# Last entries in the CiteULike library

For the full list: http://www.citeulike.org/group/13962/

EarlierStellar mass dependence of the 21-cm signal around the first star and its impact on the global signal(21 May 2018)The 21-cm signal in the vicinity of the first stars is expected to reflect properties of the first stars. In this study we pay special attention to tracing the time evolution of the ionizing photons' escape fraction, which affects the distribution of neutral hydrogen, by performing radiation hydrodynamics [...]Tue, May 22, 2018Source: CiteULike Group Cosmo LUTHTree-less 3d Friends-of-Friends using Spatial Hashing(13 May 2018)I describe a fast algorithm for the identification of connected sets of points where the point-wise connections are determined by a fixed spatial distance - a task commonly referred to in the cosmological simulation community as Friends-of-Friends (FOF) group finding. This technique sorts particles into fine cells sufficiently [...]Thu, May 17, 2018Source: CiteULike Group Cosmo LUTHSystematics in virial mass estimators for pressure-supported systems(1 May 2018)Mass estimators are a key tool to infer the distribution of dark matter in pressure-supported systems like dwarf spheroidal galaxies (dSphs). We construct an estimator for enclosed masses based on the virial theorem which is insensitive to anisotropy in the velocity dispersion and tailored to yield masses with [...]Thu, May 03, 2018Source: CiteULike Group Cosmo LUTHX-ray properties of AGN in Brightest Cluster Galaxies I: a systematic study of the Chandra archive in the $0.2<z<0.3$ and $0.55<z<0.75$ redshift range(23 Apr 2018)We present a search for nuclear X-ray emission in the Brightest Cluster Galaxies (BCGs) of a sample of groups and clusters of galaxies extracted from the Chandra archive. The exquisite angular resolution of Chandra allows us to obtain robust photometry at the position of the BCG, and to [...]Wed, Apr 25, 2018Source: CiteULike Group Cosmo LUTHAnalyzing astronomical data with Apache Spark(20 Apr 2018)We investigate the performances of Apache Spark, a cluster computing framework, for analyzing data from future LSST-like galaxy surveys. Apache Spark attempts to address big data problems have hitherto proved successful in the industry, but its main use is often limited to naively structured data. We show how [...]Mon, Apr 23, 2018Source: CiteULike Group Cosmo LUTHLegacy of star formation in the pre-reionization universe(19 Apr 2018)We utilize the hydrodynamic and N-body code GIZMO, coupled with newly developed sub-grid Legacy models for Population~III (Pop~III) and Population~II (Pop~II), specifically designed for meso-scale cosmological volume simulations, to study the legacy of star formation in the pre-reionization Universe. We find that the Pop~II star formation rate density [...]Mon, Apr 23, 2018Source: CiteULike Group Cosmo LUTHSetting the stage for cosmic chronometers I. Minimizing frosting with an optimized selection of cosmic chronometers(16 Apr 2018)The expansion history of the Universe can be constrained in a cosmology-independent way by measuring the differential age evolution of cosmic chronometers. This yields a measurement of the Hubble parameter as a function of redshift. The most reliable cosmic chronometers known so far are extremely massive and passively [...]Wed, Apr 18, 2018Source: CiteULike Group Cosmo LUTHCurrent velocity data on dwarf galaxy NGC1052-DF2 do not constrain it to lack dark matter(11 Apr 2018)It was recently proposed that the globular cluster system of the very low surface-brightness galaxy NGC1052-DF2 is dynamically very cold, leading to the conclusion that this dwarf galaxy has little or no dark matter. Here, we show that a robust statistical measure of the velocity dispersion of the [...]Fri, Apr 13, 2018Source: CiteULike Group Cosmo LUTHMeasured and found wanting: reconciling mass-estimates of ultra-diffuse galaxies(11 Apr 2018)The virial masses of ultra-diffuse galaxies (UDGs) have been estimated using the kinematics and abundance of their globular cluster populations, leading to disparate results. Some studies conclude that UDGs reside in massive dark matter halos while others, controversially, argue for the existence of UDGs with no dark matter [...]Fri, Apr 13, 2018Source: CiteULike Group Cosmo LUTHStellar Velocity Dispersion: Linking Quiescent Galaxies to their Dark Matter Halos(12 Apr 2018)We analyze the Illustris-1 hydrodynamical cosmological simulation to explore the stellar velocity dispersion of quiescent galaxies as an observational probe of dark matter halo velocity dispersion and mass. Stellar velocity dispersion is proportional to dark matter halo velocity dispersion for both central and satellite galaxies. The dark matter [...]Fri, Apr 13, 2018Source: CiteULike Group Cosmo LUTHEDGES result versus CMB and low-redshift constraints on ionization histories(11 Apr 2018)We examine the results from the Experiment to Detect the Global Epoch of Reionization Signature (EDGES), which has recently claimed the detection of a strong absorption in the 21 cm hyperfine transition line of neutral hydrogen, at redshifts demarcating the early stages of star formation. More concretely, we [...]Thu, Apr 12, 2018Source: CiteULike Group Cosmo LUTHGalactic Outflows, Star Formation Histories, and Timescales in Starburst Dwarf Galaxies from STARBIRDS(29 Mar 2018)Winds are predicted to be ubiquitous in low-mass, actively star-forming galaxies. Observationally, winds have been detected in relatively few local dwarf galaxies, with even fewer constraints placed on their timescales. Here, we compare galactic outflows traced by diffuse, soft X-ray emission from Chandra Space Telescope archival observations to [...]Mon, Apr 02, 2018Source: CiteULike Group Cosmo LUTHInstability of Supersonic Cold Streams Feeding Galaxies II. Nonlinear Evolution of Surface and Body Modes of Kelvin-Helmholtz Instability(24 Mar 2018)As part of our long-term campaign to understand how cold streams feed massive galaxies at high redshift, we study the Kelvin-Helmholtz instability (KHI) of a supersonic, cold, dense gas stream as it penetrates through a hot, dilute circumgalactic medium (CGM). A linear analysis (Paper I) showed that, for [...]Wed, Mar 28, 2018Source: CiteULike Group Cosmo LUTHThe Extreme Faint End of the UV Luminosity Function at $zâˆ¼6$ Through Gravitational Telescopes: a comprehensive assessment of strong lensing uncertainties(26 Mar 2018)With the Hubble Frontier Fields program, gravitational lensing has provided a powerful way to extend the study of the ultraviolet luminosity function (LF) of galaxies at $z ∼ 6$ down to unprecedented magnitude limits. At the same time, significant discrepancies between different studies were found at the very [...]Wed, Mar 28, 2018Source: CiteULike Group Cosmo LUTHResolving the hydrostatic mass profiles of galaxy clusters at z~1 with XMM-Newton and Chandra(20 Mar 2018)We present a detailed study of the integrated total hydrostatic mass profiles of the five most massive ($M_500 > 5 × 10^14 M_odot$) galaxy clusters selected at z$∼$1 via the Sunyaev-Zel'dovich effect. These objects represent an ideal laboratory to test our models in a mass regime where structure [...]Wed, Mar 21, 2018Source: CiteULike Group Cosmo LUTHLikelihood Non-Gaussianity in Large-Scale Structure Analyses(16 Mar 2018)Standard present day large-scale structure (LSS) analyses make a major assumption in their Bayesian parameter inference --- that the likelihood has a Gaussian form. For summary statistics currently used in LSS, this assumption, even if the underlying density field is Gaussian, cannot be correct in detail. We investigate [...]Tue, Mar 20, 2018Source: CiteULike Group Cosmo LUTHProbing the nature of Dark Matter through the metal enrichment of the intergalactic medium(14 Mar 2018)We focus on exploring the metal enrichment of the intergalactic medium (IGM) in Cold and Warm (1.5 and 3 keV) Dark Matter (DM) cosmologies, and the constraints this yields on the DM particle mass, using a semi-analytic model, Delphi, that jointly tracks the Dark Matter and baryonic assembly [...]Fri, Mar 16, 2018Source: CiteULike Group Cosmo LUTHChaos and Variance in Galaxy Formation(14 Mar 2018)The evolution of galaxies is governed by equations with chaotic solutions: gravity and compressible hydrodynamics. While this micro-scale chaos and stochasticity has been well studied, it is poorly understood how it couples to macro-scale properties examined in simulations of galaxy formation. In this paper, we show how perturbations [...]Fri, Mar 16, 2018Source: CiteULike Group Cosmo LUTHEvolution of axis ratios from phase space dynamics of triaxial collapse(8 Mar 2018)We investigate the evolution of axis ratios of triaxial haloes using the phase space description of triaxial collapse. In this formulation, the evolution of the triaxial ellipsoid is described in terms of the dynamics of eigenvalues of three important tensors: the Hessian of the gravitational potential, the tensor [...]Fri, Mar 09, 2018Source: CiteULike Group Cosmo LUTHMerger history of central galaxies in Semi-Analytic Models of galaxy formation(6 Mar 2018)We investigate the dynamical evolution of galaxies in groups with different formation epochs. Galaxy groups have been selected to be in different dynamical states, namely dynamically old and dynamically young, which reflect their early and late formation times, respectively, based on their halo mass assembly. Brightest galaxies in [...]Thu, Mar 08, 2018Source: CiteULike Group Cosmo LUTHThe accuracy of semi-numerical reionization models in comparison with radiative transfer simulations(28 Feb 2018)We have developed a modular semi-numerical code that computes the time and spatially dependent ionization of neutral hydrogen (HI), neutral (HeI) and singly ionized helium (HeII) in the intergalactic medium (IGM). The model accounts for recombinations and provides different descriptions for the photoionization rate that are used to [...]Fri, Mar 02, 2018Source: CiteULike Group Cosmo LUTHDusty galaxies in the Epoch of Reionization: simulations(21 Feb 2018)The recent discovery of dusty galaxies well into the Epoch of Reionization (redshift $z>6$) poses challenging questions about the properties of the interstellar medium in these pristine systems. By combining state-of-the-art hydrodynamic and dust radiative transfer simulations, we address these questions focusing on the recently discovered dusty galaxy [...]Fri, Feb 23, 2018Source: CiteULike Group Cosmo LUTHReconstruction of the two-dimensional gravitational potential of galaxy clusters from X-ray and Sunyaev-Zel'dovich measurements(20 Feb 2018)The mass of galaxy clusters is not a direct observable, nonetheless it is commonly used to probe cosmological models. Based on the combination of all main cluster observables, that is, the X-ray emission, the thermal Sunyaev-Zel'dovich (SZ) signal, the velocity dispersion of the cluster galaxies, and gravitational lensing, [...]Wed, Feb 21, 2018Source: CiteULike Group Cosmo LUTHThe Cosmic Web Around The Brightest Galaxies During The Epoch Of Reionization(19 Feb 2018)The most luminous galaxies at high-redshift are generally considered to be hosted in massive dark-matter halos of comparable number density, hence residing at the center of overdensities/protoclusters. We assess the validity of this assumption by investigating the clustering around the brightest galaxies populating the cosmic web at redshift [...]Wed, Feb 21, 2018Source: CiteULike Group Cosmo LUTHGlobular Clusters in High-Redshift Dwarf Galaxies: A Case Study from the Local Group(19 Feb 2018)We present the reconstructed evolution of rest-frame ultra-violet (UV) luminosities of the most massive Milky Way dwarf spheroidal satellite galaxy, Fornax, and its five globular clusters (GCs) across redshift, based on analysis of the stellar fossil record and stellar population synthesis modeling. We find that (1) Fornax's (proto-)GCs [...]Wed, Feb 21, 2018Source: CiteULike Group Cosmo LUTHStar-forming galaxies are predicted to lie on a fundamental plane of mass, star formation rate and Î±-enhancement(19 Feb 2018)Observations show that star-forming galaxies reside on a tight three-dimensional plane between mass, gas-phase metallicity and star formation rate (SFR), which can be explained by the interplay between metal-poor gas inflows and SFR. However, different metals are released on different time-scales, which may affect this relation. Here, we [...]Wed, Feb 21, 2018Source: CiteULike Group Cosmo LUTHObscured star-formation in bright z ~ 7 Lyman-break galaxies(15 Feb 2018)We present Atacama Large Millimeter/Submillimeter Array observations of the rest-frame far-infrared (FIR) dust continuum emission of six bright Lyman-break galaxies (LBGs) at $z ∼eq 7$. The average FIR luminosity of the sample is found to be $L_ FIR ∼eq 2 × 10^11\, L_odot$, corresponding to an obscured star-formation [...]Mon, Feb 19, 2018Source: CiteULike Group Cosmo LUTHGravitational Redshifts in Clusters and Voids(14 Feb 2018)Gravitational redshift as a relativistic effect in cosmological objects is investigated. Possible signatures of the gravitational redshift in measurements of satellite galaxies in clusters of galaxies, intracluster gas, as well as galaxies associated with voids are investigated by developing simple theoretical models. In the analysis of the gravitational [...]Thu, Feb 15, 2018Source: CiteULike Group Cosmo LUTHDark-ages Reionization and Galaxy Formation Simulation - XIV. Gas accretion, cooling and star formation in dwarf galaxies at high redshift(12 Feb 2018)We study dwarf galaxy formation at high redshift ($z≥5$) using a suite of high-resolution, cosmological hydrodynamic simulations and a semi-analytic model (SAM). We focus on gas accretion, cooling and star formation in this work by isolating the relevant process from reionization and supernova feedback, which will be further [...]Tue, Feb 13, 2018Source: CiteULike Group Cosmo LUTHCosmological simulation with dust formation and destruction(12 Feb 2018)To investigate the evolution of dust in a cosmological volume, we perform hydrodynamic simulations, in which the enrichment of metals and dust is treated self-consistently with star formation and stellar feedback. We consider dust evolution driven by dust production in stellar ejecta, dust destruction by sputtering, grain growth [...]Tue, Feb 13, 2018Source: CiteULike Group Cosmo LUTHReignition of Star Formation in Dwarf Galaxies(8 Feb 2018)The Local Group hosts a number of star-forming dwarf galaxies that show evidence of periods of little to no star formation. We use a suite of cosmological simulations to study how star formation is reignited in such galaxies. We focus on isolated galaxies at $z=0$ with halo masses [...]Mon, Feb 12, 2018Source: CiteULike Group Cosmo LUTHEnvironmental Quenching of Low-Mass Field Galaxies(8 Feb 2018)In the local Universe, there is a strong division in the star-forming properties of low-mass galaxies, with star formation largely ubiquitous amongst the field population while satellite systems are predominantly quenched. This dichotomy implies that environmental processes play the dominant role in suppressing star formation within this low-mass [...]Mon, Feb 12, 2018Source: CiteULike Group Cosmo LUTHThe Inhomogeneous Reionization Times of Present-day Galaxies(5 Feb 2018)Today's galaxies experienced cosmic reionization at different times in different locations. For the first time, reionization ($50\%$ ionized) redshifts, $z_R$, at the location of their progenitors are derived from new, fully-coupled radiation-hydrodynamics simulation of galaxy formation and reionization at $z > 6$, matched to N-body simulation to z [...]Wed, Feb 07, 2018Source: CiteULike Group Cosmo LUTHUnveiling Galaxy Bias via the Halo Model, KiDS and GAMA(2 Feb 2018)We measure the projected galaxy clustering and galaxy-galaxy lensing signals using the Galaxy And Mass Assembly (GAMA) survey and Kilo-Degree Survey (KiDS) to study galaxy bias. We use the concept of non-linear and stochastic galaxy biasing in the framework of halo occupation statistics to constrain the parameters of [...]Mon, Feb 05, 2018Source: CiteULike Group Cosmo LUTHFirstLight II: Star formation rates of primeval galaxies from z=5-15(31 Jan 2018)In the FirstLight project, we have used ~300 cosmological, zoom-in simulations to determine the star-formation histories of distinct first galaxies with stellar masses between Ms=10^6 and 3 x 10^9 Msun during cosmic dawn (z=5-15). The evolution of the star formation rate (SFR) in each galaxy is complex and [...]Thu, Feb 01, 2018Source: CiteULike Group Cosmo LUTHExploring Simulated Early Star Formation in the Context of the Ultrafaint Dwarf Galaxies(25 Jan 2018)Ultrafaint dwarf galaxies (UFDs) are typically assumed to have simple, stellar populations with star formation ending at reionization. Yet as the observations of these galaxies continue to improve, their star formation histories (SFHs) are revealed to be more complicated than previously thought. In this paper, we study how [...]Mon, Jan 29, 2018Source: CiteULike Group Cosmo LUTHDynamical constraints on the dark matter distribution of the Sculptor dwarf spheroidal from stellar proper motions(22 Jan 2018)We compare the transverse velocity dispersions recently measured within the Sculptor dwarf spheroidal galaxy to the predictions of previously published dynamical models. These provide good fits to the observed number count and velocity dispersion profiles of metal-rich and metal-poor stars both in cored and in cusped potentials. At [...]Thu, Jan 25, 2018Source: CiteULike Group Cosmo LUTHThe SPHINX Cosmological Simulations of the First Billion Years: the Impact of Binary Stars on Reionization(22 Jan 2018)We present the SPHINX suite of cosmological adaptive mesh refinement simulations, the first radiation-hydrodynamical simulations to simultaneously capture large-scale reionization and the escape of ionizing radiation from thousands of resolved galaxies. Our $5$ and $10$ co-moving Mpc volumes resolve haloes down to the atomic cooling limit and model [...]Thu, Jan 25, 2018Source: CiteULike Group Cosmo LUTHEvidence of a non universal stellar Initial Mass Function. Insights from HST optical imaging of 6 Ultra Faint Dwarf Milky Way Satellites(18 Jan 2018)Using deep HST/ACS observations, we demonstrate that the sub-solar stellar initial mass function (IMF) of 6 ultra-faint dwarf Milky Way Satellites (UFDs) is more bottom light than the IMF of the Milky Way disk. Our data have a lower mass limit of about 0.45 M$_odot$, while the upper [...]Mon, Jan 22, 2018Source: CiteULike Group Cosmo LUTHNo Assembly Required: Mergers are Mostly Irrelevant for the Growth of Low-mass Dwarf Galaxies(18 Jan 2018)We investigate the merger histories of isolated dwarf galaxies based on a suite of 15 high-resolution cosmological zoom-in simulations, all with masses of $M_ halo ≈ 10^10\, M_odot$ (and M$_∗∼10^5-10^7\, M_odot$) at $z=0$, from the Feedback in Realistic Environments (FIRE) project. The stellar populations of these dwarf galaxies [...]Mon, Jan 22, 2018Source: CiteULike Group Cosmo LUTHPushing back the limits: detailed properties of dwarf galaxies in a LCDM universe(18 Jan 2018)We present the results of a set of high resolution chemo-dynamical simulations of dwarf galaxies in a $Λ$CDM cosmology. Out of an original 3.4 Mpc$^3$/h$^3$ cosmological box, a sample of 27 systems are zoomed-in from z=70 to z=0. Gas and stellar properties are confronted to the observations in [...]Mon, Jan 22, 2018Source: CiteULike Group Cosmo LUTHBeyond Falsifiability: Normal Science in a Multiverse(15 Jan 2018)Cosmological models that invoke a multiverse - a collection of unobservable regions of space where conditions are very different from the region around us - are controversial, on the grounds that unobservable phenomena shouldn't play a crucial role in legitimate scientific theories. I argue that the way we [...]Wed, Jan 17, 2018Source: CiteULike Group Cosmo LUTHConsistent modelling of the meta-galactic UV background and the thermal/ionization history of the intergalactic medium(15 Jan 2018)Recent observations suggest that hydrogen reionization ends late ($z ∼eq 6$) and proceeds quickly. We present here a new model of the meta-galactic UV/X-ray background (UVB) that is consistent with this. It adopts the most recent determinations of the ionizing emissivity due to stars and AGN, as well [...]Wed, Jan 17, 2018Source: CiteULike Group Cosmo LUTHA Radio Continuum Study of Dwarf Galaxies: 6 cm imaging of Little Things(16 Jan 2018)In this paper we examine to what extent the radio continuum can be used as an extinction free probe of star formation in dwarf galaxies. To that aim we observe $40$ nearby dwarf galaxies with the Very Large Array at 6 cm ($4$-$8$ GHz) in C-configuration. We obtained [...]Wed, Jan 17, 2018Source: CiteULike Group Cosmo LUTHImpact of Lyman alpha pressure on metal-poor dwarf galaxies(15 Jan 2018)Understanding the origin of strong galactic outflows and the suppression of star formation in dwarf galaxies is a key problem in galaxy formation. Using a set of radiation-hydrodynamic simulations of an isolated dwarf galaxy embedded in a $10^10\,M_odot$ halo, we show that the momentum transferred from resonantly scattered [...]Wed, Jan 17, 2018Source: CiteULike Group Cosmo LUTHBlueTides simulation: establishing black hole-galaxy relations at high-redshift(15 Jan 2018)The scaling relations between the mass of supermassive black holes ($M_•$) and host galaxy properties (stellar mass, $M_∗$, and velocity dispersion, $σ$), provide a link between the growth of black holes (BHs) and that of their hosts. Here we investigate if and how the BH-galaxy relations are established [...]Wed, Jan 17, 2018Source: CiteULike Group Cosmo LUTHCool-Core Clusters : Role of BCG, Star Formation & AGN-Driven Turbulence(12 Jan 2018)Recent analysis shows that it is important to explicitly include the gravitational potential of the central brightest central galaxy (BCG) to infer the acceleration due to gravity ($g$) and the free-fall time ($t_ ff ≡ [2r/g]^1/2$) in cool cluster cores. Accurately measuring $t_ ff$ is crucial because according [...]Tue, Jan 16, 2018Source: CiteULike Group Cosmo LUTHOn the Appearance of Thresholds in the Dynamical Model of Star Formation(13 Jan 2018)The Kennicutt-Schmidt (KS) relationship between the surface density of the star formation rate (SFR) and the gas surface density has three distinct power laws that may result from one model in which gas collapses at a fixed fraction of the dynamical rate. The power law slope is 1 [...]Tue, Jan 16, 2018Source: CiteULike Group Cosmo LUTHSemi-Analytic Galaxies - I. Synthesis of environmental and star-forming regulation mechanisms(11 Jan 2018)We present results from the semi-analytic model of galaxy formation SAG applied on the MultiDark simulation MDPL2. SAG features an updated supernova (SN) feedback scheme and a robust modelling of the environmental effects on satellite galaxies. This incorporates a gradual starvation of the hot gas halo driven by [...]Fri, Jan 12, 2018Source: CiteULike Group Cosmo LUTHGalaxy Formation in Sterile Neutrino Dark Matter Models(11 Jan 2018)We investigate galaxy formation in models with dark matter (DM) constituted by sterile neutrinos. Given their large parameter space, defined by the combinations of sterile neutrino mass $m_ν$ and mixing parameter $\sin^2(2θ)$ with active neutrinos, we focus on models with $m_ν=7$ keV, consistent with the tentative 3.5 keV [...]Fri, Jan 12, 2018Source: CiteULike Group Cosmo LUTH