arXiv subjects

Debora Sijacki

Publications and source records attributed to Debora Sijacki.

At least 109 records · Page 6Linked to original sources

arXiv2015

Feedback from Active Galactic Nuclei: Energy- versus momentum-driving

We employ hydrodynamical simulations using the moving-mesh code AREPO to investigate the role of energy and momentum input from Active Galactic Nuclei (AGN) in driving large-scale galactic outflows. We start by reproducing analytic solutions for both energy- and momentum-driven outflowing shells in simulations of a spherical isolated dark matter potential with gas in hydrostatic equilibrium and with no radiative cooling. We confirm that for this simplified setup, galactic outflows driven by a momentum input rate of order L_Edd/c can establish an M_BH - sigma relation with slope and normalisation similar to that observed. We show that momentum input at a rate of L_Edd/c is however insufficient to drive efficient outflows once cooling and gas inflows as predicted by cosmological simulations at resolved scales are taken into account. We argue that observed large-scale AGN-driven outflows are instead likely to be energy-driven and show that such outflows can reach momentum fluxes exceeding 10 L_Edd/c within the innermost 10 kpc of the galaxy. The outflows are highly anisotropic, with outflow rates and a velocity structure found to be inadequately described by spherical outflow models. We verify that the hot energy-driven outflowing gas is expected to be strongly affected by metal-line cooling, leading to significant amounts (>10^9 M_sun) of entrained cold gas.

astro-ph.GA↗

arXiv2015

Fast cold gas in hot AGN outflows

Observations of the emission from spatially extended cold gas around bright high-redshift QSOs reveal surprisingly large velocity widths exceeding 2000 km s^(-1), out to projected distances as large as 30 kpc. The high velocity widths have been interpreted as the signature of powerful AGN-driven outflows. Naively, these findings appear in tension with hydrodynamic models in which AGN-driven outflows are energy-driven and thus very hot with typical temperatures T = 10^6-7 K. Using the moving-mesh code Arepo, we perform 'zoom-in' cosmological simulations of a z = 6 QSO and its environment, following black hole growth and feedback via energy-driven outflows. In the simulations, the QSO host galaxy is surrounded by a clumpy circum-galactic medium pre-enriched with metals due to supernovae-driven galactic outflows. As a result, part of the AGN-driven hot outflowing gas can cool radiatively, leading to large amounts (> 10^9 M_sun) of cold gas comoving with the hot bipolar outflow. This results in velocity widths of spatially extended cold gas similar to those observed. We caution, however, that gas inflows, random motions in the deep potential well of the QSO host galaxy and cooling of supernovae-driven winds contribute significantly to the large velocity width of the cold gas in the simulations, complicating the interpretation of observational data.

astro-ph.GA↗

arXiv2015

The Impact of Galactic Feedback on the Circumgalactic Medium

Galactic feedback strongly affects the way galactic environments are enriched. We examine this connection by performing a suite of cosmological hydrodynamic simulations, exploring a range of parameters based on the galaxy formation model developed in Vogelsberger et al. 2013 (henceforth V13). We examine the effects of AGN feedback, wind mass loading, wind specific energy, and wind metal-loading on the properties of the circumgalactic medium (CGM) of galaxies with $M_\text{halo} > 10^{11} M_\odot$. Note that while the V13 model was tuned to match observations including the stellar mass function, no explicit tuning was done for the CGM. The wind energy per unit outflow mass has the most significant effect on the CGM enrichment. High energy winds launch metals far beyond the virial radius. AGN feedback also has a significant effect, but only at $z < 3$. We compare to high redshift HI and CIV observations. All our simulations produce the observed number of Damped Lyman-$α$ Absorbers. At lower column density, several of our simulations produce enough Lyman Limit Systems (LLS) $100$ kpc from the galaxy, but in all cases the LLS abundance falls off with distance faster than observations, with too few LLS at $200$ kpc. Further, in all models the CIV abundance drops off too sharply with distance, with too little CIV $100$-$200$ kpc from the galaxy. Higher energy wind models produce more extended CIV but also produce less stars, in tension with star-formation rate density observations. This highlights the fact that circumgalactic observations are a strong constraint on galactic feedback models.

astro-ph.GA↗

arXiv2014

The star formation main sequence and stellar mass assembly of galaxies in the Illustris simulation

Understanding the physical processes that drive star formation is a key challenge for galaxy formation models. In this article we study the tight correlation between the star formation rate (SFR) and stellar mass of galaxies at a given redshift, how halo growth influences star formation, and star formation histories of individual galaxies. We study these topics using Illustris, a state-of-the-art cosmological hydrodynamical simulation of galaxy formation. Illustris reproduces the observed relation (the star formation main sequence; SFMS) between SFR and stellar mass at redshifts z=0 and z=4, but at intermediate redshifts of z~2, the simulated SFMS has a significantly lower normalisation than reported by observations. The scatter in the relation is consistent with the observed scatter. However, the fraction of outliers above the SFR-stellar mass relation in Illustris is less than that observed. Galaxies with halo masses of ~10^{12} solar masses dominate the SFR density of the Universe, in agreement with the results of abundance matching. Furthermore, more-massive galaxies tend to form the bulk of their stars at high redshift, which indicates that `downsizing' occurs in Illustris. We also studied the star formation histories of individual galaxies, including the use of a principal component analysis decomposition. We find that for fixed stellar mass, galaxies that form earlier have more-massive black holes at z=0, indicating that star formation and black hole growth are tightly linked processes in Illustris. While many of the properties of normal star-forming galaxies are well-reproduced in the Illustris simulation, forming a realistic population of starbursts will likely require higher resolution and probably a more sophisticated treatment of star formation and feedback from stars and black holes.

astro-ph.GA↗

arXiv2014

Synthetic Galaxy Images and Spectra from the Illustris Simulation

We present our methods for generating a catalog of 7,000 synthetic images and 40,000 integrated spectra of redshift z = 0 galaxies from the Illustris Simulation. The mock data products are produced by using stellar population synthesis models to assign spectral energy distributions (SED) to each star particle in the galaxies. The resulting synthetic images and integrated SEDs therefore properly reflect the spatial distribution, stellar metallicity distribution, and star formation history of the galaxies. From the synthetic data products it is possible to produce monochromatic or color-composite images, perform SED fitting, classify morphology, determine galaxy structural properties, and evaluate the impacts of galaxy viewing angle. The main contribution of this paper is to describe the production, format, and composition of the image catalog that makes up the Illustris Simulation Obsevatory. As a demonstration of this resource, we derive galactic stellar mass estimates by applying the SED fitting code FAST to the synthetic galaxy products, and compare the derived stellar masses against the true stellar masses from the simulation. We find from this idealized experiment that systematic biases exist in the photometrically derived stellar mass values that can be reduced by using a fixed metallicity in conjunction with a minimum galaxy age restriction.

astro-ph.GA↗

arXiv2014

The colors of satellite galaxies in the Illustris Simulation

Observationally, the fraction of blue satellite galaxies decreases steeply with host halo mass, and their radial distribution around central galaxies is significantly shallower in massive (M_* >10e11M_sun) than in Milky Way like systems. Theoretical models, based primarily on semi-analytical techniques, have had a long-standing problem with reproducing these trends, instead predicting too few blue satellites in general but also estimating a radial distribution that is too shallow, regardless of primary mass. In this Letter, we use the Illustris cosmological simulation to study the properties of satellite galaxies around isolated primaries. For the first time, we find good agreement between theory and observations. We identify the main source of this success relative to earlier work to be a consequence of the large gas contents of satellites at infall, a factor ~5-10 times larger than in semi-analytical models. Because of their relatively large gas reservoirs, satellites can continue to form stars long after infall, with a typical timescale for star-formation to be quenched ~2 Gyr in groups but more than ~5 Gyr for satellites around Milky Way like primaries. The gas contents we infer are consistent with z=0 observations of HI gas in galaxies, although we find large discrepancies among reported values in the literature. A testable prediction of our model is that the gas-to-stellar mass ratio of satellite progenitors should vary only weakly with cosmic time.

astro-ph.GA↗

arXiv2014

Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe

We introduce the Illustris Project, a series of large-scale hydrodynamical simulations of galaxy formation. The highest resolution simulation, Illustris-1, covers a volume of $(106.5\,{\rm Mpc})^3$, has a dark mass resolution of ${6.26 \times 10^{6}\,{\rm M}_\odot}$, and an initial baryonic matter mass resolution of ${1.26 \times 10^{6}\,{\rm M}_\odot}$. At $z=0$ gravitational forces are softened on scales of $710\,{\rm pc}$, and the smallest hydrodynamical gas cells have an extent of $48\,{\rm pc}$. We follow the dynamical evolution of $2\times 1820^3$ resolution elements and in addition passively evolve $1820^3$ Monte Carlo tracer particles reaching a total particle count of more than $18$ billion. The galaxy formation model includes: primordial and metal-line cooling with self-shielding corrections, stellar evolution, stellar feedback, gas recycling, chemical enrichment, supermassive black hole growth, and feedback from active galactic nuclei. At $z=0$ our simulation volume contains about $40,000$ well-resolved galaxies covering a diverse range of morphologies and colours including early-type, late-type and irregular galaxies. The simulation reproduces reasonably well the cosmic star formation rate density, the galaxy luminosity function, and baryon conversion efficiency at $z=0$. It also qualitatively captures the impact of galaxy environment on the red fractions of galaxies. The internal velocity structure of selected well-resolved disk galaxies obeys the stellar and baryonic Tully-Fisher relation together with flat circular velocity curves. In the well-resolved regime the simulation reproduces the observed mix of early-type and late-type galaxies. Our model predicts a halo mass dependent impact of baryonic effects on the halo mass function and the masses of haloes caused by feedback from supernova and active galactic nuclei.

astro-ph.CO↗

arXiv2014

Damped Lyman-alpha absorbers as a probe of stellar feedback

We examine the abundance, clustering and metallicity of Damped Lyman-alpha Absorbers (DLAs) in a suite of hydrodynamic cosmological simulations using the moving mesh code AREPO. We incorporate models of supernova and AGN feedback, as well as molecular hydrogen formation. We compare our simulations to the column density distribution function at $z=3$, the total DLA abundance at $z=2-4$, the measured DLA bias at $z=2.3$ and the DLA metallicity distribution at $z=2-4$. Our preferred models produce populations of DLAs in good agreement with most of these observations. The exception is the DLA abundance at $z < 3$, which we show requires stronger feedback in $10^{11-12} \, h^{-1} M_\odot$ mass halos. While the DLA population probes a wide range of halo masses, we find the cross-section is dominated by halos of mass $10^{10} - 10^{11} \, h^{-1} M_\odot$ and virial velocities $50 - 100 \;\mathrm{km/s}$. The simulated DLA population has a linear theory bias of $1.7$, whereas the observations require $2.17 \pm 0.2$. We show that non-linear growth increases the bias in our simulations to $2.3$ at $k=1\; \mathrm{Mpc/}h$, the smallest scale observed. The scale-dependence of the bias is, however, very different in the simulations compared against the observations. We show that, of the observations we consider, the DLA abundance and column density function provide the strongest constraints on the feedback model.

astro-ph.CO↗

arXiv2014

Halo Mass and Assembly History Exposed in the Faint Outskirts: the Stellar and Dark Matter Haloes of Illustris Galaxies

We use the Illustris Simulations to gain insight into the build-up of the outer, low-surface brightness regions which surround galaxies. We characterize the stellar haloes by means of the logarithmic slope of the spherically-averaged stellar density profiles, alphaSTARS at z=0, and we relate these slopes to the properties of the underlying Dark-Matter (DM) haloes, their central galaxies, and their assembly histories. We analyze a sample of ~5,000 galaxies resolved with more than 5x10^4 particles each, and spanning a variety of morphologies and halo masses (3x10^11 < Mvir < 10^14 Msun). We find a strong trend between stellar halo slope and total halo mass, where more massive objects have shallower stellar haloes than the less massive ones (-5.5 \pm 0.5 < alphaSTARS <-3.5 \pm 0.2 in the studied mass range). At fixed halo mass, we show that disk-like, blue, young, and more massive galaxies are surrounded by significantly steeper stellar haloes than elliptical, red, older, and less massive galaxies. Overall, the stellar density profiles fall off much more steeply than the underlying DM, and no clear trend holds between stellar slope and DM halo concentration. However, DM haloes which formed more recently, or which accreted larger fractions of stellar mass from infalling satellites, exhibit shallower stellar haloes than their older analogs with similar masses, by up to Delta(alphaSTARS) ~ 0.5-0.7. Our findings, combined with the most recent measurements of the strikingly different stellar power-law indexes for M31 and the Milky Way, appear to favour a massive M31, and a Milky Way characterized by a much quieter accretion history over the past 10 Gyrs than its companion.

astro-ph.GA↗

arXiv2014

Introducing the Illustris Project: the evolution of galaxy populations across cosmic time

We present an overview of galaxy evolution across cosmic time in the Illustris Simulation. Illustris is an N-body/hydrodynamical simulation that evolves 2*1820^3 resolution elements in a (106.5Mpc)^3 box from cosmological initial conditions down to z=0 using the AREPO moving-mesh code. The simulation uses a state-of-the-art set of physical models for galaxy formation that was tuned to reproduce the z=0 stellar mass function and the history of the cosmic star-formation rate density. We find that Illustris successfully reproduces a plethora of observations of galaxy populations at various redshifts, for which no tuning was performed, and provide predictions for future observations. In particular, we discuss (a) the buildup of galactic mass, showing stellar mass functions and the relations between stellar mass and halo mass from z=7 to z=0, (b) galaxy number density profiles around massive central galaxies out to z=4, (c) the gas and total baryon content of both galaxies and their halos for different redshifts, and as a function of mass and radius, and (d) the evolution of galaxy specific star-formation rates up to z=8. In addition, we (i) present a qualitative analysis of galaxy morphologies from z=5 to z=0, for the stellar as well as the gaseous components, and their appearance in HST mock observations, (ii) follow galaxies selected at z=2 to their z=0 descendants, and quantify their growth and merger histories, and (iii) track massive z=0 galaxies to high redshift and study their joint evolution in star-formation activity and compactness. We conclude with a discussion of several disagreements with observations, and lay out possible directions for future research.

astro-ph.CO↗

arXiv2014

Properties of galaxies reproduced by a hydrodynamic simulation

Previous simulations of the growth of cosmic structures have broadly reproduced the 'cosmic web' of galaxies that we see in the Universe, but failed to create a mixed population of elliptical and spiral galaxies due to numerical inaccuracies and incomplete physical models. Moreover, because of computational constraints, they were unable to track the small scale evolution of gas and stars to the present epoch within a representative portion of the Universe. Here we report a simulation that starts 12 million years after the Big Bang, and traces 13 billion years of cosmic evolution with 12 billion resolution elements in a volume of $(106.5\,{\rm Mpc})^3$. It yields a reasonable population of ellipticals and spirals, reproduces the distribution of galaxies in clusters and statistics of hydrogen on large scales, and at the same time the metal and hydrogen content of galaxies on small scales.

astro-ph.CO↗

arXiv2014

Complexity Phenomena and ROMA of the Magnetospheric Cusp, Hydrodynamic Turbulence, and the Cosmic Web

Dynamic Complexity is a phenomenon exhibited by a nonlinearly interacting system within which multitudes of different sizes of large scale coherent structures emerge, resulting in a globally nonlinear stochastic behavior vastly different from that could be surmised from the underlying equations of interaction. The hallmark of such nonlinear, complex phenomena is the appearance of intermittent fluctuating events with the mixing and distributions of correlated structures at all scales. We briefly review here a relatively recent method, ROMA (rank-ordered multifractal analysis), explicitly constructed to analyze the intricate details of the distribution and scaling of such types of intermittent structures. This method is then applied to the analyses of selected examples related to the dynamical plasmas of the cusp region of the magnetosphere, velocity fluctuations of classical hydrodynamic turbulence, and the distribution of the structures of the cosmic gas obtained through large scale, moving mesh simulations. Differences and similarities of the analyzed results among these complex systems will be contrasted and highlighted. The first two examples have direct relevance to the geospace environment and are summaries of previously reported findings. The third example on the cosmic gas, though involving phenomena much larger in spatiotemporal scales, with its highly compressible turbulent behavior and the unique simulation technique employed in generating the data, provides direct motivations of applying such analysis to studies of similar multifractal processes in various extreme environments. These new results are both exciting and intriguing.

astro-ph.CO↗

arXiv2013

A model for cosmological simulations of galaxy formation physics

We present a new comprehensive model of the physics of galaxy formation designed for large-scale hydrodynamical simulations of structure formation using the moving mesh code AREPO. Our model includes primordial and metal line cooling with self-shielding corrections, stellar evolution and feedback processes, gas recycling, chemical enrichment, a novel subgrid model for the metal loading of outflows, black hole (BH) seeding, BH growth and merging procedures, quasar- and radio-mode feedback, and a prescription for radiative electro-magnetic (EM) feedback from active galactic nuclei (AGN). The metal mass loading of outflows can be adjusted independently of the wind mass loading. This is required to simultaneously reproduce the stellar mass content of low mass haloes and their gas oxygen abundances. Radiative EM AGN feedback is implemented assuming an average spectral energy distribution and a luminosity-dependent scaling of obscuration effects. This form of feedback suppresses star formation more efficiently than continuous thermal quasar-mode feedback alone, but is less efficient than mechanical radio-mode feedback in regulating star formation in massive haloes. We contrast simulation predictions for different variants of our galaxy formation model with key observations. Our best match model reproduces, among other things, the cosmic star formation history, the stellar mass function, the stellar mass - halo mass relation, g-, r-, i-, z-band SDSS galaxy luminosity functions, and the Tully-Fisher relation. We can achieve this success only if we invoke very strong forms of stellar and AGN feedback such that star formation is adequately reduced in both low and high mass systems. In particular, the strength of radio-mode feedback needs to be increased significantly compared to previous studies to suppress efficient cooling in massive, metal-enriched haloes.

astro-ph.CO↗

arXiv2013

Following the flow: tracer particles in astrophysical fluid simulations

We present two numerical schemes for passive tracer particles in the hydrodynamical moving-mesh code AREPO, and compare their performance for various problems, from simple setups to cosmological simulations. The purpose of tracer particles is to allow the flow to be followed in a Lagrangian way, tracing the evolution of the fluid with time, and allowing the thermodynamical history of individual fluid parcels to be recorded. We find that the commonly-used `velocity field tracers', which are advected using the fluid velocity field, do not in general follow the mass flow correctly, and explain why this is the case. This method can result in orders-of-magnitude biases in simulations of driven turbulence and in cosmological simulations, rendering the velocity field tracers inappropriate for following these flows. We then discuss a novel implementation of `Monte Carlo tracers', which are moved along with fluid cells, and are exchanged probabilistically between them following the mass flux. This method reproduces the mass distribution of the fluid correctly. The main limitation of this approach is that it is more diffusive than the fluid itself. Nonetheless, we show that this novel approach is more reliable than what has been employed previously and demonstrate that it is appropriate for following hydrodynamical flows in mesh-based codes. The Monte Carlo tracers can also naturally be transferred between fluid cells and other types of particles, such as stellar particles, so that the mass flow in cosmological simulations can be followed in its entirety.

astro-ph.IM↗

arXiv2013

Hot X-ray coronae around massive spiral galaxies: a unique probe of structure formation models

Luminous X-ray gas coronae in the dark matter halos of massive spiral galaxies are a fundamental prediction of structure formation models, yet only a few such coronae have been detected so far. In this paper, we study the hot X-ray coronae beyond the optical disks of two normal massive spirals, NGC1961 and NGC6753. Based on XMM-Newton X-ray observations, hot gaseous emission is detected to ~60 kpc - well beyond their optical radii. The hot gas has a best-fit temperature of kT~0.6 keV and an abundance of ~0.1 Solar, and exhibits a fairly uniform distribution, suggesting that the quasi-static gas resides in hydrostatic equilibrium in the potential well of the galaxies. The bolometric luminosity of the gas in the (0.05-0.15)r_200 region (r_200 is the virial radius) is ~6e40 erg/s for both galaxies. The baryon mass fractions of NGC1961 and NGC6753 are f_b~0.1, which fall short of the cosmic baryon fraction. The hot coronae around NGC1961 and NGC6753 offer an excellent basis to probe structure formation simulations. To this end, the observations are confronted with the moving mesh code Arepo and the smoothed particle hydrodynamics code Gadget. Although neither model gives a perfect description, the observed luminosities, gas masses, and abundances favor the Arepo code. Moreover, the shape and the normalization of the observed density profiles are better reproduced by Arepo within ~0.5r_200. However, neither model incorporates efficient feedback from supermassive black holes or supernovae, which could alter the simulated properties of the X-ray coronae. With the further advance of numerical models, the present observations will be essential in constraining the feedback effects in structure formation simulations.

astro-ph.CO↗

arXiv2013

A discontinuous Galerkin method for solving the fluid and MHD equations in astrophysical simulations

A discontinuous Galerkin (DG) method suitable for large-scale astrophysical simulations on Cartesian meshes as well as arbitrary static and moving Voronoi meshes is presented. Most major astrophysical fluid dynamics codes use a finite volume (FV) approach. We demonstrate that the DG technique offers distinct advantages over FV formulations on both static and moving meshes. The DG method is also easily generalized to higher than second-order accuracy without requiring the use of extended stencils to estimate derivatives (thereby making the scheme highly parallelizable). We implement the technique in the AREPO code for solving the fluid and the magnetohydrodynamic (MHD) equations. By examining various test problems, we show that our new formulation provides improved accuracy over FV approaches of the same order, and reduces post-shock oscillations and artificial diffusion of angular momentum. In addition, the DG method makes it possible to represent magnetic fields in a locally divergence-free way, improving the stability of MHD simulations and moderating global divergence errors, and is a viable alternative for solving the MHD equations on meshes where Constrained-Transport (CT) cannot be applied. We find that the DG procedure on a moving mesh is more sensitive to the choice of slope limiter than is its FV method counterpart. Therefore, future work to improve the performance of the DG scheme even further will likely involve the design of optimal slope limiters. As presently constructed, our technique offers the potential of improved accuracy in astrophysical simulations using the moving mesh AREPO code as well as those employing adaptive mesh refinement (AMR).

physics.comp-ph↗

arXiv2013

A physical model for cosmological simulations of galaxy formation: multi-epoch validation

We present a multi-epoch analysis of the galaxy populations formed within the cosmological hydrodynamical simulations presented in Vogelsberger et al. (2013). These simulations explore the performance of a recently implemented feedback model which includes primordial and metal line radiative cooling with self-shielding corrections; stellar evolution with associated mass loss and chemical enrichment; feedback by stellar winds; black hole seeding, growth and merging; and AGN quasar- and radio-mode heating with a phenomenological prescription for AGN electro-magnetic feedback. We illustrate the impact of the model parameter choices on the resulting simulated galaxy population properties at high and intermediate redshifts. We demonstrate that our scheme is capable of producing galaxy populations that broadly reproduce the observed galaxy stellar mass function extending from redshift z=0 to z=3. We also characterise the evolving galactic B-band luminosity function, stellar mass to halo mass ratio, star formation main sequence, Tully-Fisher relation, and gas-phase mass-metallicity relation and confront them against recent observational estimates. This detailed comparison allows us to validate elements of our feedback model, while also identifying areas of tension that will be addressed in future work.

astro-ph.CO↗

arXiv2013

Moving mesh cosmology: tracing cosmological gas accretion

We investigate the nature of gas accretion onto haloes and galaxies at z=2 using cosmological hydrodynamic simulations run with the moving mesh code AREPO. Implementing a Monte Carlo tracer particle scheme to determine the origin and thermodynamic history of accreting gas, we make quantitative comparisons to an otherwise identical simulation run with the smoothed particle hydrodynamics (SPH) code GADGET-3. Contrasting these two numerical approaches, we find significant physical differences in the thermodynamic history of accreted gas in haloes above 10^10.5 solar masses. In agreement with previous work, GADGET simulations show a cold fraction near unity for galaxies forming in massive haloes, implying that only a small percentage of accreted gas heats to an appreciable fraction of the virial temperature during accretion. The same galaxies in AREPO show a much lower cold fraction, <20% in haloes above 10^11 solar masses. This results from a hot gas accretion rate which, at this same halo mass, is an order of magnitude larger than with GADGET, while the cold accretion rate is also lower. These discrepancies increase for more massive systems, and we explain both as due to numerical inaccuracies in the standard formulation of SPH. We also observe that the relatively sharp transition from cold to hot mode dominated accretion, at a halo mass of ~10^11, is a consequence of comparing past gas temperatures to a constant threshold value independent of virial temperature. Examining the spatial distribution of accreting gas, we find that gas filaments in GADGET tend to remain collimated and flow coherently to small radii, or artificially fragment and form a large number of purely numerical "blobs". Similar gas streams in AREPO show increased heating and disruption at 0.25-0.5 virial radii and contribute to the hot gas accretion rate in a manner distinct from classical cooling flows.

astro-ph.CO↗