Two 100 Mpc-scale structures in the 3-D distribution of radio galaxies and their implications

Abstract

We present unequivocal evidence for a huge (~80 x 100 x 100 Mpc^3) super-structure at redshift z=0.27 in the 3-D distribution of radio galaxies from the TONS08 sample, confirming tentative evidence for such a structure from the 7C redshift survey (7CRS). A second, newly discovered super-structure is also less securely found at redshift 0.35 (of dimensions ~100 x 100 x 100 Mpc^3). We present full observational details on the TONS08 sample which was constructed to probe structures in the redshift range 0 < z < 0.5 by matching NVSS sources with objects in APM catalogues to obtain a sample of optically bright (E ~ R < 19.83), radio faint (1.4-GHz flux density S_1.4 > 3 mJy) radio galaxies in the same 25 deg^2 area as part-II of the 7CRS. Out of the total sample size of 84 radio galaxies, at least 25 are associated with the two ~100 Mpc-scale super-structures. We use quasi-linear structure formation theory to estimate the number of such structures expected in the TONS08 volume if the canonical value for radio galaxy bias is assumed. Under this assumption, the structures represent ~ 4-5 sigma peaks in the primordial density field and their expected number is low (~10^-2 - 10^-4). Fortunately, there are several plausible explanations (many of which are testable) for these low probabilities in the form of potential mechanisms for boosting the bias on large scales. These include: the association of radio galaxies with highly biased rich clusters in super-structures, enhanced triggering by group/group mergers, and enhanced triggering and/or redshift space distortion in collapsing systems as the growth of super-structures moves into the non-linear regime (abridged).

arXiv commentAccepted for publication in MNRAS. 26 pages,16 figures. spectra can be found in: http://www-astro.physics.ox.ac.uk/~brand/08_paper.ps.gz

References in corpus (32)

• The 2dF Galaxy Redshift Survey: Spectra and redshifts
• Baryonic Features in the Matter Transfer Function
• The 2dF Galaxy Redshift Survey: The power spectrum and the matter content of the universe
• Reconstructing the linear power spectrum of cosmological mass fluctuations
• The 2dF Galaxy Redshift Survey: The bias of galaxies and the density of the Universe
• A Large Structure of Galaxies At Redshift z~3 and its Cosmological Implications
• Evolution of structure in cold dark matter universes
• The 2dF Galaxy Redshift Survey: The b_J-band galaxy luminosity function and survey selection function
• The 2dF Galaxy Redshift Survey: Spectral Types and Luminosity Functions
• The radio luminosity function from the low-frequency 3CRR, 6CE & 7CRS complete samples
• Radio sources in the 2dF Galaxy Redshift Survey - II. Local radio luminosity functions for AGN and star-forming galaxies at 1.4 GHz
• The 2dF Galaxy Redshift Survey: The amplitudes of fluctuations in the 2dFGRS and the CMB, and implications for galaxy biasing
• The Cosmic Microwave Background Anisotropy Power Spectrum measured by Archeops
• The Supercluster-Void Network I. The Supercluster Catalogue and Large-Scale Distribution
• The Nonlinear Evolution of Rare Events
• Cluster abundance normalization from observed mass-temperature relation
• Cosmic Shear and Power Spectrum Normalization with the Hubble Space Telescope
• Measurement of the angular correlation function of radio galaxies from the NRAO VLA Sky Survey
• The 2dF QSO Redshift Survey - II. Structure and evolution at high redshift
• Optical Counterparts for 70,000 Radio Sources: APM Identifications for the FIRST Radio Survey
• The 2dF Galaxy Redshift Survey: The population of nearby radio galaxies at the 1 mJy level
• Optical spectroscopy of radio galaxies in the 7C Redshift Survey
• Supercluster Properties as a Cosmological Probe
• The Power Spectrum of Rich Clusters on Near Gigaparsec Scales
• Discovery of Extreme Examples of Superclustering in Aquarius
• Sub-degree Scale Microwave Anisotropies from Cosmic Defects
• The radio galaxy 3C 356 and clues to the trigger mechanisms for powerful radio sources
• Abell 3560, a galaxy cluster at the edge of a major merging event
• Dynamical state of superclusters of galaxies: do superclusters expand or have they started to collapse?
• Large Scale Structure at z=1.2 Outlined by MgII Absorbers
• Radio Galaxy Clustering at z~0.3
• Galaxy and Cluster Biasing from Local Group Dynamics

Cited by in corpus (23)

• A structure in the early universe at z ~ 1.3 that exceeds the homogeneity scale of the R-W concordance cosmology
• Do submillimeter galaxies really trace the most massive dark matter halos? Discovery of a high-z cluster in a highly active phase of evolution
• The environmental dependence of radio-loud AGN activity and star formation in the 2dFGRS
• Radio Observations of the 13hr XMM/ROSAT Deep X-ray Survey Area
• Implications for unified schemes from the quasar fraction and emission-line luminosities in radio-selected samples
• The accretion history of the Universe with the SKA
• The angular power spectrum of NVSS radio galaxies
• On the X-ray emission of z~2 radio galaxies: IC scattering of the CMB & no evidence for fully-formed potential wells
• The Pisces-Cetus Supercluster: a remarkable filament of galaxies in the 2dF Galaxy Redshift Survey and Sloan Digital Sky surveys
• Two close Large Quasar Groups of size ~ 350 Mpc at z ~ 1.2
• LRS2: the new facility low resolution integral field spectrograph for the Hobby-Eberly Telescope
• Spectroscopic follow-up of a cluster candidate at z = 1.45
• FIRST winged radio galaxies with X and Z symmetry
• Suppressed radio emission in supercluster galaxies: enhanced ram pressure in merging clusters?
• The 3-D clustering of radio galaxies in the TONS survey
• Morphology of Mock SDSS Catalogues
• 200 Mpc Sized Structure in the 2dF QSO Redshift Survey
• Detection of 20-30 Mpc-scale Galaxy Structures Embedded in 100 Mpc-scale Structures of Quasars and MgII Absorbers at z~0.8 and z~1.2
• Unbiased Studies of Diffuse Extragalactic Radio Sources
• Searching for high-redshift centimeter-wave continuum, line and maser emission using the Square Kilometer Array
• Design and construction progress of LRS2-B: a new low resolution integral field spectrograph for the Hobby-Eberly Telescope
• Observing Magnetic Fields on Large Scales
• Adaptive Optics Imaging Survey of Luminous Infrared Galaxies