Rights statement: This is an author-created, un-copyedited version of an article accepted for publication/published in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi:10.3847/1538-4357/aac438
Accepted author manuscript, 7.41 MB, PDF document
Available under license: CC BY-NC: Creative Commons Attribution-NonCommercial 4.0 International License
Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Molecular gas contents and scaling relations for massive passive galaxies at intermediate redshifts from the LEGA-C survey
AU - Spilker, Justin
AU - Bezanson, Rachel
AU - Barišić, Ivana
AU - Lagos, Claudia
AU - Maseda, Michael V.
AU - Muzzin, Adam
AU - Pacifici, Camilla
AU - Sobral, David
AU - Straatman, Caroline
AU - Wel, Arjen van der
AU - Dokkum, Pieter G. van
AU - Weiner, Benjamin
AU - Whitaker, Katherine
AU - Williams, Christina
AU - Wu, Po-Feng
N1 - This is an author-created, un-copyedited version of an article accepted for publication/published in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi:10.3847/1538-4357/aac438
PY - 2018/6/18
Y1 - 2018/6/18
N2 - Significant observational resources have been dedicated over the last decade to understanding the interplay between molecular gas, star formation, and stellar growth in star-forming galaxies out to z ∼ 3. Passive galaxies, however, are expected to be gas-poor and therefore faint, and thus little is known about molecular gas in passive galaxies beyond the local universe. Here we present deep Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO(2–1) emission in 8 massive (Mstar ∼ 10^11 M⊙) galaxies at z ∼ 0.7 selected to lie a factor of 3–10 below the star-forming sequence at this redshift, drawn from the Large Early Galaxy Astrophysics Census (LEGA-C) survey. We significantly detect half the sample, finding molecular gas fractions ﰁ 0.1. We show that the molecular and stellar rotational axes are broadly consistent, arguing that the molecular gas was not accreted after the galaxies became quiescent. We find that scaling relations extrapolated from the star-forming population over- predict both the gas fraction and gas depletion time for passive objects, suggesting the existence of either a break or large increase in scatter in these relations at low specific star formation rate. Finally, we show that the gas fractions of the passive galaxies we have observed at intermediate redshifts are naturally consistent with evolution into local massive early-type galaxies by continued low-level star formation, with no need for further gas accretion or dynamical stabilization of the gas reservoirs in the intervening 6 billion years.
AB - Significant observational resources have been dedicated over the last decade to understanding the interplay between molecular gas, star formation, and stellar growth in star-forming galaxies out to z ∼ 3. Passive galaxies, however, are expected to be gas-poor and therefore faint, and thus little is known about molecular gas in passive galaxies beyond the local universe. Here we present deep Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO(2–1) emission in 8 massive (Mstar ∼ 10^11 M⊙) galaxies at z ∼ 0.7 selected to lie a factor of 3–10 below the star-forming sequence at this redshift, drawn from the Large Early Galaxy Astrophysics Census (LEGA-C) survey. We significantly detect half the sample, finding molecular gas fractions ﰁ 0.1. We show that the molecular and stellar rotational axes are broadly consistent, arguing that the molecular gas was not accreted after the galaxies became quiescent. We find that scaling relations extrapolated from the star-forming population over- predict both the gas fraction and gas depletion time for passive objects, suggesting the existence of either a break or large increase in scatter in these relations at low specific star formation rate. Finally, we show that the gas fractions of the passive galaxies we have observed at intermediate redshifts are naturally consistent with evolution into local massive early-type galaxies by continued low-level star formation, with no need for further gas accretion or dynamical stabilization of the gas reservoirs in the intervening 6 billion years.
U2 - 10.3847/1538-4357/aac438
DO - 10.3847/1538-4357/aac438
M3 - Journal article
VL - 860
JO - The Astrophysical Journal
JF - The Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 103
ER -