Abstract
We report a detailed CO(1 0) survey of a galaxy protocluster field at z = 2:16, based on 475 h of observations with the Australia Telescope Compact Array. We constructed a large mosaic of 13 individual pointings, covering an area of 21 arcmin2 and similar to 6500 km s 1 range in velocity. We obtained a robust sample of 46 CO(1 0) detections spanning z = 2:09 2:22, constituting the largest sample of molecular gas measurements in protoclusters to date. The CO emitters show an overdensity at z = 2:12 2:21, suggesting a galaxy super-protocluster or a protocluster connected to large-scale filaments of similar to 120 cMpc in size. We find that 90% of CO emitters have distances >0:05 40 to the center galaxy, indicating that small area surveys would miss the majority of gas reservoirs in similar structures. Half of the CO emitters have velocities larger than escape velocities, which appears gravitationally unbound to the cluster core. These unbound sources are barely found within the R200 radius around the center, which is consistent with a picture in which the cluster core is collapsed while outer regions are still in formation. Compared to other protoclusters, this structure contains a relatively higher number of CO emitters with relatively narrow line widths and high luminosities, indicating galaxy mergers. We used these CO emitters to place the first constraint on the CO luminosity function and molecular gas density in an overdense environment. The amplitude of the CO luminosity function is 1.6 similar to 0.5 orders of magnitude higher than that observed for field galaxy samples at z similar to 2, and one order of magnitude higher than predictions for galaxy protoclusters from semi-analytical SHARK models. We derive a high molecular gas density of 0:6 1:3 similar to 109 M fi cMpc 3 for this structure, which is consistent with predictions for cold gas density of massive structures from hydro-dynamical DIANOGA simulations.
| Originalsprog | Engelsk |
|---|---|
| Artikelnummer | A11 |
| Tidsskrift | Astronomy & Astrophysics |
| Vol/bind | 652 |
| Antal sider | 23 |
| ISSN | 0004-6361 |
| DOI | |
| Status | Udgivet - 4 aug. 2021 |
Finansiering
The Australia Telescope Compact Array is part of the Australia Telescope National Facility which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Gomeroi people as the traditional owners of the Observatory site. This work is making use of observations made with ESO Telescopes at Paranal under programme 088.A-0754(B), 091.A-0106(A) and 094.A-0104(A). This research is based on observations made with the NASA/ESA Hubble Space Telescope obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program 10327. The authors thank Ian Smail, Stefano Borgani and Elena Rasia for helpful discussions in the preparation of this manuscript. The authors acknowledge Barbel Koribalski for help on ATCA observations and introduction of SoFiA. The authors thank Laura Lenki and Alberto D. Bolatto for helpful discussions on CO luminosity function. SJ, HD, and JMR acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities (MICIU) under grant AYA2017-84061-P, co-financed by FEDER (European Regional Development Funds) and the Agencia Estatal de Investigacion del Ministerio de Ciencia e Innovacion (AEI-MCINN) under grant (La evolucion de los cumulos de galaxias desde el amanecer hasta el mediodia cosmico) with reference (PID2019-105776GB-I00/DOI:10.13039/501100011033). HD acknowledges financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) under the 2014 Ramon y Cajal program MINECO RYC-2014-15686. BE acknowledges official funding from the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. CL is funded by the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. LB acknowledges ExaNeSt and Euro Exa projects, funded by the European Union Horizon 2020 research and innovation program under grant agreement No. 671553 and No. 754337, the agreement ASI-INAF n.2017-14-H.0; DIANOGA simulations have been carried out using MENDIETA Cluster from CCAD-UNC, which is part of SNCAD-MinCyT (Argentina); MARCONI at CINECA (Italy), with CPU time assigned through grants ISCRA B, and through INAF-CINECA and University of Trieste - CINECA agreements; at the Tianhe-2 platform of the Guangzhou Supercomputer Center by the support from the National Key Program for Science and Technology Research and Development (2017YFB0203300). The post-processing has been performed using the PICO HPC cluster at CINECA through an expression of interest. JBC thanks the National Science Foundation for support through grants AST-1714528 and AST-1814034, and additionally the University of Texas at Austin College of Natural Sciences. CMC thanks the National Science Foundation for support through grants AST-1814034 and AST-2009577, the University of Texas at Austin College of Natural Sciences, and the Research Corporation for Science Advancement from a 2019 Cottrell Scholar Award sponsored by IF/THEN, an initiative of Lyda Hill Philanthropies.
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