Darren Croton

Swinburne University of Technology

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Anton M. Koekemoer

Space Telescope Science Institute

David C. Koo

University of California, Santa Cruz

Jennifer M. Lotz

NSF’s NOIRLab

Jeffrey A. Newman

University of Pittsburgh

Rachel S. Somerville

Rutgers, The State University of New Jersey

Henry C. Ferguson

Space Telescope Science Institute

Norman A. Grogin

Space Telescope Science Institute

Dale D. Kocevski

Colby College

Jeyhan S. Kartaltepe

Rochester Institute of Technology

Eric F. Bell

University of Michigan–Ann Arbor

Cooperative Institutions

Centre National de la Recherche Scientifique

170

Max Planck Society

170

Max Planck Institute for Astronomy

124

ARC Centre of Excellence for All-sky Astrophysics

124

Space Telescope Science Institute

118

California Institute of Technology

104

Center for Astrophysics Harvard & Smithsonian

Australian National University

University of Sydney

ASTRO-3D

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WiggleZ Dark Energy Survey Baryon Acoustic Oscillation Random Catalogues

Zenodo (CERN European Organization for Nuclear Research) (2012)

Chris Blake Eyal Kazin Florian Buetler T. M. Davis David Parkinson

Data products associated with the WiggleZ Dark Energy survey measurement of the Baryon Acoustic Oscillations (BAO), as described in Blake et al. arXiv:1108.2635 (2011, MNRAS, 418, 1707) Data is given for 6 WiggleZ regions (01, 03, 09, 11, 15, 22 hrs) in 3 different overlapping redshift slices (z=0.2-0.6, 0.4-0.8, 0.6-1.0), matching the datasets analyzed in the final WiggleZ baryon acoustic peak paper Blake et al. (2011, MNRAS, 418, 1707). For each sub-region the following files are given: Correlation function: xi_**hr*.dat - correlation function measurement and covariance matrix for each sub-region. Format of the file: 1st line: nbin, ngalaxy nbin lines: mean separation [Mpc/h], xi(s), sqrt[Cov(i,i)] nbin x nbin lines: i, j, Cov(i,j) The covariance matrix is from lognormal realizations, not jack-knife regions. Combined correlation function: xi_combined*.dat - correlation function measurement for each redshift range combining the measurements in each sub-region, in the same format as above. Integral constant: wigglez_ic.dat - integral constraint correction which should be added to the measured correlation function, format of the file is: Region [hr], zmin, zmax, integral constraint delta-xi We are considering adding another 90 random catalogues in the near future. For now the random catalogues used in the previous analysis are available below.

Baryon Acoustic Oscillations

Oscillation (cell signaling)

10.5281/zenodo.33470

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The formation history of elliptical galaxies

Monthly Notices of the Royal Astronomical Society (2006)

G. De Lucia Volker Springel S. D. M. White Darren Croton Guinevere Kauffmann

We take advantage of the largest high-resolution simulation of cosmic structure growth ever carried out — the Millennium Simulation of the concordance Λ cold dark matter (CDM) cosmogony — to study how the star formation histories, ages and metallicities of elliptical galaxies depend on environment and on stellar mass. We concentrate on a galaxy formation model which is tuned to fit the joint luminosity/colour/morphology distribution of low-redshift galaxies. Massive ellipticals in this model have higher metal abundances, older luminosity-weighted ages and shorter star formation time-scales, but lower assembly redshifts, than less massive systems. Within clusters the typical masses, ages and metal abundances of ellipticals are predicted to decrease, on average, with increasing distance from the cluster centre. We also quantify the effective number of progenitors of ellipticals as a function of present stellar mass, finding typical numbers below two for M* < 1011 M⊙, rising to approximately five for the most massive systems. These findings are consistent with recent observational results that suggest 'down-sizing' or 'antihierarchical' behaviour for the star formation history of the elliptical galaxy population, despite the fact that our model includes all the standard elements of hierarchical galaxy formation and is implemented on the standard, ΛCDM cosmogony.

10.1111/j.1365-2966.2005.09879.x

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Citations (868)

The Three Hundred project: a large catalogue of theoretically modelled galaxy clusters for cosmological and astrophysical applications

Monthly Notices of the Royal Astronomical Society (2018)

Weiguang Cui Alexander Knebe Gustavo Yepes F. R. Pearce Chris Power

We introduce the THE THREE HUNDRED project, an endeavour to model 324 large galaxy clusters with full-physics hydrodynamical re-simulations. Here we present the data set and study the differences to observations for fundamental galaxy cluster properties and scaling relations. We find that the modelled galaxy clusters are generally in reasonable agreement with observations with respect to baryonic fractions and gas scaling relations at redshift z = 0. However, there are still some (model-dependent) differences, such as central galaxies being too massive, and galaxy colours (g - r) being bluer (about 0.2 dex lower at the peak position) than in observations. The agreement in gas scaling relations down to 10^{13} h^{-1} M_{\odot} between the simulations indicates that particulars of the sub-grid modelling of the baryonic physics only has a weak influence on these relations. We also include - where appropriate - a comparison to three semi-analytical galaxy formation models as applied to the same underlying dark-matter-only simulation. All simulations and derived data products are publicly available.

10.1093/mnras/sty2111

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Citations (182)

Evolution in the Halo Masses of Isolated Galaxies betweenz∼ 1 andz∼ 0: From DEEP2 to SDSS

The Astrophysical Journal (2006)

Charlie Conroy Francisco Prada Jeffrey A. Newman Darren Croton Alison L. Coil

We measure the evolution in the virial mass-to-light ratio (M_{200}/L_B) and virial-to-stellar mass ratio (M_{200}/M_\ast) for isolated ~ L* galaxies between z~1 and z~0 by combining data from the DEEP2 Galaxy Redshift Survey and the Sloan Digital Sky Survey. Utilizing the motions of satellite galaxies around isolated galaxies, we measure line-of-sight velocity dispersions and derive dark matter halo virial masses for these host galaxies. At both epochs the velocity dispersion of satellites correlates with host galaxy stellar mass, σ\propto M_\ast^{0.4+/-0.1}, while the relation between satellite velocity dispersion and host galaxy B-band luminosity may grow somewhat shallower from σ\propto L_B^{0.6+/-0.1} at z~1 to σ\propto L_B^{0.4+/-0.1} at z~0. The evolution in M_200/M_\ast from z~1 to z~0 displays a bimodality insofar as host galaxies with stellar mass below M_\ast ~10^{11} M_Sun/h maintain a constant ratio (the intrinsic increase is constrained to a factor of 1.1+/-0.7) while host galaxies above M_\ast ~10^{11} M_Sun/h experience a factor of 4+/-3 increase in their virial-to-stellar mass ratio. This result can be easily understood if galaxies below this stellar mass scale continue to form stars while star formation in galaxies above this scale is quenched and the dark matter halos of galaxies both above and below this scale grow in accordance with LCDM cosmological simulations. Host galaxies that are red in U-B color have larger satellite dispersions and hence reside on average in more massive halos than blue galaxies at both z~1 and z~0. The redshift and host galaxy stellar mass dependence of M_200/M_\ast agrees qualitatively with the Millennium Run semi-analytic model of galaxy formation. (ABRIDGED)

10.1086/509632

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CANDELS OBSERVATIONS OF THE ENVIRONMENTAL DEPENDENCE OF THE COLOR-MASS-MORPHOLOGY RELATION ATz= 1.6

The Astrophysical Journal (2013)

Robert Bassett Casey Papovich Jennifer M. Lotz Eric F. Bell Steven L. Finkelstein

We study the environmental dependence of color, stellar mass, and morphology by comparing galaxies in a forming cluster to those in the field at z = 1.6 with Hubble Space Telescope near-infrared imaging in the CANDELS/UDS field. We quantify the morphology of the galaxies using the effective radius, reff, and Sérsic index, n. In both the cluster and field, approximately half of the bulge-dominated galaxies (n > 2) reside on the red sequence of the color–magnitude diagram, and most disk-dominated galaxies (n < 2) have colors expected for star-forming galaxies. There is weak evidence that cluster galaxies have redder rest-frame U − B colors and higher stellar masses compared to the field. Star-forming galaxies in both the cluster and field show no significant differences in their morphologies. In contrast, there is evidence that quiescent galaxies in the cluster have larger median effective radii and smaller Sérsic indices compared to the field with a significance of 2σ. These differences are most pronounced for galaxies at clustercentric distances 1 Mpc

Peculiar galaxy

Stellar mass

10.1088/0004-637x/770/1/58

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Citations (56)

Measures of galaxy environment - I. What is ‘environment’?

Monthly Notices of the Royal Astronomical Society (2011)

Stuart I. Muldrew Darren Croton Ramin Skibba F. R. Pearce Hong Bae Ann

The influence of a galaxy's environment on its evolution has been studied and compared extensively in the literature, although differing techniques are often used to define environment. Most methods fall into two broad groups: those that use nearest neighbours to probe the underlying density field and those that use fixed apertures. The differences between the two inhibit a clean comparison between analyses and leave open the possibility that, even with the same data, different properties are actually being measured. In this work we apply twenty published environment definitions to a common mock galaxy catalogue constrained to look like the local Universe. We find that nearest neighbour-based measures best probe the internal densities of high-mass haloes, while at low masses the inter-halo separation dominates and acts to smooth out local density variations. The resulting correlation also shows that nearest neighbour galaxy environment is largely independent of dark matter halo mass. Conversely, aperture-based methods that probe super-halo scales accurately identify high-density regions corresponding to high mass haloes. Both methods show how galaxies in dense environments tend to be redder, with the exception of the largest apertures, but these are the strongest at recovering the background dark matter environment. We also warn against using photometric redshifts to define environment in all but the densest regions. When considering environment there are two regimes: the 'local environment' internal to a halo best measured with nearest neighbour and 'large-scale environment' external to a halo best measured with apertures. This leads to the conclusion that there is no universal environment measure and the most suitable method depends on the scale being probed.

10.1111/j.1365-2966.2011.19922.x

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Citations (155)

Galaxy cluster mass reconstruction project – I. Methods and first results on galaxy-based techniques

Monthly Notices of the Royal Astronomical Society (2014)

Lyndsay Old R. Skibba F. R. Pearce Darren Croton Stuart I. Muldrew

This paper is the first in a series in which we perform an extensive comparison of various galaxy-based cluster mass estimation techniques that utilise the positions, velocities and colours of galaxies. Our primary aim is to test the performance of these cluster mass estimation techniques on a diverse set of models that will increase in complexity. We begin by providing participating methods with data from a simple model that delivers idealised clusters, enabling us to quantify the underlying scatter intrinsic to these mass estimation techniques. The mock catalogue is based on a Halo Occupation Distribution (HOD) model that assumes spherical Navarro, Frenk and White (NFW) haloes truncated at R_200, with no substructure nor colour segregation, and with isotropic, isothermal Maxwellian velocities. We find that, above 10^14 M_solar, recovered cluster masses are correlated with the true underlying cluster mass with an intrinsic scatter of typically a factor of two. Below 10^14 M_solar, the scatter rises as the number of member galaxies drops and rapidly approaches an order of magnitude. We find that richness-based methods deliver the lowest scatter, but it is not clear whether such accuracy may simply be the result of using an over-simplistic model to populate the galaxies in their haloes. Even when given the true cluster membership, large scatter is observed for the majority non-richness-based approaches, suggesting that mass reconstruction with a low number of dynamical tracers is inherently problematic.

Substructure

10.1093/mnras/stu545

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Citations (74)

Do You See What I See? Exploring the Consequences of Luminosity Limits in Black Hole–Galaxy Evolution Studies

The Astrophysical Journal (2017)

Mackenzie L. Jones Ryan C. Hickox Simon J. Mutch Darren Croton A. Ptak

In studies of the connection between active galactic nuclei (AGN) and their host galaxies there is widespread disagreement on some key aspects stemming largely from a lack of understanding of the nature of the full underlying AGN population. Recent attempts to probe this connection utilize both observations and simulations to correct for a missed population, but presently are limited by intrinsic biases and complicated models. We take a simple simulation for galaxy evolution and add a new prescription for AGN activity to connect galaxy growth to dark matter halo properties and AGN activity to star formation. We explicitly model selection effects to produce an "observed" AGN population for comparison with observations and empirically motivated models of the local universe. This allows us to bypass the difficulties inherent in many models which attempt to infer the AGN population by inverting selection effects. We investigate the impact of selecting AGN based on thresholds in luminosity or Eddington ratio on the "observed" AGN population. By limiting our model AGN sample in luminosity, we are able to recreate the observed local AGN luminosity function and specific star formation-stellar mass distribution, and show that using an Eddington ratio threshold introduces less bias into the sample by selecting the full range of growing black holes, despite the challenge of selecting low mass black holes. We find that selecting AGN using these various thresholds yield samples with different AGN host galaxy properties.

Black hole (networking)

Stellar mass

10.3847/1538-4357/aa7632

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Citations (8)

Major Mergers in CANDELS up to z=3: Calibrating the Close-Pair Method Using Semi-Analytic Models and Baryonic Mass Ratio Estimates

AAS (2018)

Kameswara Bharadwaj Mantha Daniel H. McIntosh Christopher J. Conselice J. Cook Darren Croton

Mass ratio

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Measures of galaxy environment – III. Difficulties in identifying protoclusters at z ∼ 2

Monthly Notices of the Royal Astronomical Society (2013)

Genevieve M. Shattow Darren Croton Ramin Skibba Stuart I. Muldrew F. R. Pearce

Galaxy environment is frequently discussed, but inconsistently defined. It is especially difficult to measure at high redshift where only photometric redshifts are available. With a focus on early forming protoclusters, we use a semi-analytical model of galaxy formation to show how the environment measurement around high-redshift galaxies is sensitive to both scale and metric, as well as to cluster viewing angle, evolutionary state and the availability of either spectroscopic or photometric data. We use two types of environment metrics (nearest-neighbour and fixed aperture) at a range of scales on simulated high-z clusters to see how ‘observed’ overdensities compare to ‘real’ overdensities. We also ‘observationally’ identify z = 2 protocluster candidates in our model and track the growth histories of their parent haloes through time, considering in particular their final state at z = 0. Although the measured environment of early forming clusters is critically dependent on all of the above effects (and in particular the viewing angle), we show that such clusters are very likely ( ≳ 90 per cent) to remain overdense at z = 0, although many will no longer be among the most massive. Object-to-object comparisons using different methodologies and different data, however, require much more caution.

10.1093/mnras/stt998

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Citations (24)