Cold mode gas accretion on two galaxy groups at z ∼ 2
Abstract
We present Keck Cosmic Web Imager (KCWI) integral field spectroscopy (IFS) observations of rest-frame UV emission lines Lyα, CIVλλ 1548 Å, 1550Å, and HeII 1640 Å observed in the circumgalactic medium (CGM) of two z = 2 radio-loud quasar host galaxies. We detect extended emission on 80–90 kpc scale in Lyα in both systems with CIV and HeII emission also detected out to 30–50 kpc. All emission lines show kinematics with a blue and redshifted gradient pattern consistent with velocities seen in massive dark matter haloes and similar to kinematic patterns of inflowing gas seen in hydrodynamical simulations. Using the kinematics of both resolved Lyα emission and absorption, we can confirm that both kinematic structures are associated with accretion. Combining the KCWI data with molecular gas observations with Atacama Large Millimeter/submillimeter Array (ALMA) and high-spatial resolution of ionized gas with Keck OSIRIS, we find that both quasar host galaxies reside in proto-group environments at z = 2. We estimate 1–6 × 10¹⁰ M_⊙ of warm-ionized gas within 30–50 kpc from the quasar that is likely accreting on to the galaxy group. We estimate inflow rates of 60–200 M_⊙ yr⁻¹, within an order of magnitude of the outflow rates in these systems. In the 4C 09.17 system, we detect narrow gas streams associated with satellite galaxies, potentially reminiscent of ram-pressure stripping seen in local galaxy groups and clusters. We find that the quasar host galaxies reside in dynamically complex environments, with ongoing mergers, gas accretion, ISM stripping, and outflows likely playing an important role in shaping the assembly and evolution of massive galaxies at cosmic noon.
Additional Information
The authors wish to thanks Jim Lyke, Randy Campbell, and other SAs with their assistance at the telescope to acquire the Keck OSIRIS data sets. We would like to thank Erica Keller, Melissa Hoffman, and Loreto Barcos Munoz for assistance with ALMA data reduction and imaging at NRAO. This paper makes use of the following ALMA data: ADS/JAO.ALMA 2013.1.01359.S and ADS/JAO.ALMA 2017.1.01527.S. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. AV, NLZ, and YI acknowledge support from NASA ADAP grant 80NSSC21K1569. NLZ was supported at the IAS by the J. Robert Oppenheimer Visiting Professorship and the Bershadsky Fund. We want to thank the anonymous referee for their constructive comments that helped improve the manuscript. AV and NLZ would like to thank Wuji Wang and Dominika Wylezalek for excellent discussions about CGM science with resolved Lyα absorption in haloes of luminous quasars. DATA AVAILABILITY. The Keck OSIRIS data of this work are publicly available from the Keck Observatory Archive (https://www2.keck.hawaii.edu/koa/public/koa.php). Source information is provided with this paper. Other data underlying this article will be shared on a reasonable request to the corresponding author.Additional details
- Eprint ID
- 119030
- Resolver ID
- CaltechAUTHORS:20230203-893210800.38
- ALMA partnership
- W. M. Keck Foundation
- NASA/JPL/Caltech
- 80NSSC21K1569
- NASA
- Institute for Advanced Study
- Created
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2023-02-28Created from EPrint's datestamp field
- Updated
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2023-02-28Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)