{"paper":{"title":"Keck Spectroscopy of z>1 Field Spheroidals: Dynamical Constraints on the Growth Rate of Red \"Nuggets\"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"Andrew B. Newman, Kevin Bundy, Richard S. Ellis, Tommaso Treu","submitted_at":"2010-04-08T13:23:15Z","abstract_excerpt":"We present deep Keck spectroscopy for 17 morphologically-selected field spheroidals in the redshift range 1.05<z<1.60 in order to investigate the continuity in physical properties between the claimed massive compact red galaxies (\"nuggets\") at z~2 and well-established data for massive spheroidal galaxies below z~1. By combining Keck-based stellar velocity dispersions with HST-based sizes, we find that the most massive systems (Mdyn > 10^11 Msol) grew in size over 0<z<1.6 as (1+z)^(-0.75 +- 0.10) (i.e., x2 since z=1.5) whereas intermediate mass systems (10^11 Msol > Mdyn > 10^10 Msol) did not g"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1004.1331","kind":"arxiv","version":2},"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"}