{"paper":{"title":"The ALHAMBRA survey: an empirical estimation of the cosmic variance for merger fraction studies based on close pairs","license":"http://creativecommons.org/licenses/by-nc-sa/3.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"A. Del Olmo, A. Fern\\'andez-Soto, A. J. Cenarro, A. Molino, B. Ascaso, C. Hern\\'andez-Monteagudo, C. Husillos, C. L\\'opez-Sanjuan, D. Crist\\'obal-Hornillos, E. Alfaro, F. J. Castander, F. Prada, I. M\\'arquez, J. A. L. Aguerri, J. Cabrera-Ca\\~no, J. Cepa, J. Masegosa, J. M. Quintana, J. Perea, J. Varela, L. Infante, M. Cervi\\~no, M. Huertas-Company, M. Moles, M. Povi\\'c, N. Ben\\'itez, P. Arnalte-Mur, R. M. Gonz\\'alez Delgado, T. Broadhurst, V. J. Mart\\'inez","submitted_at":"2014-01-20T17:30:12Z","abstract_excerpt":"Our goal is to estimate empirically, for the first time, the cosmic variance that affects merger fraction studies based on close pairs. We compute the merger fraction from photometric redshift close pairs with 10h^-1 kpc <= rp <= 50h^-1 kpc and Dv <= 500 km/s, and measure it in the 48 sub-fields of the ALHAMBRA survey. We study the distribution of the measured merger fractions, that follow a log-normal function, and estimate the cosmic variance sigma_v as the intrinsic dispersion of the observed distribution. We develop a maximum likelihood estimator to measure a reliable sigma_v and avoid the"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1401.4993","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}