A5042981887- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Cosmology and Gravitation Theories
- Dark Matter and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Scientific Research and Discoveries
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Particle physics theoretical and experimental studies
- Astrophysical Phenomena and Observations
- Black Holes and Theoretical Physics
- Remote Sensing in Agriculture
- Phase Equilibria and Thermodynamics
- Geomagnetism and Paleomagnetism Studies
- Plant Water Relations and Carbon Dynamics
- Mathematical Dynamics and Fractals
- Gambling Behavior and Treatments
- Geophysics and Gravity Measurements
- Career Development and Diversity
- Advanced Differential Equations and Dynamical Systems
- Digital Games and Media
Liverpool John Moores University
2015-2024
Max Planck Institute for Astronomy
2019
Max Planck Society
2019
University of Cambridge
2011-2013
University of Birmingham
2012-2013
Institute of Astronomy
2011-2012
Netherlands Institute for Radio Astronomy
2012
Central University of Venezuela
2000-2011
Durham University
2007-2011
Wesleyan University
2005-2008
We use a large suite of carefully controlled full hydrodynamic simulations to study the ram pressure stripping hot gaseous haloes galaxies as they fall into massive groups and clusters. The sensitivity results orbit, total galaxy mass, structural properties is explored. For typical orbital parameters, we find that ∼30 per cent initial galactic halo gas can remain in place after 10 Gyr. propose physically simple analytic model describes seen remarkably well. analogous original formulation...
Current models of galaxy formation predict satellite galaxies in groups and clusters that are redder than observed. We investigate the effect on colours produced by ram pressure stripping their hot gaseous atmospheres as satellites orbit within parent halo. incorporate a model process based detailed hydrodynamic simulations Durham semi-analytic formation. The show environment is less aggressive previously assumed. main uncertainty treatment gas expelled supernovae. With reasonable...
We use the Galaxies-Intergalactic Medium Interaction Calculation (GIMIC) suite of cosmological hydrodynamical simulations to study formation stellar spheroids Milky Way-mass disc galaxies. The contain accurate treatments metal-dependent radiative cooling, star formation, supernova feedback, and chemodynamics, large volumes that have been simulated yield an unprecedentedly sample ~400 L_* galaxies are surrounded by low-mass, low-surface brightness haloes extend out ~100 kpc beyond. diffuse...
In the local Universe, galaxies in groups and clusters contain less gas are likely to be forming stars than their field counterparts. This effect is not limited central group/cluster regions, but shown by recent observations persist out several virial radii. To gain insight into extent cause of this large-scale environmental influence, we use a suite high-resolution cosmological hydrodynamic simulations analyse around simulated wide range mass (log M/M_sun = [13.0, 15.2]). qualitative...
This paper explores the mapping between observable properties of a stellar halo in phase- and abundance-space parent galaxy's accretion history terms characteristic epoch mass orbits progenitor objects. The study utilizes suite eleven models constructed within context standard LCDM cosmology. results demonstrate that coordinate-space studies are sensitive to recent (0-8 Gyears ago) merger histories galaxies (this timescale corresponds last few tens percent for Milky-Way-type galaxy)....
We examine the ability of photoevaporative disk winds to explain low-velocity components observed in forbidden line spectra low-mass T Tauri stars. Using analytic model Shu and coworkers Hollenbach as a basis, we characteristics outflows with hydrodynamic simulations. General results from simulations agree well predictions, although some small differences are present. Most importantly, flow material surface develops at smaller radii than approximations, velocity is only one-third sound...
We use the galaxy stellar mass and halo merger tree information from semi-analytic model catalogue of Font et al. to examine accretion galaxies into a large sample groups clusters, covering wide range in (1012.9 1015.3h−1 M⊙), selected each four redshift epochs (z= 0, 0.5, 1.0 1.5). find that clusters at all examined redshifts have accreted significant fraction their final populations through groups. A 1014.5h−1 M⊙ cluster z= 0 has, on average, ∼40 per cent its (Mstellar > 109h−1 M⊙) haloes...
The hierarchical formation scenario for the stellar halo requires accretion and disruption of dwarf galaxies, yet low-metallicity stars are enriched in α-elements compared to similar, spheroidal (dSph) galaxies. We address this primary challenge by combining chemical evolution modeling with cosmologically motivated mass histories Milky Way dark its satellites. demonstrate that galaxy abundance patterns can be explained naturally within ΛCDM framework. Our solution relies fundamentally on...
We present a cosmologically motivated model for the hierarchical formation of stellar halo that includes semianalytic treatment galactic chemical enrichment coupled to numerical simulations track orbital evolution and tidal disruption satellites. A major motivating factor in this investigation is observed systematic difference between abundances stars satellite galaxies those Milky Way halo. Specifically, same [Fe/H] values, neighboring display significantly lower [α/Fe] ratios than find...
Recent studies have presented evidence for tension between the constraints on Ωm and σ8 from cosmic microwave background (CMB) measurements of large-scale structure (LSS). This can potentially be resolved by appealing to extensions standard model cosmology and/or untreated systematic errors in modelling LSS, which baryonic physics has been frequently suggested. We revisit this using, first time, carefully calibrated cosmological hydrodynamical simulations, thus capture backreaction baryons...
We present a model for the satellites of Milky Way in which galaxy formation is followed using semi-analytic techniques applied to six high-resolution N-body simulations galactic halos Aquarius project. The model, calculated Galform code, incorporates improved treatments relevant physics LambdaCDM cosmogony, particularly self-consistent calculation reionization by UV photons emitted forming population, including progenitors central galaxy. Along merger tree each halo, calculates gas cooling...
We quantify the correlations between gas-phase and stellar metallicities global properties of galaxies, such as mass, halo age gas fraction, in Evolution Assembly GaLaxies their Environments (EAGLE) suite cosmological hydrodynamical simulations. The slope correlation mass metallicity star-forming (SF) ($M_*-Z_{\rm SF,gas}$ relation) depends somewhat on resolution, with higher-resolution run reproducing a steeper slope. This simulation predicts non-zero evolution, increasing by $\approx 0.5$...
We use the Galaxies-Intergalactic Medium Interaction Calculation (GIMIC) suite of cosmological hydrodynamical simulations to study global structure and kinematics stellar spheroids Milky Way mass disc galaxies. Font et al. have recently demonstrated that these are able successfully reproduce satellite luminosity functions metallicity surface brightness profiles M31. A key success is a significant contribution spheroid from stars formed in situ. While outer halo dominated by accreted stars,...
We introduce the ARTEMIS simulations, a new set of 42 zoomed-in, high-resolution (baryon particle mass ~ 2x10^4 Msun/h), hydrodynamical simulations galaxies residing in haloes Milky Way mass, simulated with EAGLE galaxy formation code re-calibrated stellar feedback. In this study, we analyse structure haloes, specifically density, surface brightness, metallicity, colour and age radial profiles, finding generally very good agreement recent observations local galaxies. The density profiles are...
Using the ARTEMIS set of 45 high-resolution cosmological simulations, we investigate a range merger-induced dynamical transformations Milky Way-like galaxies. We first identify populations accreted stars on highly radial orbits, similar to 'Gaia Sausage' in Way. show that $\approx1/3$ galaxies contain feature, and confirm they usually comprise stellar debris from most massive satellite. Selecting 15 with discs at present-day, study their changes around times GS-like mergers. Dark matter...
Upcoming large-scale structure surveys will measure the matter power spectrum to approximately percent level accuracy with aim of searching for evidence new physics beyond standard model cosmology. In order avoid biasing our conclusions, theoretical predictions need be at least as accurate measurements a given choice cosmological parameters. However, recent work has shown that complex physical processes associated galaxy formation (particularly energetic feedback stars and especially...
[Abridged] Motivated by upcoming data from astrometric and spectroscopic surveys of the Galaxy, we explore chemical abundance properties phase-space distributions in hierarchically-formed stellar halo simulations set a LambdaCDM Universe. Our sample Milky-Way type result average metallicities that range [Fe/H] = -1.3 to -0.9, with most metal poor halos resulting accretion histories lack destructive mergers massive (metal rich) satellites. increase mass. The slope [Fe/H]-stellar mass trend...
We study the phase-space distribution of satellite galaxies associated with late-type in gimic suite simulations. consists resimulations five cosmologically representative regions from Millennium Simulation, which have higher resolution and incorporate baryonic physics. Whilst disc galaxy is well aligned inner (r∼ 0.1r200) dark matter halo, both shape angular momentum, there can be substantial misalignments at larger radii (r∼r200). Misalignments >45° are seen ∼30 per cent our sample. find...
We combine the six high-resolution Aquarius dark matter simulations with a semi-analytic galaxy formation model to investigate properties of satellites Milky Way-like galaxies. find good correspondence observed luminosity function, luminosity-metallicity relation and radial distribution Way satellites. The star histories dwarf galaxies in our vary widely, accordance what is seen observationally. Ram-pressure stripping hot gas from leaves clear imprint environment on characteristics galaxy....
ABSTRACT The vast majority of low-mass satellite galaxies around the Milky Way and M31 appear virtually devoid cool gas show no signs recent or ongoing star formation. Cosmological simulations demonstrate that such quenching is expected due to harsh environmental conditions satellites face when joining Local Group (LG). However, observations analogues in SAGA survey present a very different picture, showing observed be actively forming stars, calling into question realism current typicality...
ABSTRACT A number of recent studies have found evidence for a tension between observations large-scale structure (LSS) and the predictions standard model cosmology with cosmological parameters fit to cosmic microwave background (CMB). The origin this ‘S8 tension’ remains unclear, but possibilities include new physics beyond model, unaccounted systematic errors in observational measurements and/or uncertainties role that baryons play. Here, we carefully examine latter possibility using...
We present a comparison of 14 galaxy formation models: 12 different semi-analytical models and 2 halo occupation distribution for based upon the same cosmological simulation merger tree information derived from it. The participating codes have proven to be very successful in their own right but they all been calibrated independently using various observational data sets, stellar models, trees. In this paper, we apply them without recalibration leads wide variety predictions mass function,...
The recent advent of deep observational surveys local Milky Way `analogues' and their satellite populations allows us to place the in a broader cosmological context test models galaxy formation on small scales. In present study, we use LCDM-based ARTEMIS suite hydrodynamical simulations containing 45 analogue host haloes make comparisons observed luminosity functions, radial distribution abundance scaling relations from Local Volume SAGA surveys, addition M31. We find that, contrary some...
We examine recent suggestions that substructure in cold dark matter (CDM) halos may be conflict with the presence of thin, dynamically fragile stellar disks. N-body simulations an isolated disk/bulge/halo model Milky Way includes several hundred satellites masses, densities, and orbits derived from high-resolution cosmological CDM indicate at z = 0 plays only a minor dynamical role heating disk over gigayears. This is because present-day seldom take them near disk, where their tidal effects...
We examine the nature of progenitor giant stellar stream in M31 using as constraints new radial velocity measurements red stars (presented companion paper by Guhathakurta and coworkers) along with other data sets available literature. find that observations are best fitted orbits highly eccentric close to edge-on, apocenter pericenter ratios on order 25-30 apocenters at or only slightly beyond southern edge current data. Among these we able a few plausibly connect northern spur low surface...