ALMA Observations of Gas-Rich Galaxies in z~1.6 Galaxy Clusters: Evidence for Higher Gas Fractions in High-Density Environments

Abstract

We present ALMA CO (2-1) detections in 11 gas-rich cluster galaxies at z~1.6, constituting the largest sample of molecular gas measurements in z>1.5 clusters to date. The observations span three galaxy clusters, derived from the Spitzer Adaptation of the Red-sequence Cluster Survey. We augment the >5sigma detections of the CO (2-1) fluxes with multi-band photometry, yielding stellar masses and infrared-derived star formation rates, to place some of the first constraints on molecular gas properties in z~1.6 cluster environments. We measure sizable gas reservoirs of 0.5-2x10^11 solar masses in these objects, with high gas fractions and long depletion timescales, averaging 62% and 1.4 Gyr, respectively. We compare our cluster galaxies to the scaling relations of the coeval field, in the context of how gas fractions and depletion timescales vary with respect to the star-forming main sequence. We find that our cluster galaxies lie systematically off the field scaling relations at z=1.6 toward enhanced gas fractions, at a level of ~4sigma, but have consistent depletion timescales. Exploiting CO detections in lower-redshift clusters from the literature, we investigate the evolution of the gas fraction in cluster galaxies, finding it to mimic the strong rise with redshift in the field. We emphasize the utility of detecting abundant gas-rich galaxies in high-redshift clusters, deeming them as crucial laboratories for future statistical studies.

8 pages, 3 figures, published in ApJ Letters; updated to match published version

References in corpus (12)

• Combined CO & Dust Scaling Relations of Depletion Time and Molecular Gas Fractions with Cosmic Time, Specific Star Formation Rate and Stellar Mass
• COLD GASS, an IRAM Legacy Survey of Molecular Gas in Massive Galaxies: II. The non-universality of the Molecular Gas Depletion Timescale
• CO excitation of normal star forming galaxies out to z=1.5 as regulated by the properties of their interstellar medium
• Molecular and atomic gas along and across the main sequence of star-forming galaxies
• BUDHIES II: A phase-space view of HI gas stripping and star-formation quenching in cluster galaxies
• Star formation quenching in simulated group and cluster galaxies: When, how, and why?
• The Role of Environment in the Mass-Metallicity Relation
• ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Molecular gas reservoirs in high-redshift galaxies
• Stellar mass function of cluster galaxies at z $\sim$ 1.5: evidence for reduced quenching efficiency at high redshift
• Evolution of the atomic and molecular gas content of galaxies in dark matter haloes
• Chandra deep observation of XDCP J0044.0-2033, a massive galaxy cluster at z>1.5
• Evolutionary phases of gas-rich galaxies in a galaxy cluster at z=1.46

Cited by in corpus (45)

• The Evolution of the Star-forming Interstellar Medium across Cosmic Time
• Deep CO(1-0) Observations of z=1.62 Cluster Galaxies with Substantial Molecular Gas Reservoirs and Normal Star Formation Efficiencies
• Confirming Herschel candidate protoclusters from ALMA/VLA CO observations
• Environmental impacts on molecular gas in protocluster galaxies at z~2
• Emergence of an Ultra-Red Ultra-Massive Galaxy Cluster Core at $z=4$
• On the Gas Content, Star Formation Efficiency, and Environmental Quenching of Massive Galaxies in Proto-Clusters at z~2.0-2.5
• The ALMA-ALPAKA survey I: high-resolution CO and [CI] kinematics of star-forming galaxies at z = 0.5-3.5
• COALAS: I. ATCA CO(1-0) survey and luminosity function in the Spiderweb protocluster at z=2.16
• Spectroscopic Confirmation of a Coma Cluster Progenitor at z ~ 2.2
• Molecular hydrogen in IllustrisTNG galaxies: carefully comparing signatures of environment with local CO & SFR data
• Rapid build-up of the stellar content in the protocluster core SPT2349$-$56 at $z=4.3$
• ALMA reveals large overdensity and strong clustering of galaxies in quasar environments at $z\sim 4$
• Molecular gas in CLASH brightest cluster galaxies at $z\sim 0.2-0.9$
• MAMMOTH: Confirmation of Two Massive Galaxy Overdensities at $z=2.24$ with H$\alpha$ Emitters
• High-resolution ALMA study of CO (2-1) line and dust continuum emissions in cluster galaxies at z = 1.46
• Quenching by gas compression and consumption: A case study of a massive radio galaxy at z = 2.57
• The GOGREEN Survey: Constraining the Satellite Quenching Timescale in Massive Clusters at $\mathbf{z}\gtrsim 1$
• Resolving Disks & Mergers in $z\sim 2$ Heavily Reddened Quasars and their Companion Galaxies with ALMA
• Significant Molecular Gas Deficiencies in Star-forming Cluster Galaxies at $z\sim 1.4$
• The HST See Change Program: I. Survey Design, Pipeline, and Supernova Discoveries
• The XXL Survey: XXXVII. The role of the environment in shaping the stellar population properties of galaxies at 0.1<z<0.5
• The H$\alpha$ star formation main sequence in cluster and field galaxies at $z\sim 1.6$
• The LEGA-C of nature and nurture in stellar populations of galaxies at z~0.6-1.0: D4000 and H-delta reveal different assembly histories for quiescent galaxies in different environments
• Molecular gas properties of Planck-selected protocluster candidates at z~1.3-3
• ENISALA: II. Distinct Star Formation and Active Galactic Nucleus Activity in Merging and Relaxed Galaxy Clusters
• Measuring the total infrared light from galaxy clusters at z=0.5-1.6: connecting stellar populations to dusty star formation
• A large-scale kinematic study of molecular gas in high-z cluster galaxies: Evidence for high levels of kinematic asymmetry
• The Evolution of AGN Activity in Brightest Cluster Galaxies
• Star forming and gas rich brightest cluster galaxies at $z\sim 0.4$ in the Kilo-Degree Survey
• A CO Survey of SpARCS Star-Forming Brightest Cluster Galaxies: Evidence for Uniformity in BCG Molecular Gas Processing Across Cosmic Time
• SEEDisCS I. Molecular gas in galaxy clusters and their large scale structure: the case of CL1411.1$-$1148 at $z\sim 0.5$
• Massive molecular gas reservoir around the central AGN in the CARLA J1103+3449 cluster at z=1.44
• Accelerated structural evolution of galaxies in a starbursting cluster at z=2.51
• See Change: VLT spectroscopy of a sample of high-redshift Type Ia supernova host galaxies
• Faint polarised sources in the Lockman Hole field at 1.4 GHz
• The evolution of galaxy scaling relations in clusters at 0.5<z<1.5
• SEEDisCS II. Molecular gas in galaxy clusters and their large scale structure: low gas fraction galaxies, the case of CL1301.7$-$1139
• The relationship between cluster environment and molecular gas content of star-forming galaxies in the EAGLE simulation
• Molecular gas in a gravitationally lensed galaxy group at $z=2.9$
• An ALMA spectroscopic survey of the Planck high-redshift object PLCK G073.4-57.5 confirms two protoclusters
• PASSAGES: The Discovery of a Strongly Lensed Protocluster Core Candidate at Cosmic Noon
• ZFIRE -- The Gas Inflow Inequality for Satellite Galaxies in Cluster and Field Halos at z = 2
• ALMA measures molecular gas reservoirs comparable to field galaxies in a low-mass galaxy cluster at z=1.3
• The Photometric Analysis of the Environment Around Two Dusty Star-Forming Galaxies at $z\sim 2$
• Noema formIng Cluster survEy (NICE): A Census of Star Formation and Cold Gas Properties in Massive protoclusters at 1.5<z<4