Ultra-Red Galaxies Signpost Candidate Proto-Clusters at High Redshift

Abstract

We present images obtained with LABOCA on the APEX telescope of a sample of 22 galaxies selected via their red Herschel SPIRE 250-, 350- and $500\text{-}\mu \text{m}$ colors. We aim to see if these luminous, rare and distant galaxies are signposting dense regions in the early Universe. Our $870\text{-}\mu \text{m}$ survey covers an area of $\approx 0.8{\text{deg}}^2$ down to an average r.m.s. of $3.9{\text{mJy beam}}^{-1}$, with our five deepest maps going $\approx 2\times$ deeper still. We catalog 86 DSFGs around our 'signposts', detected above a significance of $3.5\sigma$. This implies a $100\pm 30\%$ over-density of $S_{870}>8.5\text{mJy}$ DSFGs, excluding our signposts, when comparing our number counts to those in 'blank fields'. Thus, we are $99.93\%$ confident that our signposts are pinpointing over-dense regions in the Universe, and $\approx 95\%$ confident that these regions are over-dense by a factor of at least $\ge 1.5\times$. Using template SEDs and SPIRE/LABOCA photometry we derive a median photometric redshift of $z=3.2\pm 0.2$ for our signposts, with an interquartile range of $z=2.8\text{-}3.6$. We constrain the DSFGs likely responsible for this over-density to within $|\Delta z|\le 0.65$ of their respective signposts. These 'associated' DSFGs are radially distributed within $1.6\pm 0.5\text{Mpc}$ of their signposts, have median SFRs of $\approx (1.0\pm 0.2)\times 10^3{M}_{\odot }{\text{yr}}^{-1}$ (for a Salpeter stellar IMF) and median gas reservoirs of $\sim 1.7\times 10^{11}{M}_{\odot }$. These candidate proto-clusters have average total SFRs of at least $\approx (2.3\pm 0.5)\times 10^3{M}_{\odot }{\text{yr}}^{-1}$ and space densities of $\sim 9\times 10^{-7}{\text{Mpc}}^{-3}$, consistent with the idea that their constituents may evolve to become massive ETGs in the centers of the rich galaxy clusters we see today.

24 pages, 13 figures, 5 tables, submitted for publication in ApJ

References in corpus (38)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
• A Dust-Obscured Massive Maximum-Starburst Galaxy at a Redshift of 6.34
• The Detection of a Population of Submillimeter-Bright, Strongly-Lensed Galaxies
• Mid-Infrared Spectral Diagnosis of Submillimeter Galaxies
• Intense Star Formation within Resolved Compact Regions in a Galaxy at z=2.3
• The SCUBA-2 Cosmology Legacy Survey: 850um maps, catalogues and number counts
• The SCUBA HAlf Degree Extragalactic Survey (SHADES) - III. Identification of radio and mid-infrared counterparts to submillimetre galaxies
• A massive proto-cluster of galaxies at a redshift of z {\approx} 5.3
• The Large APEX Bolometer Camera LABOCA
• An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: High resolution 870um source counts
• The SCUBA-2 Cosmology Legacy Survey: ALMA resolves the rest-frame far-infrared emission of sub-millimeter galaxies
• The Herschel-ATLAS Data Release 1 Paper I: Maps, Catalogues and Number Counts
• An excess of dusty starbursts related to the Spiderweb galaxy
• ALMA spectroscopic survey in the Hubble Ultra Deep Field: Continuum number counts, resolved 1.2-mm extragalactic background, and properties of the faintest dusty star forming galaxies
• The evolution of CNO isotopes: a new window on cosmic star-formation history and the stellar IMF in the age of ALMA
• The Spiderweb galaxy: a forming massive cluster galaxy at z~2
• The DEEP2 galaxy redshift survey: the evolution of the blue fraction in groups and the field
• Galaxy And Mass Assembly (GAMA): Stellar mass functions by Hubble type
• The Role of Environment in the Mass-Metallicity Relation
• The space density of luminous dusty star-forming galaxies at $z>4$: SCUBA-2 and LABOCA imaging of ultrared galaxies from $Herschel$-ATLAS
• ALMA Imaging of HCN, CS and dust in Arp 220 and NGC 6240
• Spatial correlation between submillimetre and Lyman-alpha galaxies in the SSA 22 protocluster
• A dusty star-forming galaxy at z=6 revealed by strong gravitational lensing
• LCDM predictions for galaxy protoclusters I: the relation between galaxies, protoclusters and quasars at z~6
• The Herschel-ATLAS Data Release 1 Paper II: Multi-wavelength counterparts to submillimetre sources
• Rise of the Titans: A Dusty, Hyper-Luminous "870 micron Riser" Galaxy at z~6
• The primordial environment of super massive black holes: large scale galaxy overdensities around $z\sim 6$ QSOs with LBT
• The most distant, luminous, dusty star-forming galaxies: redshifts from NOEMA and ALMA spectral scans
• Luminous Quasars Do Not Live in the Most Overdense Regions of Galaxies at z~4
• Assembly of the Red Sequence in Infrared-Selected Galaxy Clusters from the IRAC Shallow Cluster Survey
• Multi-frequency imaging of the galaxy cluster Abell 2163 using the Sunyaev-Zel'dovich Effect
• The end of star formation in Chamaeleon I ? A LABOCA census of starless and protostellar cores
• Chandra deep observation of XDCP J0044.0-2033, a massive galaxy cluster at z>1.5
• Galaxy Merger Candidates in High-Redshift Cluster Environments
• Submillimeter observations of the J2142-4423 Lya protocluster at z = 2.38
• BoA: a versatile software for bolometer data reduction
• Witnessing the birth of the red sequence: the physical scale and morphology of dust emission in hyper-luminous starbursts in the early Universe
• Imaging the environment of a z = 6.3 submillimeter galaxy with SCUBA-2

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