Deep observations of CO line emission from star-forming galaxies in a cluster candidate at z=1.5

Abstract

We report results from a deep Jansky Very Large Array (JVLA) search for CO 1-0 line emission from galaxies in a candidate galaxy cluster at z~1.55 in the COSMOS field. We target 4 galaxies with optical spectroscopic redshifts in the range z=1.47-1.59. Two of these 4 galaxies, ID51613 and ID51813, are nominally detected in CO line emission at the 3-4 sigma level. We find CO luminosities of 2.4x10^10 K km/s pc^2 and 1.3x10^10 K km/s pc^2, respectively. Taking advantage from the clustering and 2-GHz bandwidth of the JVLA, we perform a search for emission lines in the proximity of optical sources within the field of view of our observations. We limit our search to galaxies with K<23.5 (AB) and z_phot=1.2-1.8. We find 2 bright optical galaxies to be associated with significant emission line peaks (>4 sigma) in the data cube, which we identify with the CO line emission. To test the reliability of the line peaks found, we performed a parallel search for line peaks using a Bayesian inference method. Monte Carlo simulations show that such associations are statistically significant, with probabilities of chance association of 3.5% and 10.7% for ID 51207 and ID 51380, respectively. Modeling of their optical/IR SEDs indicates that the CO detected galaxies and candidates have stellar masses and SFRs in the range (0.3-1.1)x10^11 M_sun and 60-160 M_sun/yr, with SFEs comparable to that found in other star-forming galaxies at similar redshifts. By comparing the space density of CO emitters derived from our observations with the space density derived from previous CO detections at z~1.5, and with semi-analytic predictions for the CO luminosity function, we suggest that the latter tend to underestimate the number of CO galaxies detected at high-redshift. Finally, we argue about the benefits of future blind CO searches in clustered fields with upcoming submm/radio facilities.

Accepted for publication in MNRAS. Abstract has been slightly shortened compared to original pdf version

References in corpus (27)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• The Cosmic Evolution Survey (COSMOS) -- Overview
• Cold streams in early massive hot haloes as the main mode of galaxy formation
• The hierarchical formation of the brightest cluster galaxies
• COSMOS Photometric Redshifts with 30-bands for 2-deg2
• zCOSMOS: A Large VLT/VIMOS redshift survey covering 0 < z < 3 in the COSMOS field
• UV Luminosity Functions at z~4, 5, and 6 from the HUDF and other Deep HST ACS Fields: Evolution and Star Formation History
• Subaru Deep Survey V. A Census of Lyman Break Galaxies at z=4 and 5 in the Subaru Deep Fields: Photometric Properties
• Distant Radio Galaxies and their Environments
• Photometric redshift and classification for the XMM-COSMOS sources
• SHARC-2 350 Micron Observations of Distant Submillimeter Selected Galaxies
• The VLA-COSMOS Survey: II. Source Catalog of the Large Project
• Highly-excited CO emission in APM08279+5255 at z=3.9
• Vigorous star formation with low efficiency in massive disk galaxies at z=1.5
• A Massive Molecular Gas Reservoir in the z=5.3 Submillimeter Galaxy AzTEC-3
• CO(1-0) in z >/~ 4 Quasar Host Galaxies: No Evidence for Extended Molecular Gas Reservoirs
• Testing the Evolutionary Link Between Submillimetre Galaxies and Quasars: CO Observations of QSOs at z~2
• The VLA-COSMOS Survey: III. Further Catalog Analysis and the Radio Source Counts
• Molecular Gas in a Submillimeter Galaxy at z=4.5: Evidence for a Major Merger at 1 Billion Years after the Big Bang
• The Cosmic Decline in the H2/HI-Ratio in Galaxies
• HAWK-I imaging of the X-ray luminous galaxy cluster XMMU J2235.3-2557: The red sequence at z=1.39
• The dust un-biased cosmic star formation history from the 20 cm VLA-COSMOS survey
• The Cosmic Evolution Survey (COSMOS): a large-scale structure at z=0.73 and the relation of galaxy morphologies to local environment
• Interferometric detections of GOODS 850-5 at 1 mm and 1.4 GHz
• The WIRCAM Deep Infrared Cluster Survey I: Groups and Clusters at z > 1.1
• Properties of the molecular gas in a starbursting QSO at z=1.83 in the COSMOS field
• Molecular Gas in the z=1.2 Ultraluminous Merger GOODS J123634.53+621241.3

Cited by in corpus (49)

• Cool Gas in High Redshift Galaxies
• Dusty Star-Forming Galaxies at High Redshift
• Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z=4
• The ALMA Spectroscopic Survey in the HUDF: CO luminosity functions and the molecular gas content of galaxies through cosmic history
• A survey of the cold molecular gas in gravitationally lensed star-forming galaxies at z>2
• COLDz: Shape of the CO Luminosity Function at High Redshift and the Cold Gas History of the Universe
• ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Molecular gas reservoirs in high-redshift galaxies
• The ALMA Spectroscopic Survey in the HUDF: Multi-band constraints on line luminosity functions and the cosmic density of molecular gas
• An ALMA/NOEMA survey of the molecular gas properties of high-redshift star-forming galaxies
• The CO Luminosity Density at High-z (COLDz) Survey: A Sensitive, Large Area Blind Search for Low-J CO Emission from Cold Gas in the Early Universe with the Karl G. Jansky Very Large Array
• Molecular gas content in strongly-lensed z~1.5-3 star-forming galaxies with low IR luminosities
• ALMA Observations of Gas-Rich Galaxies in z~1.6 Galaxy Clusters: Evidence for Higher Gas Fractions in High-Density Environments
• Which galaxies dominate the neutral gas content of the Universe?
• Molecular gas reservoirs in cluster galaxies at z=1.46
• ALMA reveals starburst-like interstellar medium conditions in a compact star-forming galaxy at z ~ 2 using [CI] and CO
• The implications of the surprising existence of a large, massive CO disk in a distant protocluster
• CO(1-0) survey of high-z radio galaxies: alignment of molecular halo gas with distant radio sources
• Deep CO(1-0) Observations of z=1.62 Cluster Galaxies with Substantial Molecular Gas Reservoirs and Normal Star Formation Efficiencies
• Revealing environmental dependence of molecular gas content in a distant X-ray cluster at z=2.51
• Environmental impacts on molecular gas in protocluster galaxies at z~2
• Constraining the CO intensity mapping power spectrum at intermediate redshifts
• On the Gas Content, Star Formation Efficiency, and Environmental Quenching of Massive Galaxies in Proto-Clusters at z~2.0-2.5
• Evolutionary phases of gas-rich galaxies in a galaxy cluster at z=1.46
• Early Science with the Large Millimeter Telescope: COOL BUDHIES I - a pilot study of molecular and atomic gas at z~0.2
• CO luminosity function from Herschel-selected galaxies and the contribution of AGN
• Similar Scaling Relations for the Gas Content of Galaxies across Environments to z ~ 3.5
• Evidence for a gas-rich major merger in a proto-cluster at z=2.5
• The ALMA Frontier Fields Survey III: 1.1 mm Emission Line Identifications in Abell 2744, MACSJ0416.1-2403, MACSJ1149.5+2223, Abell 370, and Abell S1063
• Passive galaxies as tracers of cluster environments at z~2
• Molecular gas in CLASH brightest cluster galaxies at $z\sim 0.2-0.9$
• Using ALMA to resolve the nature of the early star-forming large-scale structure PLCK G073.4-57.5
• The AT-LESS CO(1-0) survey of submillimetre galaxies in the Extended Chandra Deep Field South: First results on cold molecular gas in galaxies at z ~ 2
• Molecular gas in two companion cluster galaxies at z=1.2
• Molecular gas in radio galaxies in dense Mpc-scale environments at $z=0.4-2.6$
• Lurking systematics in predicting galaxy cold gas masses using dust luminosities and star formation rates
• Molecular gas properties of Planck-selected protocluster candidates at z~1.3-3
• A Radio-to-millimeter Census of Star-forming Galaxies in Protocluster 4C~23.56 at z = 2.5 : Global and local gas kinematics
• Deciphering the activity and quiescence of high-redshift cluster environments: ALMA observations of ClJ1449+0856 at z=2
• Molecular gas in distant brightest cluster galaxies
• Star forming and gas rich brightest cluster galaxies at $z\sim 0.4$ in the Kilo-Degree Survey
• COLDz: Karl G. Jansky Very Large Array discovery of a gas-rich galaxy in COSMOS
• Foreground Removal of CO Intensity Mapping Using Deep Learning
• VLA detects CO(1-0) emission in the z=3.65 quasar SDSS J160705+533558
• A Bayesian blind survey for cold molecular gas in the Universe
• An ALMA spectroscopic survey of the Planck high-redshift object PLCK G073.4-57.5 confirms two protoclusters
• Vz-GAL: Probing Cold Molecular Gas in Dusty Star-forming Galaxies at z=1-6
• ALMA detects molecular gas in the halo of the powerful radio galaxy TXS 0828+193
• ALMA measures molecular gas reservoirs comparable to field galaxies in a low-mass galaxy cluster at z=1.3
• The interstellar medium content of galaxies in the ALMA era