TY - JOUR
T1 - A direct constraint on the gas content of a massive, passively evolving elliptical galaxy at z = 1.43
AU - Sargent, M. T.
AU - Daddi, E.
AU - Bournaud, F.
AU - Onodera, M.
AU - Feruglio, C.
AU - Martig, M.
AU - GOBAT , RAPHAEL ALEXANDRE SIMON
AU - Dannerbauer, H.
AU - Schinnerer, E.
PY - 2015/6/10
Y1 - 2015/6/10
N2 - 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∗∼ 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 → 1) line or < 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 (αCO/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.
AB - 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∗∼ 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 → 1) line or < 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 (αCO/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.
KW - cosmology: observations
KW - galaxies: elliptical and lenticular cD
KW - galaxies: evolution
KW - galaxies: ISM
KW - ISM: molecules
UR - http://www.scopus.com/inward/record.url?scp=84930936339&partnerID=8YFLogxK
U2 - 10.1088/2041-8205/806/1/L20
DO - 10.1088/2041-8205/806/1/L20
M3 - Article
AN - SCOPUS:84930936339
VL - 806
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
SN - 2041-8205
IS - 1
M1 - L20
ER -