Measuring the gas reservoirs in 10^8< M_⋆<10^11 M_⊙ galaxies at 1≤ z≤3

Understanding the gas content in galaxies, its consumption and replenishment, remains pivotal in our comprehension of the evolution of the Universe. Numerous studies have addressed this, utilizing various observational tools and analytical methods. These include examining low-transition ^12CO millimeter rotational lines and exploring the far-infrared and the (sub-)millimeter emission of galaxies. With the capabilities of present-day facilities, much of this research has been centered on relatively bright galaxies. We aim at exploring the gas reservoirs of a more general type of galaxy population at 1.0≤ z≤ 3.0. We stack ALMA 1.1 mm data to measure the gas content of a mass-complete sample down to ∼10^8.6 M_⊙ at z=1 (∼10^9.2 M_⊙ at z=3), extracted from the HST/CANDELS sample in GOODS-S. The sample is composed of 5,530 on average blue (∼0.12 mag, ∼0.81 mag), star-forming main sequence objects (ΔMS∼-0.03). We report measurements at 10^10-11 M_⊙ and upper limits for the gas fractions at 10^8-10 M_⊙. At 10^10-11 M_⊙, our f_gas, ranging from 0.32 to 0.48, agree well with other studies based on mass-complete samples down to 10^10 M_⊙, and are lower than expected according to other works more biased to individual detections. At 10^9-10 M_⊙, we obtain 3σ upper limits for f_gas ranging from 0.69 to 0.77. These upper limits are on the level of the extrapolations of scaling relations based on mass-complete samples down to 10^10 M_⊙. As such, it suggests that the gas content of low-mass galaxies is at most what is extrapolated from literature scaling relations. The comparison of our results with previous works reflects how the inclusion of bluer, less obscured, and more MS-like objects progressively pushes the gas level to lower values.