{"paper":{"title":"A direct measurement of hierarchical growth in galaxy groups since z~1","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"Alan Dressler, Daniel D. Kelson, John S. Mulchaey, Patrick J. McCarthy, Rik J. Williams, Stephen A. Shectman (Carnegie Observatories)","submitted_at":"2012-01-04T21:11:00Z","abstract_excerpt":"We present the first measurement of the evolution of the galaxy group stellar mass function (GrSMF) to redshift z>~1 and low masses (M*>10^12 Msun). Our results are based on early data from the Carnegie-Spitzer-IMACS (CSI) Survey, utilizing low-resolution spectra and broadband optical/near-IR photometry to measure redshifts for a 3.6um selected sample of 37,000 galaxies over a 5.3 deg^2 area to z~1.2. Employing a standard friends-of-friends algorithm for all galaxies more massive than log(M*/Msun)=10.5, we find a total of ~4000 groups. Correcting for spectroscopic incompleteness (including sli"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1201.1009","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"}