using the VIMOS VLT Deep Survey","authors":[{"given":"O.","family":"Ilbert","sequence":"first","affiliation":[]},{"given":"S.","family":"Arnouts","sequence":"additional","affiliation":[]},{"given":"H. 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We use 3241 spectroscopic redshifts with 0<z<5 from the VIMOS VLT Deep Survey as a calibration to derive these photometric redshifts. We devise a robust calibration method which removes systematic trends in the photometric redshifts and significantly reduces the fraction of catastrophic errors. We use our unique spectroscopic sample to present a detailed assessment of the robustness of the photometric redshift sample. For a sample selected at i'_{AB}<24, we reach a redshift accuracy of \\sigma_{\\Delta z/(1+z)}=0.037 with \\eta=3.7% of catastrophic error. The reliability of our photometric redshifts is lower for fainter objects: we find \\sigma_{\\Delta z/(1+z)}=0.029, 0.043 and \\eta=1.7%, 5.4% for samples selected at i'_{AB}=17.5-22.5 and 22.5-24 respectively. We find that the photometric redshifts of starburst galaxies in our sample are less reliable: although these galaxies represent only 18% of the spectroscopic sample they are responsible for 54% of the catastrophic errors. We find an excellent agreement between the photometric and the VVDS spectroscopic redshift distributions at i'_{AB}<24. Finally, we compare the redshift distributions of i' selected galaxies on the four CFHTLS deep fields, showing that cosmic variance is already present on fields of 0.8 deg^2.","external_url":"https://arxiv.org/abs/astro-ph/0603217","cited_by_count":1437,"metadata_source":"pith","metadata_fetched_at":"2026-05-25T03:55:19.402497+00:00","pith_arxiv_id":"astro-ph/0603217","created_at":"2026-05-08T18:18:55.661737+00:00","updated_at":"2026-05-25T03:55:19.402497+00:00","title_quality_ok":true,"display_title":"J., et al","render_title":"J., et al"},"hub":{"state":{"work_id":"e2a6db9e-0bd0-461e-83c0-2c5f902fbf5c","tier":"hub","tier_reason":"10+ Pith inbound or 1,000+ external citations","pith_inbound_count":19,"external_cited_by_count":1437,"distinct_field_count":4,"first_pith_cited_at":"2021-12-07T17:57:21+00:00","last_pith_cited_at":"2026-05-22T12:19:56+00:00","author_build_status":"not_needed","summary_status":"needed","contexts_status":"needed","graph_status":"needed","ask_index_status":"not_needed","reader_status":"not_needed","recognition_status":"not_needed","updated_at":"2026-05-30T11:11:13.534681+00:00","tier_text":"hub"},"tier":"hub","role_counts":[{"context_role":"background","n":1},{"context_role":"method","n":1}],"polarity_counts":[{"context_polarity":"background","n":1},{"context_polarity":"use_method","n":1}],"runs":{},"summary":{},"graph":{},"authors":[]}}