arXiv subjects

Volker Springel

Publications and source records attributed to Volker Springel.

At least 55 records · Page 3Linked to original sources

arXiv2025

Unveiling the Impact of Cosmic Rays on the Disc Sizes and Outflows from Dwarf Scales to Galaxy Groups

Cosmic rays (CRs) are a non-thermal energy component in the interstellar and circumgalactic medium (CGM) that can act as an additional feedback channel beyond thermal and kinetic feedback from stars and AGN. They influence galaxy evolution by altering gas properties, regulating star formation, and shaping galactic outflows. We investigate these effects using a suite of cosmological zoom-in simulations, which incorporate CR transport and feedback on top of the Auriga galaxy formation model. Our simulations span a wide range of halo masses, from dwarf galaxies to small groups ($M_{200\mathrm{c}}= 10^{10} - 10^{13}~\mathrm{M}_\odot$), allowing us to assess the mass-dependent impact of CRs in a cosmological setting. We find that CRs have the strongest impact in lower-mass galaxies ($M_{200\mathrm{c}} < 10^{12}~\mathrm{M}_\odot$), where they suppress star formation rates by up to 50\%, reduce gas and stellar half-light radii, and drive outflows that reach higher velocities at the virial radius compared to simulations without CRs. These CR-enhanced outflows also transport more metals and magnetic fields into the CGM, leading to higher CGM metallicities, stronger magnetisation, and lower CGM temperatures. In more massive galaxies, CRs do not significantly affect star formation or outflow properties, likely because thermal and kinetic feedback from stars and AGN dominate in this regime. However, CRs still influence galaxy morphology across all halo masses by reducing the gas half-mass radius and stellar half-light radius. Finally, variations in CR transport properties, such as different diffusion coefficients or the exclusion of Alfvén cooling, significantly affect star formation, CGM properties, and outflows in lower-mass galaxies. This sensitivity makes these galaxies key environments for testing CR transport models and refining our understanding of their role in galaxy evolution.

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arXiv2025

Prevention is better than cure? Feedback from high specific energy winds in cosmological simulations with Arkenstone

We deploy the new Arkenstone galactic wind model in cosmological simulations for the first time, allowing us to robustly resolve the evolution and impact of high specific energy winds. In a (25 $h^{-1}$ Mpc)$^3$ box we perform a set of numerical experiments that systematically vary the mass and energy loadings of such winds, finding that their energy content is the key parameter controlling the stellar to dark matter mass ratio. Increasing the mass loading, at fixed energy, actually results in mildly enhanced star formation, counter to prevailing wisdom, due to the wind becoming cooler. Of the simple parametrisations that we test, we find that an energy loading that scales inversely with halo mass best matches a wide range of observations and can do so with mass loadings drastically lower than those in most previous cosmological simulations. In this scenario, much less material is ejected from the interstellar medium. Instead, winds both heat gas in the circumgalactic medium, slowing infall onto the galaxy, and also drive shocks beyond the virial radius, decreasing the halo-scale accretion rate. We can also report that a much lower fraction of the available supernova energy is needed in preventative galaxy regulation than required by ejective wind feedback models such as IllustrisTNG. This is a Learning the Universe collaboration publication.

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arXiv2025

Protostellar disks in their natural habitat -- the formation of protostars and their accretion disks in the turbulent and magnetized interstellar medium

We present simulations of the supernova-driven turbulent interstellar medium (ISM) in a simulation domain of volume $(256\,{\rm pc})^3$ within which we resolve the formation of protostellar accretion disks and their stellar cores to spatial scales of $\sim 10^{-4}$ au, using the moving-mesh code {\small AREPO}. We perform simulations with no magnetic fields, ideal magnetohydrodynamics (MHD) and ambipolar diffusion, and compare the resulting first Larson cores and their associated structures, including the accretion disks, their location within the larger-scale structure and the streamers connecting these. We find that disks of sizes $10-100\,{\rm au}$ form early in the simulations without magnetic fields, while there are no disks larger than 10 au with ideal MHD. Ambipolar diffusion causes large disks to form in a subset of cases (two out of six cores), and generally reduces the strength of outflows, which are seen to play a central role. When they are able to carry away significant angular momentum, they prevent the formation of a rotationally supported disk. Magnetic fields strengths grow from $0.1 - 1$ mG in the protostellar core to more than 10 G in the first Larson core in all simulations with ideal MHD. The rotationally supported disks which form can have rotation speeds $> 1$ km s$^{-1}$ even out to further than 100 au from the centre, become gravitationally unstable and form complex spiral substructures with Toomre $Q < 1$. We conclude that the impact of magnetic fields and non-ideal MHD on the formation of protostellar disks is substantial in realistic formation scenarios from the turbulent ISM.

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arXiv2025

Accretion onto supermassive and intermediate mass black holes in cosmological simulations

Accretion is the dominant contribution to the cosmic massive black hole density in the Universe today. Yet, modelling it in cosmological simulations is challenging due to the dynamic range involved, as well as the theoretical uncertainties of the underlying mechanisms driving accretion from galactic to black hole horizon scales. We present a simple, flexible parametrization for gas inflows onto massive black holes in order to manage this uncertainty in large-volume cosmological simulations. This is done as part of the "Learning the Universe'' collaboration, which aims to jointly infer the initial conditions and physical processes governing the evolution of the Universe using a Bayesian forward-modelling approach. To allow such a forward-modelling, we update the prescription for accretion with a two-parameter free-fall based inflow estimate that allows for a radius-dependent inflow rate and add a simple model for unresolved accretion disks. We use uniform resolution cosmological hydrodynamical simulations and the IllustrisTNG framework to study the massive black hole population and its dependence on the introduced model parameters. Once the parameters of the accretion formula are chosen to result in a roughly similar redshift zero black hole mass density, the differences caused by the details in the accretion formula are moderate in the supermassive black hole regime, indicating that it is difficult to distinguish between accretion mechanisms based on luminous active galactic nuclei powered by supermassive black holes. Applying the same models to intermediate mass black holes at high redshift, however, reveals significantly different accretion rates in high redshift, moderate luminosity active galactic nuclei and different frequencies and mass distributions of intermediate mass black hole mergers for the same black hole formation model.

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arXiv2025

Ray-tracing Fast Radio Bursts Through IllustrisTNG: Cosmological Dispersion Measures from Redshift 0 to 5.5

The dispersion measures (DMs) of Fast Radio Bursts (FRBs) arise predominantly from free electrons in the large-scale structure of the Universe. The increasing number of FRB observations have started to empirically constrain the distribution of cosmic baryons, making it crucial to accurately forward model their propagation within cosmological simulations. In this work, we present a method for measuring FRB DMs in IllustrisTNG that continuously traces rays through the simulation while reconstructing all traversed line segments within the underlying Voronoi mesh. Leveraging this technique, we create over $20$ publicly available DM catalogs, including a full-sky DM map observed from a Milky Way-like environment. Our method addresses a problem in previous TNG-based studies, in which a sparse snapshot sampling in the path integral leads to a misestimation of the standard deviation and higher moments of the DM distribution $p(\rm{DM}|z)$ by over $50\%$. We show that our results are consistent with the most recent observational data from the DSA-110, ASKAP, and CHIME. We offer a functional form for $p(\rm{DM}| z)$ that provides very good fits across all redshifts from $0$ to $5.5$, showing that the previously proposed log-normal distribution is not well matched to the data. We find that using simulation box sizes smaller than $35\,h^{-1}\,$Mpc or resolutions with baryonic masses of less than $5\times10^{8}\,h^{-1}\,M_{\odot}$ can distort the derived DM signal by more than $8\%$. Our findings provide new insights into how the cosmic web shapes FRB signals, and highlight the importance of accurate methodology when comparing cosmological simulations against observations.

astro-ph.CO↗

arXiv2025

Cyclic Zoom: Multiscale GRMHD Modeling of Black Hole Accretion and Feedback

We present a ``cyclic zoom'' method to capture the dynamics of accretion flows onto black holes across a vast range of spatial and temporal scales in general relativistic magnetohydrodynamic (GRMHD) simulations. In this method, we cyclically zoom out (derefine) and zoom in (refine) the simulation domain while using a central mask region containing a careful treatment of the coarsened fluid variables to preserve the small-scale physics, in particular the magnetic field dynamics. The method can accelerate GRMHD simulations by $\gtrsim 10^5$ times for problems with large-scale separation. We demonstrate the validity of the technique using a series of tests, including spherically symmetric Bondi accretion, the Blandford-Znajek monopole, magnetized turbulent Bondi accretion, accretion of a magnetized rotating torus, and the long-term evolution of an accreting torus about both Schwarzschild and Kerr black holes. As applications, we simulate Bondi and rotating torus accretion onto black holes from galactic scales, covering an extremely large dynamic range. In Bondi accretion, the accretion rate is suppressed relative to the Bondi rate by $\sim(10r_\mathrm{g}/r_\mathrm{B})^{1/2}$ with a feedback power of $\sim 0.01 \dot{M} c^2$ for vanishing spin, and $\sim 0.1 \dot{M} c^2$ for spin $a\approx0.9$. In the long-term evolution of a rotating torus, the accretion rate decreases with time as $\dot{M}\propto t^{-2}$ on timescales much longer than the viscous timescale, demonstrating that our method can capture not only quasi-steady problems but also secular evolution. Our new method likewise holds significant promise for applications to many other problems that need to cover vast spatial and temporal scales.

astro-ph.HE↗

arXiv2025

Introducing the AIDA-TNG project: galaxy formation in alternative dark matter models

We introduce the AIDA-TNG project, a suite of cosmological magnetohydrodynamic simulations that simultaneously model galaxy formation and different variations of the underlying dark matter model. We consider the standard cold dark matter model and five variations, including three warm dark matter scenarios and two self-interacting models with constant or velocity-dependent cross-section. In each model, we simulate two cosmological boxes of 51.7 and 110.7 Mpc on a side, with the same initial conditions as TNG50 and TNG100, and combine the variations in the physics of dark matter with the fiducial IllustrisTNG galaxy formation model. The AIDA-TNG runs are thus ideal for studying the simultaneous effect of baryons and alternative dark matter models on observable properties of galaxies and large-scale structures. We resolve haloes in the range between $10^{8}$ and $4\times10^{14}\,$M$_{\odot}$ and scales down to the nominal resolution of 570 pc in the highest resolution runs. This work presents the first results on statistical quantities such as the halo mass function and the matter power spectrum; we quantify the modification in the number of haloes and the power on scales smaller than 1 Mpc, due to the combination of baryonic and dark matter physics. Despite being calibrated on cold dark matter, we find that the TNG galaxy formation model can produce a realistic galaxy population in all scenarios. The stellar and gas mass fraction, stellar mass function, black hole mass as a function of stellar mass and star formation rate density are very similar in all dark matter models, with some deviations only in the most extreme warm dark matter model. Finally, we also quantify changes in halo structure due to warm and self-interacting dark matter, which appear in the density profiles, concentration-mass relation and galaxy sizes.

astro-ph.CO↗

arXiv2025

Fully non-linear simulations of galaxy intrinsic alignments for weak lensing with the MillenniumTNG lightcone

We present a complete forward model of a realistic weak lensing galaxy catalogue based on the 740 Mpc hydrodynamical MillenniumTNG (MTNG) simulation. Starting with a complete particle and cell lightcone covering one octant of the sky with redshift range 0 < $z$ < 1.5, we apply a group and subhalo finder to generate the corresponding galaxy catalogue for a fiducial observer. For all galaxies, we compute both their intrinsic and lensing-induced shear. The intrinsic component is derived from the luminosity-weighted inertia tensor of stellar particles, while the extrinsic (gravitational) shear is obtained through full-sky ray-tracing on the same lightcone. This allows us to directly predict the impact of intrinsic alignment (IA) of galaxies on the shear correlation function and popular convergence statistics in a fully non-linear forward model. We find that IA modifies the convergence power spectrum at all angular scales by up to 20%, it significantly impacts the PDF, altering its tails by 10-20%, and distorts peak and minimum counts up to 30%, depending on redshift and scale. We also evaluate the impact of the IA signal on the shear correlation function finding that, along with a redshift dependence, the signal strongly increases for higher galaxy stellar mass cuts applied to the catalogue. Notably, with the highest stellar mass cut we apply, the intrinsic shear autocorrelation can become comparable to the gravitational shear component on small angular scales. Our results highlight the importance of accurately modeling IA for precision weak lensing cosmology with upcoming Stage IV surveys.

astro-ph.CO↗

arXiv2025

NOEMA$^{\rm 3D}$: A first kpc resolution study of a $z\sim1.5$ main sequence barred galaxy channeling gas into a growing bulge

We present a very deep CO(3-2) observation of a massive, gas-rich, main sequence, barred spiral galaxy at $z\approx1.52$. Our data were taken with the IRAM-NOEMA interferometer for a 12-antenna equivalent on-source integration time of $\sim$ 50 hours. We fit the major axis kinematics using forward modelling of a rotating disk, and then subtract the two-dimensional beam convolved best-fit model revealing signatures of planar non-circular motions in the residuals. The inferred in-plane radial velocities are remarkably large, of the order of $\approx60$ km/s. Direct comparisons with a high-resolution, simulated, gas-rich, barred galaxy, obtained with the moving mesh code AREPO and the TNG sub-grid model, show that the observed non-circular gas flows can be explained as radial flows driven by the central bar, with an inferred net inflow rate of the order of the SFR. Given the recent evidence for a higher-than-expected fraction of barred disk galaxies at cosmic noon, our results suggest that rapid gas inflows due to bars could be important evolutionary drivers for the dominant population of star-forming galaxies at the peak epoch of star and galaxy formation.

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arXiv2025

The mass accretion history of dark matter haloes down to Earth mass

We take advantage of the unprecedented dynamical range provided by the "Cosmic-Zoom" project to study the mass accretion history (MAH) of present-day dark matter haloes over the entire mass range present in the $Λ$CDM paradigm when the dark matter is made of weakly interacting massive particles of mass $100\ \mathrm{GeV}$. In particular, we complement previous studies by exploring the MAHs of haloes with mass from $10^8\ h^{-1}\mathrm{M_{\odot}}$ down to Earth mass, $10^{-6}\ h^{-1}\mathrm{M_{\odot}}$. The formation redshift of low-mass haloes anti-correlates weakly with mass, peaking at $z=3$ for haloes of mass $10^{-4}\ h^{-1}\mathrm{M_{\odot}}$. Even lower masses are affected by the free-streaming cutoff in the primordial spectrum of density fluctuations and form at lower redshift. We compare MAHs in our simulations with predictions from two analytical models based on the extended Press-Schechter theory (EPS), and three empirical models derived by fitting and extrapolating either results from cosmological $N$-body simulations or Monte Carlo realizations of halo growth. All models fit our simulations reasonably well over the mass range for which they were calibrated. While the empirical models match better for more massive haloes, $M>10^{10}\ h^{-1}\mathrm{M_{\odot}}$, the analytical models do better when extrapolated down to Earth mass. At the higher masses, we explore the correlation between local environment density and MAH, finding that biases are relatively weak, with typical MAHs for haloes in extremely low-density and in typical regions differing by less than $20$ percent at high redshift. If this result can be extrapolated to lower halo masses, we conclude that EPS theory predicts the hierarchical build-up of dark matter haloes quite well over the entire halo mass range.

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arXiv2025

Bar formation and evolution in the cosmological context: Inputs from the Auriga simulations

Galactic bars drive the internal evolution of spiral galaxies, while their formation is tightly coupled to the properties of their host galaxy and dark matter halo. To explore what drives bar formation in the cosmological context and how these structures evolve throughout cosmic history, we use the Auriga suite of magneto-hydrodynamical cosmological zoom-in simulations. We find that bars are robust and long-lived structures, and we recover a decreasing bar fraction with increasing redshift which plateaus around $\sim20\%$ at $z\sim3$. We find that bars which form at low and intermediate redshifts grow longer with time, while bars that form at high redshifts are born `saturated' in length, likely due to their merger-induced formation pathway. This leads to a larger bar-to-disc size ratio at high redshifts as compared to the local Universe. We subsequently examine the multi-dimensional parameter space thought to drive bar formation. We find that barred galaxies tend to have lower Toomre $Q$ values at the time of their formation, while we do not find a difference in the gas fraction of barred and unbarred populations when controlling for stellar mass. Barred galaxies tend to be more baryon-dominated at all redshifts and assemble their stellar mass earlier, while galaxies that are baryon-dominated but that do not host a bar, have a higher ex-situ bulge fraction. We explore the implications of the baryon-dominance of barred galaxies on the Tully-Fisher relation, finding an offset from the unbarred relation; confirming this in observations would serve as additional evidence for dark matter, as this behaviour is not readily explained in modified gravity scenarios.

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arXiv2025

Applying a star formation model calibrated on high-resolution interstellar medium simulations to cosmological simulations of galaxy formation

Modern high-resolution simulations of the interstellar medium (ISM) have shown that key factors in governing star formation are the competing influences of radiative dissipation, pressure support driven by stellar feedback, and the relentless pull of gravity. Cosmological simulations of galaxy formation, such as IllustrisTNG or ASTRID, are however not able to resolve this physics in detail and therefore need to rely on approximate treatments. These have often taken the form of empirical subgrid models of the ISM expressed in terms of an effective equation of state (EOS) that relates the mean ISM pressure to the mean gas density. Here we seek to improve these heuristic models by directly fitting their key ingredients to results of the high-resolution TIGRESS simulations, which have shown that the dynamical equilibrium of the ISM can be understood in terms of a pressure-regulated, feedback modulated (PRFM) model for star formation. Here we explore a simple subgrid model that draws on the PRFM concept but uses only local quantities. It accurately reproduces PRFM for pure gas disks, while it predicts slightly less star formation than PRFM in the presence of an additional thin stellar disk. We compare the properties of this model with the older Springel and Hernquist and TNG prescriptions, and apply all three to isolated simulations of disk galaxies as well as to a set of high-resolution zoom-in simulations carried out with a novel 'multi-zoom' technique that we introduce in this study. The softer EOS implied by TIGRESS produces substantially thinner disk galaxies, which has important ramifications for disk stability and galaxy morphology. The total stellar mass of galaxies is however hardly modified at low redshift, reflecting the dominating influence of large-scale gaseous inflows and outflows to galaxies, which are not sensitive to the EOS itself

astro-ph.GA↗

arXiv2025

Ray-tracing vs. Born approximation in full-sky weak lensing simulations of the MillenniumTNG project

Weak gravitational lensing is a powerful tool for precision tests of cosmology. As the expected deflection angles are small, predictions based on non-linear N-body simulations are commonly computed with the Born approximation. Here we examine this assumption using ${\small DORIAN}$, a newly developed full-sky ray-tracing scheme applied to high-resolution mass-shell outputs of the two largest simulations in the MillenniumTNG suite, each with a 3000 Mpc box containing almost 1.1 trillion cold dark matter particles in addition to 16.7 billion particles representing massive neutrinos. We examine simple two-point statistics like the angular power spectrum of the convergence field, as well as statistics sensitive to higher order correlations such as peak and minimum statistics, void statistics, and Minkowski functionals of the convergence maps. Overall, we find only small differences between the Born approximation and a full ray-tracing treatment. While these are negligibly small at power-spectrum level, some higher order statistics show more sizable effects; ray-tracing is necessary to achieve percent level precision. At the resolution reached here, full-sky maps with 0.8 billion pixels and an angular resolution of 0.43 arcmin, we find that interpolation accuracy can introduce appreciable errors in ray-tracing results. We therefore implemented an interpolation method based on nonuniform fast Fourier transforms (NUFFT) along with more traditional methods. Bilinear interpolation introduces significant smoothing, while nearest grid point sampling agrees well with NUFFT, at least for our fiducial source redshift, $z_s=1.0$, and for the 1 arcmin smoothing we use for higher-order statistics.

astro-ph.CO↗

arXiv2025

Pearls on a string: Dark and bright galaxies on a strikingly straight and narrow filament

We identify a chain of galaxies along an almost straight line in the nearby Universe with a projected length of ~5 Mpc. The galaxies are distributed within projected distances of only 7-105 kpc from the axis of the identified filament. They have redshifts in a very small range of z=0.0361-0.0370 so that their radial velocities are consistent with galaxy proper motions. The filament galaxies are mainly star-forming and have stellar masses in a range of $\rm 10^{9.1}-10^{10.7}\,M_{\odot}$. We search for systems with similar geometrical properties in the full-sky mock galaxy catalogue of the MillenniumTNG simulations and find that although such straight filaments are unusual and rare, they are predicted by $Λ$CDM simulations (4% incidence). We study the cold HI gas in a 1.3 Mpc section of the filament through HI-21cm emission line observations and detect eleven HI sources, many more than expected from the HI mass function in a similar volume. They have HI masses $\rm 10^{8.5}-10^{9.5}\,M_{\odot}$ and are mostly within ~120 kpc projected distance from the filament axis. None of these HI sources has a confirmed optical counterpart. Their darkness together with their large HI-21cm line-widths indicate that they contain gas that might not yet be virialized. These clouds must be marking the peaks of the dark matter and HI distributions over large scales within the filament. The presence of such gas clouds around the filament spines is predicted by simulations, but this is the first time that the existence of such clouds in a filament is observationally confirmed.

astro-ph.GA↗

arXiv2025

The impact of baryons on the internal structure of dark matter haloes from dwarf galaxies to superclusters in the redshift range 0<z<7

We investigate the redshift evolution of the concentration-mass relationship of dark matter haloes in state-of-the-art cosmological hydrodynamic simulations and their dark-matter-only counterparts. By combining the IllustrisTNG suite and the novel MillenniumTNG simulation, our analysis encompasses a wide range of box size ($50 - 740 \: \rm cMpc$) and mass resolution ($8.5 \times 10^4 - 3.1 \times 10^7 \: \rm M_{\odot}$ per baryonic mass element). This enables us to study the impact of baryons on the concentration-mass relationship in the redshift interval $0<z<7$ over an unprecedented halo mass range, extending from dwarf galaxies to superclusters ($\sim 10^{9.5}-10^{15.5} \, \rm M_{\odot}$). We find that the presence of baryons increases the steepness of the concentration-mass relationship at higher redshift, and demonstrate that this is driven by adiabatic contraction of the profile, due to gas accretion at early times, which promotes star formation in the inner regions of haloes. At lower redshift, when the effects of feedback start to become important, baryons decrease the concentration of haloes below the mass scale $\sim 10^{11.5} \, \rm M_{\odot}$. Through a rigorous information criterion test, we show that broken power-law models accurately represent the redshift evolution of the concentration-mass relationship, and of the relative difference in the total mass of haloes induced by the presence of baryons. We provide the best-fit parameters of our empirical formulae, enabling their application to models that mimic baryonic effects in dark-matter-only simulations over six decades in halo mass in the redshift range $0<z<7$.

astro-ph.CO↗

arXiv2025

Moving-mesh non-ideal magnetohydrodynamical simulations of the collapse of cloud cores to protostars

Magnetic fields have been shown both observationally and through theoretical work to be an important factor in the formation of protostars and their accretion disks. Accurate modelling of the evolution of the magnetic field in low-ionization molecular cloud cores requires the inclusion of non-ideal magnetohydrodynamics (MHD) processes, specifically Ohmic and ambipolar diffusion and the Hall effect. These have a profound influence on the efficiency of magnetic removal of angular momentum from protostellar disks and simulations that include them can avoid the `magnetic-braking catastrophe' in which disks are not able to form. However, the impact of the Hall effect, in particular, is complex and remains poorly studied. In this work, we perform a large suite of simulations of the collapse of cloud cores to protostars with several non-ideal MHD chemistry models and initial core geometries using the moving-mesh code {\small AREPO}. We find that the efficiency of angular momentum removal is significantly reduced with respect to ideal MHD, in line with previous results. The Hall effect has a varied influence on the evolution of the disk which depends on the initial orientation of the magnetic field. This extends to the outflows seen in a subset of the models, where this effect can act to enhance or suppress them and open up new outflow channels. We conclude, in agreement with a subset of the previous literature, that the Hall effect is the dominant non-ideal MHD process in some collapse scenarios and thus should be included in simulations of protostellar disk formation.

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arXiv2024

Probing galaxy evolution from $z=0$ to $z\simeq10$ through galaxy scaling relations in three L-Galaxies flavours

We present a comprehensive examination of the three latest versions of the L-Galaxies semi-analytic galaxy formation model, focusing on the evolution of galaxy properties across a broad stellar mass range ($10^7\:{\rm M}_{\odot}\lesssim{M_\star}\lesssim10^{12}\:{\rm M}_{\odot}$) from $z=0$ to $z\simeq10$. This study is the first to compare predictions of L-Galaxies with high-redshift observations well outside the original calibration regime, utilising multiband data from surveys such as SDSS, CANDELS, COSMOS, HST, JWST, and ALMA. We assess the models' ability to reproduce various time-dependent galaxy scaling relations for star-forming and quenched galaxies. Key focus areas include global galaxy properties such as stellar mass functions, cosmic star formation rate density, and the evolution of the main sequence of star-forming galaxies. Additionally, we examine resolved morphological properties such as the galaxy mass-size relation, alongside core $(R<1\,{\rm{kpc}})$ and effective $(R<R_{\rm{e}})$ stellar-mass surface densities as a function of stellar mass. This analysis reveals that the L-Galaxies models are in qualitatively good agreement with observed global scaling relations up to $z\simeq10$. However, significant discrepancies exist at both low and high redshifts in accurately reproducing the number density, size, and surface density evolution of quenched galaxies. These issues are most pronounced for massive central galaxies, where the simulations underpredict the abundance of quenched systems at $z\geq1.5$, reaching a discrepancy of a factor of 60 by $z\approx3$, with sizes several times larger than observed. Therefore, we propose that the physical prescriptions governing galaxy quenching, such as AGN feedback and processes related to merging, require improvement to be more consistent with observational data.

astro-ph.GA↗

arXiv2024

The Millennium and Astrid galaxies in effective field theory: comparison with galaxy-halo connection models at the field level

Cosmological analyses of redshift space clustering data are primarily based on using luminous ``red'' galaxies (LRGs) and ``blue'' emission line galaxies (ELGs) to trace underlying dark matter. Using the large high-fidelity high-resolution MillenniumTNG (MTNG) and Astrid simulations, we study these galaxies with the effective field theory (EFT)-based field level forward model. We confirm that both red and blue galaxies can be accurately modeled with EFT at the field level and their parameters match those of the phenomenological halo-based models. Specifically, we consider the state of the art Halo Occupation Distribution (HOD) and High Mass Quenched (HMQ) models for the red and blue galaxies, respectively. Our results explicitly confirm the validity of the halo-based models on large scales beyond the two-point statistics. In addition, we validate the field-level HOD/HMQ-based priors for EFT full-shape analysis. We find that the local bias parameters of the ELGs are in tension with the predictions of the LRG-like HOD models and present a simple analytic argument explaining this phenomenology. We also confirm that ELGs exhibit weaker non-linear redshift-space distortions (``fingers-of-God''), suggesting that a significant fraction of their data should be perturbative. We find that the response of EFT parameters to galaxy selection is sensitive to assumptions about baryonic feedback, suggesting that a detailed understanding of feedback processes is necessary for robust predictions of EFT parameters. Finally, using neural density estimation based on paired HOD-EFT parameter samples, we obtain optimal HOD models that reproduce the clustering of Astrid and MTNG galaxies.

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