The Horizon Run 5 Cosmological Hydrodynamical Simulation: Probing Galaxy Formation from Kilo- to Gigaparsec Scales

ABSTRACT We present an analysis of the matter, halo, and galaxy clustering in f(R)-gravity employing the SHYBONE full-physics hydrodynamical simulation suite. Our analysis focuses on the interplay between baryonic feedback and f(R)-gravity in the matter power spectrum, the matter and halo correlation functions, the halo and galaxy–host–halo mass function, the subhalo and satellite–galaxy count, and the correlation function of the stars in our simulations. Our studies of the matter power spectrum in full-physics simulations in f(R)-gravity show that it will be very difficult to derive accurate fitting formulae for the power spectrum enhancement in f(R)-gravity which include baryonic effects. We find that the enhancement of the halo mass function due to f(R)-gravity and its suppression due to feedback effects do not show significant back-reaction effects and can thus be estimated from independent general relativity-hydro and f(R) dark matter only simulations. Our simulations furthermore show that the number of subhaloes and satellite-galaxies per halo is not significantly affected by f(R)-gravity. Low-mass haloes are nevertheless more likely to be populated by galaxies in f(R)-gravity. This suppresses the clustering of stars and the galaxy correlation function in the theory compared to standard cosmology.

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Joint galaxy–galaxy lensing and clustering constraints on galaxy formation

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2675 ◽

2020 ◽

Vol 498 (4) ◽

pp. 5804-5833

Author(s):

Malin Renneby ◽

Bruno M B Henriques ◽

Stefan Hilbert ◽

Dylan Nelson ◽

Mark Vogelsberger ◽

...

Keyword(s):

Galaxy Formation ◽

Group Membership ◽

Stellar Mass ◽

Current Data ◽

Theoretical Development ◽

High Mass ◽

Intermediate Mass ◽

Hydrodynamical Simulation ◽

Low Mass ◽

Red Galaxies

ABSTRACT We compare predictions for galaxy–galaxy lensing profiles and clustering from the Henriques et al. public version of the Munich semi-analytical model (SAM) of galaxy formation and the IllustrisTNG suite, primarily TNG300, with observations from KiDS + GAMA and SDSS-DR7 using four different selection functions for the lenses (stellar mass, stellar mass and group membership, stellar mass and isolation criteria, and stellar mass and colour). We find that this version of the SAM does not agree well with the current data for stellar mass-only lenses with $M_\ast \gt 10^{11}\, \mathrm{ M}_\odot$. By decreasing the merger time for satellite galaxies as well as reducing the radio-mode active galactic nucleus accretion efficiency in the SAM, we obtain better agreement, both for the lensing and the clustering, at the high-mass end. We show that the new model is consistent with the signals for central galaxies presented in Velliscig et al. Turning to the hydrodynamical simulation, TNG300 produces good lensing predictions, both for stellar mass-only (χ2 = 1.81 compared to χ2 = 7.79 for the SAM) and locally brightest galaxy samples (χ2 = 3.80 compared to χ2 = 5.01). With added dust corrections to the colours it matches the SDSS clustering signal well for red low-mass galaxies. We find that both the SAMs and TNG300 predict $\sim 50\, {{\ \rm per\ cent}}$ excessive lensing signals for intermediate-mass red galaxies with 10.2 < log10M*[M⊙] < 11.2 at $r \approx 0.6\, h^{-1}\, \text{Mpc}$, which require further theoretical development.

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horizon-AGN virtual observatory – 2. Template-free estimates of galaxy properties from colours

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2486 ◽

2019 ◽

Vol 489 (4) ◽

pp. 4817-4835 ◽

Cited By ~ 5

Author(s):

I Davidzon ◽

C Laigle ◽

P L Capak ◽

O Ilbert ◽

D C Masters ◽

...

Keyword(s):

Galaxy Formation ◽

Formation Rate ◽

Broad Band ◽

Self Organizing Maps ◽

Galaxy Surveys ◽

Hydrodynamical Simulation ◽

Calibration Sample ◽

Data Driven Approach ◽

Template Free ◽

Tight Correlation

ABSTRACT Using the horizon-AGN hydrodynamical simulation and self-organizing maps (SOMs), we show how to compress the complex, high-dimensional data structure of a simulation into a 2D grid, which greatly facilitates the analysis of how galaxy observables are connected to intrinsic properties. We first verify the tight correlation between the observed 0.3–5 μm broad-band colours of horizon-AGN galaxies and their high-resolution spectra. The correlation is found to extend to physical properties such as redshift, stellar mass, and star formation rate (SFR). This direct mapping from colour to physical parameter space still works after including photometric uncertainties that mimic the COSMOS survey. We then label the SOM grid with a simulated calibration sample to estimate redshift and SFR for COSMOS-like galaxies up to z ∼ 3. In comparison to state-of-the-art techniques based on synthetic templates, our method is comparable in performance but less biased at estimating redshifts, and significantly better at predicting SFRs. In particular, our ‘data-driven’ approach, in contrast to model libraries, intrinsically allows for the complexity of galaxy formation and can handle sample biases. We advocate that observations to calibrate this method should be one of the goals of next-generation galaxy surveys.

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How well is angular momentum accretion modelled in semi-analytic galaxy formation models?

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab2454 ◽

2021 ◽

Author(s):

Jun Hou ◽

Cedric G Lacey ◽

Carlos S Frenk

Keyword(s):

Angular Momentum ◽

Galaxy Formation ◽

Moving Mesh ◽

Important Process ◽

Metal Enrichment ◽

Accretion Process ◽

Hydrodynamical Simulation ◽

Gas Cooling ◽

The Mean ◽

Cooling Model

Abstract Gas cooling and accretion in haloes delivers mass and angular momentum on to galaxies. In this work, we investigate the accuracy of the modelling of this important process in several different semi-analytic (SA) galaxy formation models (galform , l-galaxies and morgana ) through comparisons with a hydrodynamical simulation performed with the moving-mesh code arepo . Both SA models and the simulation were run without any feedback or metal enrichment, in order to focus on the cooling and accretion process. All of the SA models considered here assume that gas cools from a spherical halo. We found that the assumption that the gas conserves its angular momentum when moving from the virial radius, rvir, to the central region of the halo, r ∼ 0.1rvir, is approximately consistent with the results from our simulation. We also found that, compared to the simulation, the morgana model tends to overestimate the mean specific angular momentum of cooled-down gas, the l-galaxies model also tends to overestimate this in low-redshift massive haloes, while the two older galform models tend to underestimate the angular momentum. In general, the predictions of the new galform cooling model developed by Hou et al. agree agree the best with the simulation.

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The frequency of very young galaxies in the local Universe – II. The view from SDSS spectra

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3556 ◽

2019 ◽

Vol 492 (2) ◽

pp. 1791-1811 ◽

Cited By ~ 5

Author(s):

Gary A Mamon ◽

Marina Trevisan ◽

Trinh X Thuan ◽

Anna Gallazzi ◽

Romeel Davé

Keyword(s):

Star Formation ◽

Galaxy Formation ◽

Analytical Models ◽

Local Universe ◽

M 10 ◽

Hydrodynamical Simulation ◽

Spectral Models ◽

Galaxy Sample ◽

Stellar Masses ◽

Star Formation Histories

ABSTRACT Only a handful of galaxies in the local Universe appear to be very young. We estimate the fraction of very young galaxies (VYGs), defined as those with more than half their stellar masses formed within the last Gyr. We fit non-parametric star formation histories (SFHs) to ∼280 000 galaxy spectra from a flux- and volume-limited subsample of the Main Galaxy Sample (MGS) of the SDSS, which is also complete in mass-to-light ratio, thus properly accounting for passive galaxies of a given mass. The VYG fractions decrease with increasing galaxy stellar mass, from ∼50 per cent at $m = 10^8\, {\rm M}_{\odot }$ to ∼0.1 per cent at $m = 10^{11.5}\, {\rm M}_{\odot }$, with differences of up to 1 dex between the different spectral models used to estimate the SFH and on how we treat aperture effects. But old stellar populations may hide in our VYGs despite our conservative VYG sample built with galaxies that are globally bluer than within the region viewed by the SDSS fibre. The VYG fractions versus mass decrease more gradually compared to the Tweed et al. predictions using analytical and semi-analytical models of galaxy formation, but agree better with the SIMBA hydrodynamical simulation. These discrepancies highlight the usefulness of VYGs in constraining the strong uncertainties in both galaxy formation models and spectral modelling of galaxy SFHs. Given the lognormal cosmic SFH, these mean VYG fractions suggest that galaxies above $10^8\, \rm M_\odot$ undergo at most four major starbursts on average.

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The APOSTLE simulations: Rotation curves derived from synthetic 21-cm observations

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317006615 ◽

2017 ◽

Vol 13 (S334) ◽

pp. 213-218

Author(s):

Kyle A. Oman

Keyword(s):

Dark Matter ◽

Galaxy Formation ◽

Cold Dark Matter ◽

Local Group ◽

Synthetic Data ◽

Formation Model ◽

Rotation Curves ◽

Hydrodynamical Simulation ◽

The Galaxy ◽

Spectrally Resolved

AbstractThe apostle cosmological hydrodynamical simulation suite is a collection of twelve regions ~5 Mpc in diameter, selected to resemble the Local Group of galaxies in terms of kinematics and environment, and re-simulated at high resolution (minimum gas particle mass of 104 M⊙) using the galaxy formation model and calibration developed for the eagle project. I select a sample of dwarf galaxies (60 < Vmax/km s−1 < 120) from these simulations and construct synthetic spatially- and spectrally-resolved observations of their 21-cm emission. Using the 3Dbarolo tilted-ring modelling tool, I extract rotation curves from the synthetic data cubes. In many cases, non-circular motions present in the gas disc hinder the recovery of a rotation curve which accurately traces the underlying mass distribution; a large central deficit of dark matter, relative to the predictions of cold dark matter N-body simulations, may then be erroneously inferred.

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A high-resolution cosmological simulation of a strong gravitational lens

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa4013 ◽

2021 ◽

Author(s):

Jack Richings ◽

Carlos Frenk ◽

Adrian Jenkins ◽

Andrew Robertson ◽

Matthieu Schaller

Keyword(s):

Dark Matter ◽

Galaxy Formation ◽

Cold Dark Matter ◽

Median Number ◽

Gravitational Lens ◽

Galactic Winds ◽

Hydrodynamical Simulation ◽

Cold Dark Matter Model ◽

Lower Amplitude ◽

Mass Functions

Abstract We present a cosmological hydrodynamical simulation of a 1013 M⊙ galaxy group and its environment (out to 10 times the virial radius) carried out using the Eagle model of galaxy formation. Exploiting a novel technique to increase the resolution of the dark matter calculation independently of that of the gas, the simulation resolves dark matter haloes and subhaloes of mass 5 × 106 M⊙. It is therefore useful for studying the abundance and properties of the haloes and subhaloes targeted in strong lensing tests of the cold dark matter model. We estimate the halo and subhalo mass functions and discuss how they are affected both by the inclusion of baryons in the simulation and by the environment. We find that the halo and subhalo mass functions have lower amplitude in the hydrodynamical simulation than in its dark matter only counterpart. This reflects the reduced growth of haloes in the hydrodynamical simulation due to the early loss of gas by reionisation and galactic winds and, additionally, in the case of subhaloes, disruption by enhanced tidal effects within the host halo due to the presence of a massive central galaxy. The distribution of haloes is highly anisotropic reflecting the filamentary character of mass accretion onto the cluster. As a result, there is significant variation in the number of structures with viewing direction. The median number of structures near the centre of the halo, when viewed in projection, is reduced by a factor of two when baryons are included.

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The Lowest Metallicity Stars in the LMC: Clues from MaGICC Simulations

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2013.20 ◽

2013 ◽

Vol 30 ◽

Cited By ~ 1

Author(s):

Chris B. Brook ◽

Maider S. Miranda ◽

Brad. K. Gibson ◽

Kate Pilkington ◽

Greg S. Stinson

Keyword(s):

Star Formation ◽

Galaxy Formation ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Spatial Distributions ◽

Central Galaxy ◽

Hydrodynamical Simulation ◽

Inner Region ◽

Early Phases

AbstractUsing a cosmological hydrodynamical simulation of a galaxy of similar mass to the Large Magellanic Cloud (LMC), we examine the predicted characteristics of its lowest metallicity populations. In particular, we emphasise the spatial distributions of first (Pop III) and second (polluted by only immediate Pop III ancestors) generation stars. We find that primordial composition stars form not only in the central galaxy’s progenitor, but also in locally collapsed subhaloes during the early phases of galaxy formation. The lowest metallicity stars in these subhaloes end up in a relatively extended distribution around the host, with these accreted stars possessing present-day galactocentric distances as great as ~40 kpc. By contrast, the earliest stars formed within the central galaxy remain in the inner region, where the vast majority of star formation occurs, for the entirety of the simulation. Consequently, the fraction of stars that are from the earliest generation increases strongly with radius.

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The Metallicity Distribution in the Halo Stars of NGC 5128: Implications for Galaxy Formation

The Astronomical Journal ◽

10.1086/300749 ◽

1999 ◽

Vol 117 (2) ◽

pp. 855-867 ◽

Cited By ~ 98

Author(s):

Gretchen L. H. Harris ◽

William E. Harris ◽

Gregory B. Poole

Keyword(s):

Galaxy Formation ◽

Halo Stars ◽

Metallicity Distribution

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Galaxy Formation: Some Comparisons between Theory and Observation

Symposium - International Astronomical Union ◽

10.1017/s0074180900033350 ◽

1983 ◽

Vol 100 ◽

pp. 391-399 ◽

Cited By ~ 1

Author(s):

S. Michael Fall

Keyword(s):

Galaxy Formation ◽

Total Mass ◽

Virial Theorem ◽

Velocity Dispersion ◽

Rotation Velocity ◽

Morphological Type ◽

Fundamental Parameter ◽

Mass Ratio ◽

First Approximation ◽

Type Form

Before theoretical ideas in this subject can be compared with observational data, it is necessary to consider the properties of galaxies that are likely to be relics of their formation. Most astronomers would agree that the list of important parameters should be headed by the total mass M, energy E and angular momentum J. Next on the list should probably be the relative contributions to these quantities from the disc and bulge components of galaxies and denoted D/B for the mass ratio. They can be estimated from the median (i.e. half-mass) radius R, velocity dispersion σ and rotation velocity v of each component, either through the virial theorem or through the luminosity L and an assumed value of M/L. As a first approximation, it is reasonable to suppose that galaxies of a given disc-to-bulge ratio or morphological type form a sequence with mass as the fundamental parameter. The comparison of theory with data is further simplified by considering the extreme cases of ellipticals, with D/B << 1, and late-type spirals, with D/B >> 1. The approach outlined below is to explore the consequences of relaxing in succession the constraints that E, J and M be conserved during the collapse of proto-galaxies. In this article I concentrate on theories that are based on some form of hierarchical clustering because the pancake and related theories are not yet refined enough for a detailed confrontation with observations.

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