The cold dark matter paradigm describes the large-scale structure of Universe remarkably well. However, there exists some tension with observed abundances and internal density structures both field dwarf galaxies galactic satellites. Here, we demonstrate that a simple class models may offer viable solution to all these problems simultaneously. Their key phenomenological properties are velocity-dependent self-interactions mediated by light vector messenger thermal production much later...

Inverse Compton cascades (ICCs) initiated by energetic gamma rays (E ≳ 100 GeV) enhance the GeV emission from bright, extragalactic TeV sources. The absence of this bright blazars has been used to constrain intergalactic magnetic field (IGMF), and stringent limits placed on unresolved gamma-ray background (EGRB) Fermi have argue against a large number such objects at high redshifts. However, these are predicated assumption that inverse scattering is primary energy-loss mechanism for...

We present the first simulations within an effective theory of structure formation (ETHOS), which includes effect interactions between dark matter and radiation on linear initial power spectrum self-interactions during non-linear formation. simulate a Milky Way-like halo in four different models cold case. Our highest resolution simulation has particle mass $2.8\times 10^4\,{\rm M}_\odot$ softening length $72.4\,{\rm pc}$. demonstrate that all alternative have only negligible impact large...

We formulate an effective theory of structure formation (ETHOS) that enables cosmological to be computed in almost any microphysical model dark matter physics. This framework maps the detailed theories particle interactions into physical parameters shape linear power spectrum and self-interaction transfer cross section non-relativistic matter. These are input simulations, which follow evolution galactic distributions. Models with similar ETHOS but different physics would nevertheless result...

We wish to constrain the cosmic-ray proton (CRp) population in galaxy clusters. By hadronic interactions with thermal gas of intra-cluster medium (ICM), CRp produce γ-rays for which we develop an analytic formalism deduce their spectral distribution. Assuming CRp-to-thermal energy density ratio and index be spatially constant, derive relation between γ-ray bolometric X-ray fluxes, . Based on our relation, compile a sample suitable clusters are promising candidates future detection resulting...

We develop a formalism for the identification and accurate estimation of strength structure formation shocks during cosmological smoothed particle hydrodynamics simulations. Shocks not only play decisive role thermalization gas in virialising structures but also acceleration relativistic cosmic rays (CRs) through diffusive shock acceleration. Our is applicable both to ordinary non-relativistic thermal gas, plasmas composed CRs gas. To this end, we derive an analytical solution...

Galactic winds are observed in many spiral galaxies with sizes from dwarfs up to the Milky Way, and they sometimes carry a mass excess of that newly formed stars by factor ten. Multiple driving processes such have been proposed, including thermal pressure due supernova-heating, UV radiation on dust grains, or cosmic ray (CR) pressure. We here study wind formation CR physics using numerical model accounts for acceleration supernovae, thermalization, advective transport. In addition, we...

Secondary anisotropies in the cosmic microwave background are a treasure-trove of cosmological information. Interpreting current experiments probing them limited by theoretical uncertainties rather than measurement errors. Here we focus on secondary resulting from thermal Sunyaev–Zel'dovich (tSZ) effect; amplitude which depends critically average pressure profile galaxy groups and clusters. To this end, use suite hydrodynamical TreePM-SPH simulations that include radiative cooling, star...

We explore how radiative cooling, supernova feedback, cosmic rays, and a new model of the energetic feedback from active galactic nuclei (AGNs) affect thermal kinetic Sunyaev–Zel'dovich (SZ) power spectra. To do this, we use suite hydrodynamical TreePM-SPH simulations web in large periodic boxes tailored higher resolution individual galaxy clusters. Our AGN match recent universal pressure profile cluster mass scaling relations REXCESS X-ray sample better than previous analytical or numerical...

It is well known that cosmic rays contribute significantly to the pressure of interstellar medium in our own Galaxy, suggesting they may play an important role regulating star formation during and evolution galaxies. We here discuss a novel numerical treatment physics its implementation parallel smoothed particle hydrodynamics code GADGET-2. In methodology, non-thermal ray population each gaseous fluid element approximated by simple power law spectrum momentum, characterized amplitude,...

The utility of large Sunyaev–Zel'dovich (SZ) surveys for determining cosmological parameters from cluster abundances is limited by the theoretical uncertainties in integrated SZ–flux-to-mass relation, Y–M. We explore how non-thermal pressure and anisotropic shape gas distribution intracluster medium (ICM) impacts Y–M scaling using a suite smoothed particle hydrodynamic simulations cosmic web. contrast results models with different treatments entropy injection transport, varying radiative...

High-resolution X-ray observations have revealed cavities and "cold fronts" with sharp edges in temperature density within galaxy clusters. Their presence poses a puzzle, since these features are not expected to be hydrodynamically stable or remain the of diffusion. However, moving core bubble even very weakly magnetized plasma necessarily sweeps up enough magnetic field build dynamically important sheath; layer's strength is set by competition between "plowing up" slipping around lines,...

We discuss new methods to integrate the cosmic ray (CR) evolution equations coupled magnetohydrodynamics on an unstructured moving mesh, as realized in massively parallel arepo code for cosmological simulations. account diffusive shock acceleration of CRs at resolved shocks and supernova remnants interstellar medium (ISM) follow advective CR transport within magnetized plasma, well anisotropic along local magnetic field. losses are included terms Coulomb hadronic interactions with thermal...

The magnetic fields observed in the Milky~Way and nearby galaxies appear to be equipartition with turbulent, thermal, cosmic ray energy densities, hence are expected dynamically important. However, origin of these strong is still unclear, most previous attempts simulate galaxy formation from cosmological initial conditions have ignored them altogether. Here, we analyse predicted by simulations Auriga Project, a set 30 high-resolution zoom Milky~Way-like galaxies, carried out moving-mesh...

Many bright radio relics in the outskirts of galaxy clusters have low inferred Mach numbers, defying expectations from shock acceleration theory and heliospheric observations that injection efficiency relativistic particles plummets at numbers. With a suite cosmological simulations, we follow diffusive as well radiative Coulomb cooling cosmic ray electrons during assembly cluster. We find substantial population fossil electrons. When reaccelerated (through acceleration), they are competitive...

ABSTRACT The physics of cosmic rays (CRs) is a promising candidate for explaining the driving galactic winds and outflows. Recent galaxy formation simulations have demonstrated need active CR transport either in form diffusion or streaming to successfully launch galaxies. However, due computational limitations, most previous modeled isotropically. Here, we discuss high-resolution isolated disk galaxies 10 11 M ⊙ halo with moving-mesh code Arepo that include injection CRs from supernovae,...

The thermal plasma of galaxy clusters lost most its information on how structure formation proceeded as a result dissipative processes. In contrast, non-equilibrium distributions cosmic rays (CRs) preserve the about their injection and transport processes provide thus unique window current past This can be unveiled by observations non-thermal radiative processes, including radio synchrotron, hard X-ray γ-ray emission. To explore this, we use high-resolution simulations sample spanning mass...

We investigate the interplay of cosmic ray (CR) propagation and advection in galaxy clusters. Propagation form CR diffusion streaming tends to drive radial profiles towards being flat, with equal number density everywhere. Advection by turbulent gas motions produce centrally enhanced profiles. assume that velocity is order sound velocity. This motivated plasma physical arguments. The then usually larger than typical velocities becomes comparable or lower this only for periods trans-...

We study the possibility for detecting gamma-ray emission from galaxy clusters. consider 1) leptophilic models of dark matter (DM) annihilation that include a Sommerfeld enhancement (SFE), 2) different representative benchmark supersymmetric DM, and 3) cosmic ray (CR) induced pion decay. Among all clusters/groups flux-limited X-ray sample, we predict Virgo, Fornax M49 to be brightest DM sources find particularly low CR-induced background Fornax. For minimum substructure mass given by...

Cosmic rays (CRs) have recently re-emerged as attractive candidates for mediating feedback in galaxies because of their long cooling timescales. They can energy densities comparable to the thermal gas, but do not suffer catastrophic losses. Recent simulations shown that momentum and deposited by CRs moving with respect ambient medium drive galactic winds. However, are hampered our ignorance details CR transport. Two key limits previously considered model transport a purely diffusive process...

ABSTRACT Multiphase galaxy winds, the accretion of cold gas through haloes, and stripping from jellyfish galaxies are examples interactions between hot gaseous phases. There two important regimes in such systems. A sufficiently small cloud is destroyed by wind as a result Kelvin–Helmholtz instabilities, which shatter into pieces that eventually mix dissolve wind. In contrast, stripped large mixes with to intermediate temperatures, then becomes thermally unstable cools, causing net tail....

About 1/3 of X-ray-luminous clusters show smooth, Mpc-scale radio emission, known as giant haloes. One promising model for haloes is Fermi-II acceleration seed relativistic electrons by compressible turbulence. The origin these has never been fully explored. Here, we integrate the Fokker-Planck equation cosmic ray (CR) electron and proton distributions when post-processing cosmological simulations cluster formation, confront them with surface brightness spectral data Coma. For standard...

Star formation in galaxies appears to be self-regulated by energetic feedback processes. Among the most promising agents of are cosmic rays (CRs), relativistic ion population interstellar and intergalactic plasmas. In these environments, CRs virtually collisionless interact via collective phenomena mediated kinetic-scale plasma waves large-scale magnetic fields. The enormous separation kinetic global astrophysical scales requires a hydrodynamic description. Here, we develop new macroscopic...

Jets from supermassive black holes in the centres of galaxy clusters are a potential candidate for moderating gas cooling and subsequent star formation through depositing energy intra-cluster gas. In this work, we simulate jet-intra-cluster medium interaction using moving-mesh magnetohydrodynamics code Arepo. Our model injects supersonic, low density, collimated magnetised outflows cluster centres, which then stopped by surrounding gas, thermalise inflate low-density cavities filled with...

Galactic winds exhibit a multiphase structure that consists of hot-diffuse and cold-dense phases. Here we present high-resolution idealized simulations the interaction hot supersonic wind with cold cloud moving-mesh code arepo in setups without radiative cooling. We demonstrate cooling causes clouds sizes larger than length to fragment 2D 3D simulations. confirm earlier by McCourt et al. (2018) highlight differences shattering processes are exposed wind. The fragmentation process is...