A Direct Constraint on the Gas Content of a Massive, Passively Evolving Elliptical Galaxy at z = 1.43

Author(s): Mark T. Sargent, Emanuele Daddi, Frederic Bournaud, M. Onodera, C. Fergulio, Helmut Dannerbauer
Abstract: Gas and dust in star-forming galaxies at the peak epoch of galaxy assembly are presently the topic of intense study, but little is known about the interstellar medium (ISM) of distant, passively evolving galaxies. We report on a deep 3 mm band search with the IRAM/Plateau de Bure Interferometer for molecular (H₂) gas in a massive ({{M}\star } ~ 6 × 10¹¹ {{M}_⊙ }) elliptical galaxy at z = 1.4277, the first observation of this kind ever attempted. We place a 3σ upper limit of 0.32 Jy km s_-1 on the flux of the CO(J = 2 \to 1) line or LCO^{\prime} < 8.8 × 10⁹ K km s^-1 pc², assuming a disklike CO-morphology and a circular velocity scaling with the stellar velocity dispersion as in local early-type galaxies (ETGs). This translates to an H2 mass of < 3.9 × 10¹⁰ ({α_CO}/4.4) {M_⊙} or a gas fraction of ≲6% assuming a Salpeter initial mass function and an ISM dominated by H₂, as observed in many local, high-mass ellipticals. This low value approaches that of local ETGs, suggesting that the low star formation activity in massive, high-z passive galaxies reflects a true dearth of gas and a lesser role for inhibitive mechanisms like morphological quenching.Based on observations with the Plateau de Bure Interferometer (PdBI), operated by the Institute for Radio Astronomy in the Millimeter range (IRAM), funded by a partnership of INSU/CNRS (France), MPG (Germany) and IGN (Spain).
Organisation(s): Department of Astrophysics
External organisation(s): University of Sussex, French Alternative Energies and Atomic Energy Commission (CEA), Eidgenössische Technische Hochschule Zürich, Institut de RadioAstronomie Millimétrique (IRAM), Scuola Normale Superiore di Pisa, INAF - Osservatorio Astronomico di Roma
Journal: The Astrophysical journal Letters
Volume: 806
No. of pages: 6
ISSN: 2041-8205
DOI: https://doi.org/10.1088/2041-8205/806/1/L20
Publication date: 06-2015
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/a-direct-constraint-on-the-gas-content-of-a-massive-passively-evolving-elliptical-galaxy-at-z--143(fad0d504-3b6e-4e9d-8fba-8bd8ebf5199d).html

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