Searching for the shadows of giants: characterising protoclusters with line of sight Lyman-α absorption

Abstract

We use state of the art hydrodyamical simulations from the Sherwood, EAGLE and Illustris projects to examine the signature of $M_{\mathrm{z}=0}\simeq 10^{14}{M}_{\odot }$ protoclusters observed in Ly-$\alpha$ absorption at $z\simeq 2.4$. We find there is a weak correlation between the mass overdensity, ${\delta }_{\mathrm{m}}$, and the Ly-$\alpha$ effective optical depth relative to the mean, ${\delta }_{{\tau }_{\text{eff}}}$, averaged over $15h^{-1}\mathrm{cMpc}$ scales, although scatter in the ${\delta }_{\mathrm{m}}$--${\delta }_{{\tau }_{\text{eff}}}$ plane means it is not possible to uniquely identify large scale overdensities with strong Ly-$\alpha$ absorption. Although all protoclusters are associated with large scale mass overdensities, most sight lines through protoclusters in a $\sim 10^6$ $\mathrm{cMp}{\mathrm{c}}^3$ volume probe the low column density Ly-$\alpha$ forest. A small subset of sight lines that pass through protoclusters exhibit coherent, strong Ly-$\alpha$ absorption on $15h^{-1}\mathrm{cMpc}$ scales, although these correspond to a wide range in mass overdensity. Assuming perfect removal of contamination by Ly-$\alpha$ absorbers with damping wings, more than half of the remaining sight lines with ${\delta }_{{\tau }_{\mathrm{eff}}}>3.5$ trace protoclusters. It is furthermore possible to identify a model dependent ${\delta }_{{\tau }_{\mathrm{eff}}}$ threshold that selects only protoclusters. However, such regions are rare: excluding absorption caused by damped systems, less than 0.1 per cent of sight lines that pass through a protocluster have ${\delta }_{{\tau }_{\mathrm{eff}}}>3.5$, meaning that any protocluster sample selected in this manner will also be highly incomplete. On the other hand, coherent regions of Ly-$\alpha$ absorption also provide a promising route for identifying and studying filamentary environments at high redshift.

arXiv comment18 pages, 18 figures, 3 tables; accepted for publication in MNRAS

References in corpus (82)

• Galactic Stellar and Substellar Initial Mass Function
• Planck 2013 results. XVI. Cosmological parameters
• The cosmological simulation code GADGET-2
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• Cosmic Star Formation History
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• Cosmological SPH simulations: A hybrid multi-phase model for star formation
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• The Baryon Oscillation Spectroscopic Survey of SDSS-III
• The Cosmic Evolution Survey (COSMOS) -- Overview
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• Radiative transfer in a clumpy universe: IV. New synthesis models of the cosmic UV/X-ray background
• SparsePak: A Formatted Fiber Field Unit for The WIYN Telescope Bench Spectrograph. I. Design, Construction, and Calibration
• A model for cosmological simulations of galaxy formation physics
• Formation of Galaxy Clusters
• Cosmological simulations of the growth of supermassive black holes and feedback from active galactic nuclei: method and tests
• A New Calculation of the Ionizing Background Spectrum and the Effects of HeII Reionization
• On the relation between the Schmidt and Kennicutt-Schmidt star formation laws and its implications for numerical simulations
• A New Method For Galaxy Cluster Detection I: The Algorithm
• Simulating galactic outflows with thermal supernova feedback
• The Illustris Simulation: Public Data Release
• On the evolution of the HI column density distribution in cosmological simulations
• Galaxies and Intergalactic Matter at Redshift z~3: Overview
• The EAGLE simulations of galaxy formation: public release of halo and galaxy catalogues
• P3M-SPH simulations of the Lyman-alpha Forest
• Two bright submillimeter galaxies in a z=4.05 proto-cluster in GOODS-North, and accurate radio-infrared photometric redshifts
• Ancient Light from Young Cosmic Cities: Physical and Observational Signatures of Galaxy Proto-Clusters
• Detection of Extended He II Reionization in the Temperature Evolution of the Intergalactic Medium
• Column density distribution and cosmological mass density of neutral gas: Sloan Digital Sky Survey-III Data Release 9
• On the (Non)Evolution of HI Disks over Cosmic Time
• The realm of the galaxy protoclusters
• A massive proto-cluster of galaxies at a redshift of z {\approx} 5.3
• Inferring the dark matter power spectrum from the Lyman-alpha forest in high-resolution QSO absorption spectra
• Galaxy Clusters around radio-loud AGN at 1.3 < z < 3.2 as seen by Spitzer
• The Lyman-alpha forest opacity and the metagalactic hydrogen ionization rate at z~2-4
• Protoclusters associated with z > 2 radio galaxies. I. Characteristics of high redshift protoclusters
• Ingredients for 21cm intensity mapping
• What are Protoclusters? -- Defining High Redshift Galaxy Clusters and Protoclusters
• The Lyman-$\alpha$ forest in optically-thin hydrodynamical simulations
• The mass of a halo
• Spectroscopic Identification of a Proto-Cluster at z=2.300: Environmental Dependence of Galaxy Properties at High Redshift
• A Refined Measurement of the Mean Transmitted Flux in the Ly-alpha Forest over 2 < z < 5 Using Composite Quasar Spectra
• Shaping the galaxy stellar mass function with supernova- and AGN-driven winds
• The Sherwood simulation suite: overview and data comparisons with the Lyman-alpha forest at redshifts 2 < z < 5
• The EAGLE simulations: atomic hydrogen associated with galaxies
• Discovery of an Enormous Ly$\alpha$ nebula in a massive galaxy overdensity at $z=2.3$
• Through Thick and Thin - HI Absorption in Cosmological Simulations
• Voigt Profile Fitting to Quasar Absorption Lines: An Analytic Approximation to the Voigt-Hjerting Function
• Damped Lyman-alpha absorbers as a probe of stellar feedback
• A Group of Galaxies at Redshift 2.38
• First Data Release of the COSMOS Lyman-Alpha Mapping And Tomography Observations: 3D Lyman-$\alpha$ Forest Tomography at 2.05 < z < 2.55
• MApping the Most Massive Overdensities (MAMMOTH) II -- Discovery of an Extremely Massive Overdensity BOSS1441 at $z=2.32$
• GOLDRUSH. III. A Systematic Search of Protoclusters at $z\sim 4$ Based on the $>100\mathrm{de}{\mathrm{g}}^2$ Area
• The VIMOS Ultra Deep Survey: Emerging from the Dark, a Massive Proto-Cluster at z~4.57
• Discovery of a rich proto-cluster at z=2.9 and associated diffuse cold gas in the VIMOS Ultra-Deep Survey (VUDS)
• Surveying Galaxy Proto-clusters in Emission: A Large-scale Structure at z=2.44 and the Outlook for HETDEX
• Resolving the high redshift Lyman-alpha forest in smoothed particle hydrodynamics simulations
• Discovery of a large number of candidate proto-clusters traced by ~15 Mpc-scale galaxy overdensities in COSMOS
• An Overdensity of Galaxies near the Most Distant Radio-Loud Quasar
• Shadow of a Colossus: A z=2.45 Galaxy Protocluster Detected in 3D Ly-a Forest Tomographic Mapping of the COSMOS Field
• The primordial environment of super massive black holes: large scale galaxy overdensities around $z\sim 6$ QSOs with LBT
• MApping the Most Massive Overdensities Through Hydrogen (MAMMOTH) I: Methodology
• Clustering around the radio-galaxy MRC0316-257 at z=3.14
• VIMOS Ultra-Deep Survey (VUDS): Witnessing the Assembly of a Massive Cluster at z~3.3
• A z=2.5 protocluster associated with the radio galaxy MRC 2104-242: star formation and differing mass functions in dense environments
• Galaxy protocluster candidates around z ~ 2.4 radio galaxies
• Observational Requirements for Lyman-alpha Forest Tomographic Mapping of Large-Scale Structure at z ~ 2
• Characterising and Identifying Galaxy Protoclusters
• Protocluster Discovery in Tomographic Ly$\alpha$ Forest Flux Maps
• The evolution of HI and CIV quasar absorption line systems at 1.9 < z < 3.2
• The Impact of Different Physical Processes on the Statistics of Lyman-limit and Damped Lyman-alpha Absorbers
• Discovery of a Proto-cluster Associated with a Ly-$\alpha$ Blob Pair at z=2.3
• LyMAS: Predicting Large-Scale Lyman-alpha Forest Statistics from the Dark Matter Density Field
• A Detection of $z$~2.3 Cosmic Voids from 3D Lyman-$\alpha$ Forest Tomography in the COSMOS Field
• WEAVE-QSO: A Massive Intergalactic Medium Survey for the William Herschel Telescope
• Overdensities of Extremely Red Objects in the Fields of High-Redshift Radio-Loud Quasars
• The Effect Of AGN Heating On The Low-Redshift Lyα Forest
• Discovery of an Overdensity of Lyman-alpha Emitters Around a $\mathrm{z}\sim 4$ QSO with the Large Binocular Telescope
• Cosmic Galaxy-IGM HI Relation at $z\sim 2-3$ Probed in the COSMOS/UltraVISTA $1.6$ deg${}^2$ Field
• A ~6 Mpc overdensity at z = 2.7 detected along a pair of quasar sight lines: filament or protocluster?

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• Probing the existence of a rich galaxy overdensity at z=5.2
• Spectroscopic Confirmation of two Extremely Massive Protoclusters BOSS1244 and BOSS1542 at $z=2.24$
• Probing Feedback via IGM tomography and Ly$\alpha$ forest with Subaru PFS, TMT/ELT, and JWST
• Statistical correlation between the distribution of Ly$\alpha$ emitters and IGM HI at $z\sim 2.2$ mapped by Subaru/Hyper Suprime-Cam
• Non-linearities in the Lyman-$\alpha$ forest and in its cross-correlation with dark matter halos
• TARDIS Paper II: Synergistic Density Reconstruction from Lyman-alpha Forest and Spectroscopic Galaxy Surveys with Applications to Protoclusters and the Cosmic Web
• 3D Distribution Map of HI Gas and Galaxies Around an Enormous Ly$\alpha$ Nebula and Three QSOs at $z=2.3$ Revealed by the HI Tomographic Mapping Technique
• The AGN fraction in high-redshift protocluster candidates selected by Planck and Herschel
• Searching for the shadows of giants II: the effect of local ionisation on the Lyman-$\alpha$ absorption signatures of protoclusters at redshift $z\sim 2.4$
• Connection Between Galaxies and HI in the Circumgalactic and Intergalactic Media: Variation According to Galaxy Stellar Mass and Star-formation Activity
• The Lyman-limit photon mean free path at the end of late reionisation in the Sherwood-Relics simulations
• LATIS: A Sample of IGM-selected Protoclusters and Protogroups at $z\sim 2.5$