{"paper":{"title":"A Cosmic Variance Cookbook","arxiv_id":"1001.1737","primary_cat":"astro-ph.CO","submitted_at":"2010-01-11T21:20:39+00:00","version_compiled":"v1"},"notice":"Every quoted sentence is the authors' text from the arXiv listing abstract. Labels and probabilities are the outputs of classifier-1.13-20260917 on the question bank abstract-p1-20260923, exactly as returned. No sentence in this record was written by a language model.","schema":"pith.compiled-record/v0","status":"compiled","abstract":{"source":"arXiv listing abstract v1","sentences":[{"i":0,"p":1.0,"id":"s0","own":false,"role":"background","text":"Deep pencil beam surveys (<1 deg^2) are of fundamental importance for studying the high-redshift universe.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.06,"main_claim_p":0.02,"quantitative":true,"quantitative_p":0.78,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.0,"background":1.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":1,"p":0.91,"id":"s1","own":false,"role":"background","text":"However, inferences about galaxy population properties are in practice limited by 'cosmic variance'.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.07,"main_claim_p":0.05,"quantitative":false,"quantitative_p":0.04,"role_probabilities":{"gap":0.02,"method":0.0,"result":0.0,"background":0.91,"limitation":0.07,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":2,"p":1.0,"id":"s2","own":false,"role":"background","text":"This is the uncertainty in observational estimates of the number density of galaxies arising from the underlying large-scale density fluctuations.","hedge":{"p":0.99,"label":"asserted"},"own_p":0.05,"main_claim_p":0.03,"quantitative":false,"quantitative_p":0.03,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.0,"background":1.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":3,"p":1.0,"id":"s3","own":false,"role":"background","text":"This source of uncertainty can be significant, especially for surveys which cover only small areas and for massive high-redshift galaxies.","hedge":{"p":0.82,"label":"asserted"},"own_p":0.09,"main_claim_p":0.08,"quantitative":false,"quantitative_p":0.11,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.0,"background":1.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":4,"p":0.82,"id":"s4","own":false,"role":"background","text":"Cosmic variance for a given galaxy population can be determined using predictions from cold dark matter theory and the galaxy bias.","hedge":{"p":0.97,"label":"asserted"},"own_p":0.08,"main_claim_p":0.04,"quantitative":false,"quantitative_p":0.03,"role_probabilities":{"gap":0.0,"method":0.17,"result":0.0,"background":0.82,"limitation":0.0,"future_work":0.0,"contribution":0.01,"interpretation":0.0}},{"i":5,"p":1.0,"id":"s5","own":true,"role":"contribution","text":"In this paper we provide tools for experiment design and interpretation.","hedge":{"p":0.97,"label":"asserted"},"own_p":0.86,"main_claim_p":0.06,"quantitative":false,"quantitative_p":0.03,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":1.0,"interpretation":0.0}},{"i":6,"p":0.89,"id":"s6","own":true,"role":"contribution","text":"For a given survey geometry we present the cosmic variance of dark matter as a function of mean redshift z and redshift bin size Dz.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.93,"main_claim_p":0.07,"quantitative":false,"quantitative_p":0.06,"role_probabilities":{"gap":0.0,"method":0.1,"result":0.01,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.89,"interpretation":0.0}},{"i":7,"p":0.96,"id":"s7","own":true,"role":"method","text":"Using a halo occupation model to predict galaxy clustering, we derive the galaxy bias as a function of mean redshift for galaxy samples of a given stellar mass range.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.94,"main_claim_p":0.04,"quantitative":false,"quantitative_p":0.05,"role_probabilities":{"gap":0.0,"method":0.96,"result":0.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.04,"interpretation":0.0}},{"i":8,"p":0.89,"id":"s8","own":false,"role":"method","text":"In the linear regime, the cosmic variance of these galaxy samples is the product of the galaxy bias and the dark matter cosmic variance.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.44,"main_claim_p":0.09,"quantitative":false,"quantitative_p":0.05,"role_probabilities":{"gap":0.0,"method":0.89,"result":0.01,"background":0.06,"limitation":0.0,"future_work":0.0,"contribution":0.04,"interpretation":0.0}},{"i":9,"p":0.51,"id":"s9","own":true,"role":"method","text":"We present a simple recipe using a fitting function to compute cosmic variance as a function of the angular dimensions of the field, z, Dz and stellar mass m*.","hedge":{"p":0.99,"label":"asserted"},"own_p":0.94,"main_claim_p":0.14,"quantitative":false,"quantitative_p":0.05,"role_probabilities":{"gap":0.0,"method":0.51,"result":0.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.49,"interpretation":0.0}},{"i":10,"p":0.98,"id":"s10","own":true,"role":"contribution","text":"We also provide tabulated values and a software tool.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.91,"main_claim_p":0.04,"quantitative":false,"quantitative_p":0.04,"role_probabilities":{"gap":0.0,"method":0.02,"result":0.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.98,"interpretation":0.0}},{"i":11,"p":1.0,"id":"s11","own":true,"role":"result","text":"We find that for GOODS at z=2 and with Dz=0.5 the relative cosmic variance of galaxies with m*>10^11 Msun is ~38%, while it is ~27% for GEMS and ~12% for COSMOS.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.94,"main_claim_p":0.2,"quantitative":true,"quantitative_p":0.99,"role_probabilities":{"gap":0.0,"method":0.0,"result":1.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":12,"p":1.0,"id":"s12","own":true,"role":"result","text":"For galaxies of m*~10^10 Msun the relative cosmic variance is ~19% for GOODS, ~13% for GEMS and ~6% for COSMOS.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.92,"main_claim_p":0.09,"quantitative":true,"quantitative_p":0.99,"role_probabilities":{"gap":0.0,"method":0.0,"result":1.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.0,"interpretation":0.0}},{"i":13,"p":1.0,"id":"s13","own":true,"role":"interpretation","text":"This implies that cosmic variance is a significant source of uncertainty at z=2 for small fields and massive galaxies, while for larger fields and intermediate mass galaxies cosmic variance is less 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