Identification of the progenitors of rich clusters and member galaxies in rapid formation at z>2

Abstract

We present the results of near-infrared spectroscopy of H$\alpha$ emitters (HAEs) associated with two protoclusters around radio galaxies (PKS1138-262 at $z$=2.2 and USS1558-003 at $z$=2.5) with Multi-Object Infrared Camera and Spectrograph (MOIRCS) on the Subaru telescope. Among the HAE candidates constructed from our narrow-band imaging, we have confirmed membership of 27 and 36 HAEs for the respective protoclusters, with a success rate of 70 per cent of our observed targets. The large number of spectroscopically confirmed members per cluster has enabled us for the first time to reveal the detailed kinematical structures of the protoclusters at $z$$>$2. The clusters show prominent substructures such as clumps, filaments and velocity gradients, suggesting that they are still in the midst of rapid construction to grow to rich clusters at later times. We also estimate dynamical masses of the clusters and substructures assuming their local virialization. The inferred masses ($\sim$10${}^{14}$M${}_{\odot }$) of the protocluster cores are consistent with being typical progenitors of the present-day most massive class of galaxy clusters ($\sim$10${}^{15}$M${}_{\odot }$) if we take into account the typical mass growth history of clusters. We then calculated the integrated star formation rates of the protocluster cores normalized by the dynamical masses, and compare these with lower redshift descendants. We see a marked increase of star-forming activities in the cluster cores, by almost three orders of magnitude, as we go back in time to 11 billion years ago; this scales as (1$+$$z$)${}^6$.

6 pages, 3 figures, 2 tables. Accepted for publication in the MNRAS Letter

References in corpus (2)

• The First Appearance of the Red Sequence of Galaxies in Proto-Clusters at 2<~z<~3
• Proto-Clusters with Evolved Populations around Radio Galaxies at z~2.5

Cited by in corpus (48)

• An excess of dusty starbursts related to the Spiderweb galaxy
• Why z > 1 radio-loud galaxies are commonly located in proto-clusters
• Stellar mass function of cluster galaxies at z $\sim$ 1.5: evidence for reduced quenching efficiency at high redshift
• Evidence for strong evolution in galaxy environmental quenching efficiency between z = 1.6 and z = 0.9
• MAHALO Deep Cluster Survey I. Accelerated and enhanced galaxy formation in the densest regions of a protocluster at z=2.5
• KECK/MOSFIRE spectroscopic confirmation of a Virgo-like cluster ancestor at z=2.095
• An early phase of environmental effects on galaxy properties unveiled by near-infrared spectroscopy of protocluster galaxies at z>2
• MC${}^2$: Boosted AGN and star-formation activity in CIZA J2242.8+5301, a massive post-merger cluster at z=0.19
• A proto-cluster at z=2.45
• Characterising and Identifying Galaxy Protoclusters
• Forming intracluster gas in a galaxy protocluster at a redshift of 2.16
• Environmental impacts on molecular gas in protocluster galaxies at z~2
• The Young and the Wild: What happens to Protoclusters forming at z = 4?
• The 700 ks Chandra Spiderweb Field I: evidence for widespread nuclear activity in the Protocluster
• COALAS: I. ATCA CO(1-0) survey and luminosity function in the Spiderweb protocluster at z=2.16
• The environmental impacts on the star formation main sequence: an H-alpha study of the newly discovered rich cluster at z=1.52
• Spectroscopic observations of PHz G237.01+42.50: A galaxy protocluster at z=2.16 in the Cosmos field
• Direct evidence for Ly$\alpha$ depletion in the protocluster core
• Signs of environmental effects on star-forming galaxies in the Spiderweb protocluster at z=2.16
• Enhanced Star Formation of Less Massive Galaxies in a Proto-Cluster at z=2.5
• The 700 ks Chandra Spiderweb Field II: Evidence for inverse-Compton and thermal diffuse emission in the Spiderweb galaxy
• Probing the existence of a rich galaxy overdensity at z=5.2
• Evidence for a gas-rich major merger in a proto-cluster at z=2.5
• Evaluating Lya Emission as a Tracer of the Largest Cosmic Structure at z~2.47
• The candidate cluster and protocluster catalog (CCPC) II: Spectroscopically identified structures spanning 2 < z < 6.6
• Implications of the Environments of Radio-detected AGN in a Complex Protostructure at z$\sim$3.3
• Bayesian model selection on Scalar $\epsilon$-Field Dark Energy
• Spectroscopic Confirmation of two Extremely Massive Protoclusters BOSS1244 and BOSS1542 at $z=2.24$
• Statistical correlation between the distribution of Ly$\alpha$ emitters and IGM HI at $z\sim 2.2$ mapped by Subaru/Hyper Suprime-Cam
• High-resolution ALMA study of CO (2-1) line and dust continuum emissions in cluster galaxies at z = 1.46
• RXJ0848.6+4453: The Evolution of Galaxy Sizes and Stellar Populations in a z=1.27 Cluster
• The submillimetre view of massive clusters at z~0.8-1.6
• Similarities and uniqueness of Ly$\alpha$ emitters among star-forming galaxies at z=2.5
• NOEMA formIng Cluster survEy (NICE): Characterizing eight massive galaxy groups at $1.5<z<4$ in the COSMOS field
• Revealing Dust Obscured Star Formation in CLJ1449+0856, a Cluster at z=2
• Revealing the quiescent galaxy population in the Spiderweb protocluster at z=2.16 with deep HST/WFC3 slitless spectroscopy
• ASW${}^2$DF: Census of the obscured star formation in a galaxy cluster in formation at $z=2.2$
• A systematic search for galaxy protocluster cores at the transition epoch of their star formation activity
• Early Quenching of Massive Protocluster Galaxies Around z=2.2 Radio Galaxies
• COALAS III: The ATCA CO(1-0) look at the growth and death of H$\alpha$ emitters in the Spiderweb protocluster at z=2.16
• JWST/NIRCam Narrowband Survey of Pa$\beta$ Emitters in the Spiderweb Protocluster at z=2.16
• Probing the Mpc-scale environment of hyperluminous infrared galaxies at 2<z<4
• Galaxy populations of ProtoClusters in cosmological hydrodynamical simulations
• Are Lyα emitters segregated in protoclusters regions?
• Cosmic Vine: High abundance of massive galaxies and dark matter halos in a forming cluster at z=3.44
• JWST reveals extended stellar disks for ALMA-bright dusty star-forming galaxies in the Spiderweb protocluster
• GLACE survey: OSIRIS/GTC tuneable imaging of the galaxy cluster ZwCl 0024.0+1652 II. The mass--metallicity relationship and the effect of the environment
• Spider-Webb: enhanced star formation in low-mass galaxies within the Spiderweb protocluster revealed by JWST Pa$\beta$ narrow-band imaging