TY - JOUR

T1 - Molecular gas in a gravitationally lensed galaxy group at z = 2.9

AU - Shen, Jeff

AU - Man, Allison W. S.

AU - Zabl, Johannes

AU - Zhang, Zhi-Yu

AU - Stockmann, Mikkel

AU - Brammer, Gabriel

AU - Whitaker, Katherine E.

AU - Richard, Johan

PY - 2021/8/19

Y1 - 2021/8/19

N2 - Most molecular gas studies of z > 2.5 galaxies are of intrinsically bright objects, despite the galaxy population being primarily normal galaxies with less extreme star formation rates. Observations of normal galaxies at high redshift provide a more representative view of galaxy evolution and star formation, but such observations are challenging to obtain. In this work, we present Atacama Large Millimeter/submillimeter Array (CO)-C-12(J = 3 -> 2) observations of a submillimeter selected galaxy group at z = 2.9, resulting in spectroscopic confirmation of seven images from four member galaxies. These galaxies are strongly lensed by the MS 0451.6-0305 foreground cluster at z = 0.55, allowing us to probe the molecular gas content on levels of 10(9)-10(10) M (circle dot). Four detected galaxies have molecular gas masses of (0.2-13.1) x 10(10) M (circle dot), and the nondetected galaxies have inferred molecular gas masses of M (circle dot). We compare these new data to a compilation of 546 galaxies up to z = 5.3, and find that depletion times decrease with increasing redshift. We then compare the depletion times of galaxies in overdense environments to the field-scaling relation from the literature, and find that the depletion time evolution is steeper for galaxies in overdense environments than for those in the field. More molecular gas measurements of normal galaxies in overdense environments at higher redshifts (z > 2.5) are needed to verify the environmental dependence of star formation and gas depletion.

AB - Most molecular gas studies of z > 2.5 galaxies are of intrinsically bright objects, despite the galaxy population being primarily normal galaxies with less extreme star formation rates. Observations of normal galaxies at high redshift provide a more representative view of galaxy evolution and star formation, but such observations are challenging to obtain. In this work, we present Atacama Large Millimeter/submillimeter Array (CO)-C-12(J = 3 -> 2) observations of a submillimeter selected galaxy group at z = 2.9, resulting in spectroscopic confirmation of seven images from four member galaxies. These galaxies are strongly lensed by the MS 0451.6-0305 foreground cluster at z = 0.55, allowing us to probe the molecular gas content on levels of 10(9)-10(10) M (circle dot). Four detected galaxies have molecular gas masses of (0.2-13.1) x 10(10) M (circle dot), and the nondetected galaxies have inferred molecular gas masses of M (circle dot). We compare these new data to a compilation of 546 galaxies up to z = 5.3, and find that depletion times decrease with increasing redshift. We then compare the depletion times of galaxies in overdense environments to the field-scaling relation from the literature, and find that the depletion time evolution is steeper for galaxies in overdense environments than for those in the field. More molecular gas measurements of normal galaxies in overdense environments at higher redshifts (z > 2.5) are needed to verify the environmental dependence of star formation and gas depletion.

KW - FORMATION-DENSITY RELATION

KW - STAR-FORMING GALAXY

KW - SUBMILLIMETER GALAXY

KW - PHYSICAL-PROPERTIES

KW - INTERSTELLAR-MEDIUM

KW - SCALING RELATIONS

KW - DATA RELEASE

KW - CLUSTER

KW - REDSHIFT

KW - EVOLUTION

U2 - 10.3847/1538-4357/ac0435

DO - 10.3847/1538-4357/ac0435

M3 - Journal article

VL - 917

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 79

ER -