{"paper":{"title":"Improved constraints on the expansion rate of the Universe up to z~1.1 from the spectroscopic evolution of cosmic chronometers","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"A. Bongiorno, A. Cappi, A. Cimatti, A. Iovino, A. M. Koekemoer, A. Renzini, A. Stanford, B. Garilli, C. Diener, C. Knobel, C. L\\'opez-Sanjuan, C. Maier, C. M. Carollo, D. Stern, D. Vergani, E. Bradshaw, E. Perez-Montero, E. Zucca, F. Lamareille, G. Coppa, G. Zamorani, H. J. McCracken, H. Pearce, I. Balestra, J. D. Silverman, J. Dunlop, J.-F. Le Borgne, J.-P. Kneib, K. Caputi, K. Kovac, L. A. M. Tasca, L. Barnes, L. de Ravel, L. Pozzetti, L. Tresse, L. Verde, M. Bolzonella, M. Cirasuolo, M. Kamionkowski, M. Mignoli, M. Moresco, M. Scodeggio, M. Tanaka, N. Welikala, O. Almaini, O. Cucciati, O. Le Fevre, P. Franzetti, P. Kampczyk, P. Nair, P. Oesch, P. Rosati, Raul Jimenez, R. Bordoloi, R. Chuter, R. Gobat, R. McLure, R. Pell\\'o, S. Bardelli, S. de la Torre, S. Foucaud, S. J. Lilly, T. Contini, V. Le Brun, V. Mainieri, V. Presotto, W. Hartley, Y. Peng","submitted_at":"2012-01-17T20:19:31Z","abstract_excerpt":"We present new improved constraints on the Hubble parameter H(z) in the redshift range 0.15 < z < 1.1, obtained from the differential spectroscopic evolution of early-type galaxies as a function of redshift. We extract a large sample of early-type galaxies (\\sim11000) from several spectroscopic surveys, spanning almost 8 billion years of cosmic lookback time (0.15 < z < 1.42). We select the most massive, red elliptical galaxies, passively evolving and without signature of ongoing star formation. Those galaxies can be used as standard cosmic chronometers, as firstly proposed by Jimenez & Loeb ("},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1201.3609","kind":"arxiv","version":4},"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"}