Discovery of an HI-rich Gas Reservoir in the Outskirts of SZ-effect Selected Clusters

Abstract

We report on the detection of three strong HI absorbers originating in the outskirts (i.e., impact parameter, ${\rho }_{\mathrm{cl}}\approx (1.6-4.7)r_{500}$) of three massive ($M_{500}\sim 3\times 10^{14}{M}_{\odot }$) clusters of galaxies at redshift $z_{\mathrm{cl}}\approx 0.46$, in the $HubbleSpaceTelescope$ Cosmic Origins Spectrograph ($HST$/COS) spectra of 3 background UV-bright quasars. These clusters were discovered by the 2500 deg${}^2$ South Pole Telescope Sunyaev$-$Zel'dovich (SZ) effect survey. All three COS spectra show partial Lyman limit absorber with $N(HI)>10^{16.5}\mathrm{c}{\mathrm{m}}^{-2}$ near the photometric redshifts ($|\Delta z/(1+z)|\approx 0.03$) of the clusters. The compound probability of random occurrence of all three absorbers is $<0.02$%, indicating that the absorbers are most likely related to the targeted clusters. We find that the outskirts of these SZ-selected clusters are remarkably rich in cool gas compared to existing observations of other clusters in the literature. The effective Doppler parameters of the Lyman series lines, obtained using single cloud curve-of-growth (COG) analysis, suggest a non-thermal/turbulent velocity of a few $\times 10\mathrm{km}{\mathrm{s}}^{-1}$ in the absorbing gas. We emphasize the need for uniform galaxy surveys around these fields and for more UV observations of QSO-cluster pairs in general in order to improve the statistics and gain further insights into the unexplored territory of the largest collapsed cosmic structures.

arXiv commentAccepted for publication in ApJ Letters (6 pages)

References in corpus (27)

• Tracing cosmic evolution with clusters of galaxies
• Galaxy Clusters Discovered via the Sunyaev-Zel'dovich Effect in the 2500-square-degree SPT-SZ survey
• The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-Redshift Circumgalactic Medium
• The Cosmic Origins Spectrograph
• Sample Variance Considerations for Cluster Surveys
• A Census of Baryons in Galaxy Clusters and Groups
• The COS-Halos Survey: Rationale, Design, and A Census of Circumgalactic Neutral Hydrogen
• Galaxy Cluster Baryon Fractions Revisited
• Probing the IGM/Galaxy Connection V: On the Origin of Lya and OVI Absorption at z<0.2
• Baryons at the Edge of the X-ray Brightest Galaxy Cluster
• The COS-Halos Survey: Metallicities in the Low-Redshift Circumgalactic Medium
• The Hydrangea simulations: galaxy formation in and around massive clusters
• An HST/COS Survey of the Low-Redshift IGM. I. Survey, Methodology, & Overall Results
• Metal-line absorption around $z\approx$2.4 star-forming galaxies in the Keck Baryonic Structure Survey
• The Cosmic Origins Spectrograph: On-Orbit Instrument Performance
• Mass Accretion and its Effects on the Self-Similarity of Gas Profiles in the Outskirts of Galaxy Clusters
• Azimuthally Resolved X-Ray Spectroscopy to the Edge of the Perseus Cluster
• Studying the Diversity of Type Ia Supernovae in the Ultraviolet: Comparing Models with Observations
• The Azimuthal Dependence of Outflows and Accretion Detected Using OVI Absorption
• Discovery of a Primitive Damped Lyman alpha Absorber Near an X-ray Bright Galaxy Group in the Virgo Cluster
• Broad HI Absorbers as Metallicity-Independent Tracers of the Warm-Hot Intergalactic Medium
• Warm-hot Gas in X-ray Bright Galaxy Clusters and the H I-deficient Circumgalactic Medium in Dense Environments
• Warm Gas in the Virgo Cluster: I. Distribution of Lya Absorbers
• Predicting Merger-Induced Gas Motions in Lambda-CDM Galaxy Clusters
• The UV-bright Quasar Survey (UVQS): DR1
• The Influence of Environment on the Circumgalactic Medium
• Lyman-alpha Absorbers and the Coma Cluster

Cited by in corpus (12)

• Simulating Groups and the IntraGroup Medium: The Surprisingly Complex and Rich Middle Ground Between Clusters and Galaxies
• Characterizing Circumgalactic Gas around Massive Ellipticals at z ~ 0.4 I. Initial Results
• Warm-hot Gas in X-ray Bright Galaxy Clusters and the H I-deficient Circumgalactic Medium in Dense Environments
• The Red Dead Redemption Survey of Circumgalactic Gas About Massive Galaxies. I. Mass and Metallicity of the Cool Phase
• Cool circumgalactic gas in galaxy clusters: connecting the DESI legacy imaging survey and SDSS DR16 MgII absorbers
• Ultraviolet Signatures of the Multiphase Intracluster and Circumgalactic Media in the RomulusC Simulation
• Discovery of a cool, metal-rich gas reservoir in the outskirts of z ~ 0.5 clusters
• COS Observations of the Cosmic Web: A Search for the Cooler Components of a Hot, X-ray Identified Filament
• Detection of Metal-Rich, Cool-Warm Gas in the Outskirts of Galaxy Clusters
• A partial Lyman limit system tracing intragroup gas at $z\approx 0.8$ towards HE1003+0149
• Pair Lines of Sight Observations of Multiphase Gas Bearing O VI in a Galaxy Environment
• Free-floating molecular clumps and gas mixing: hydrodynamic aftermaths of the intracluster$-$interstellar medium interaction