A z = 1.82 ANALOG OF LOCAL ULTRA-MASSIVE ELLIPTICAL GALAXIES

Journal Article · Thu May 20 04:00:00 EDT 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/715/1/L6· OSTI ID:21448776

Onodera, M; Daddi, E; Gobat, R ^[1]; Cappellari, M ^[2]; Arimoto, N; Yamada, Y ^[3]; Renzini, A; Mancini, C ^[4]; McCracken, H J ^[5]; Capak, P ^[6]; Carollo, M; Lilly, S ^[7]; Cimatti, A ^[8]; Giavalisco, M ^[9]; Ilbert, O ^[10]; Kong, X ^[11]; Motohara, K ^[12]; Ohta, K ^[13]; Sanders, D B ^[14]; Scoville, N ^[15]

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1. CEA, Laboratoire AIM-CNRS-Universite Paris Diderot, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France)
2. Sub-department of Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom)
3. National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo (Japan)
4. INAF-Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova (Italy)
5. Institut d'Astrophysique de Paris, UMR7095, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, 75014 Paris (France)
6. Spitzer Science Center, California Institute of Technology 220-06, Pasadena, CA 91125 (United States)
7. Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-strasse 27, 8093 Zurich (Switzerland)
8. Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, 40127 Bologna (Italy)
9. Department of Astronomy, University of Massachusetts, Amherst, MA (United States)
10. Laboratoire d'Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille Cedex 12 (France)
11. Center for Astrophysics, University of Science and Technology of China, Hefei, Anhui 230026 (China)
12. Institute of Astronomy, University of Tokyo, Mitaka, Tokyo (Japan)
13. Department of Astronomy, Kyoto University, Kyoto 606-8502 (Japan)
14. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
15. California Institute of Technology, MC 105-24, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

We present observations of a very massive galaxy at z = 1.82 that show that its morphology, size, velocity dispersion, and stellar population properties are fully consistent with those expected for passively evolving progenitors of today's giant ellipticals. These findings are based on a deep optical rest-frame spectrum obtained with the Multi-Object InfraRed Camera and Spectrograph on the Subaru Telescope of a high-z passive galaxy candidate (pBzK) from the COSMOS field, for which we accurately measure its redshift of z = 1.8230 and obtain an upper limit on its velocity dispersion {sigma}{sub *} < 326 km s{sup -1}. By detailed stellar population modeling of both the galaxy broadband spectral energy distribution and the rest-frame optical spectrum, we derive a star formation-weighted age and formation redshift of t {sub sf} {approx_equal} 1-2 Gyr and z {sub form} {approx_equal} 2.5-4, and a stellar mass of M {sub *} {approx_equal} (3-4) x 10{sup 11} M {sub sun}. This is in agreement with a virial mass limit of M {sub vir} < 7 x 10{sup 11} M {sub sun}, derived from the measured {sigma}{sub *} value and stellar half-light radius, as well as with the dynamical mass limit based on the Jeans equations. In contrast to previously reported super-dense passive galaxies at z {approx} 2, the present galaxy at z = 1.82 appears to have both size and velocity dispersion similar to early-type galaxies in the local universe with similar stellar mass. This suggests that z {approx} 2 massive and passive galaxies may exhibit a wide range of properties, then possibly following quite different evolutionary histories from z {approx} 2 to z = 0.

• OSTI ID: 21448776
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 715; ISSN 2041-8205
• Country of Publication: United States
• Language: English

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