How to be a scientific realist: a normative-pragmatist proposal.

We investigate the viability of a cosmological scenario with interacting dark sector, which can describe the coexistence between dark energy and dark matter. The model possesses an analytical solution for the Hubble function and we constrain the free parameters by applying the newly released cosmic chronometers data (31 old data and 3 new data from DESI), the Baryonic Acoustic Oscillators from the Dark Energy Spectroscopic Instrument Survey (DESI DR2 BAO), along with Gamma-ray bursts (GRBs) and Supernova catalogues (Pantheon Plus, Union3, and DES-Dovekie). We find that the coexistence model fits the data sets in a better way than the reference models - the ΛCDM and w CDM models. The analysis shows that the coexistence scenario can provide a cosmologically viable model for the description of the late-time acceleration of the universe. Nevertheless, for large redshifts, the model has a similar behaviour to that of the w CDM model, as the introduction of the GRB data indicates in the statistical parameters. Finally, it is worth mentioning that the coexistence model provides a statistically smaller value for the H 0 parameter.

A test of invariance of halo surface density for FIRE-2 simulations with cold dark matter and self-interacting dark matter

Images of black holes in the center of Moore dark matter halo

Impact of baryons on the population of Galactic subhalos and implications for dark matter searches

Halo structure and lensing signatures of a polytropic dark matter fluid

Non-radial oscillations in dark matter admixed neutron stars using a two fluid formalism

The measurement of the cosmic-ray electron+positron flux at high energy is a key tool to look for possible astrophysical sources of high-energy electrons/positrons and indirect signals of dark matter. The current measurement of the electron+positron flux is limited to an energy of about 7 TeV, and it is insufficient to reach a clear conclusion on these two possible contributions. The limitation in energy is mainly due to the geometric acceptance of the current in-orbit space experiments. Thanks to the larger geometric factor, the future space experiment HERD will have a larger geometric factor and will extend the flux measurement up to tens of TeV. In this paper, using simulations, we study the performance of the calorimeter of the HERD experiment for the electron+positron flux measurement, demonstrating its capability to extend it up to 15 TeV and above.

Zoom-whirl orbital dynamics and Kludge gravitational waveforms in extreme mass-ratio inspirals near charged black holes surrounded by perfect fluid dark matter

Observationally guided redshift function: energy conditions, stability and dark matter implications

Galactic rotation curves are crucial for understanding the distribution of mass in galaxies. Despite advances in precision observations, there are discrepancies between the inferred mass from luminosity and the observed rotational velocities, often attributed to dark matter. While traditional parametric models provide valuable insights, they struggle with complex galactic features like prominent bulges and non-circular motions. In this study, we apply artificial neural networks to generate robust, data-driven models, tailored to each galaxy, for the rotation curves of spiral galaxies using high-quality observational data. Our approach demonstrates that neural networks can effectively capture the intricate structure of rotation curves without relying on predefined astrophysical assumptions. By comparing the data-based models with the Navarro-Frenk-White model under two different assumptions for the stellar component, we classify galaxies based on the model that best fits their rotation curves, offering insights into the limitations and strengths of both theoretical and data-based methods. This work highlights the potential of machine learning techniques in identifying galaxies whose dynamics are not well captured by standard theoretical models, pointing to the need for more refined physical descriptions.

Analyzing traversable wormholes supported by Taylor-Silk dark matter in Einstein gravity by using thin-shell stability with linearized radial perturbation

Gravitational freeze-in of scalar dark matter from environment-dependent kaluza-Klein moduli

Fungal communities in the freshwater systems of the semi-arid Narrabri region, Australia, remain largely unexplored despite their crucial role as ecosystem regulators. This study provides the first comprehensive survey of aquatic fungal diversity across the Narrabri region of riverine and lacustrine waters in an area over 2000 km2 in size. ITS amplicon sequencing of water samples collected in November 2022 and June 2023 identified 344 OTUs, revealing clear temporal variation, with OTU richness significantly higher in November than in June. Notably, ~73% of sequences could not be reliably assigned to phyla, representing substantial 'fungal dark matter', although many of these sequences appear to have affinities with poorly characterised zoosporic fungi. Aquatic hyphomycetes were virtually absent. This observation may be due to regular filtering of conidia by hyporheic or ephemeral flow during the dry season in this region. Notably, this study reported the first Australian record of the ectomycorrhizal fungus, Laccaria miniata, detected in a mass fruiting event in June 2023. Furthermore, this study demonstrated that two sponges, previously undocumented in the region, are widespread, alongside a novel gastrotrich species occurring at most locations. Taken together, these findings reveal semi-arid freshwater systems in Australia are hotspots of unrecognised fungal and eukaryote diversity.

We investigate the interplay between the weak gravity conjecture (WGC) and weak cosmic censorship conjecture (WCCC) for Reissner-Nordström anti-de Sitter (RN-AdS) black holes surrounded by perfect fluid dark matter (PFDM) within restricted phase space thermodynamics (RPST) and conformal field theory (CFT) thermodynamics frameworks. The WGC ensures that gravity must be the weakest force in any consistent quantum gravity theory, while the WCCC asserts that singularities from gravitational collapse must be hidden behind event horizons. We derive complete thermodynamic descriptions including mass, temperature, entropy, and free energy in both formalisms, accounting for PFDM parameterized by γ . Our analysis reveals characteristic swallowtail patterns in free energy curves, indicating van der Waals-like first-order phase transitions under specific parameter conditions. We demonstrate that the PFDM parameter γ and AdS radius ℓ play crucial roles in satisfying both conjectures. Significantly, we find that the compatibility range for WGC in CFT thermodynamics ( 3 ℓ < γ < 10 ℓ ) is substantially wider than in RPST ( 2 / 3 ℓ < γ < 5 ℓ ). This result suggests that the holographic dictionary acts as a natural filter for Swampland constraints, rendering the boundary CFT description more fundamental for consistency checks than the bulk thermodynamic variables. At critical points of black hole parameters, we verify simultaneous satisfaction of WGC and WCCC, demonstrating robustness within the critical framework. Our results provide compelling evidence that the holographic boundary description naturally encodes quantum gravity consistency conditions more efficiently than bulk thermodynamic formalisms, with perfect fluid dark matter serving as a crucial mediator enabling the reconciliation of these fundamental principles.

A new exact static and spherically symmetric black hole solution embedded in a cored Plummer dark matter halo is constructed. The impact of the cored Plummer dark matter halo on photon dynamics and its stablity, black hole shadow, eikonal limit quasinormal modes and black hole thermodynamics-phase transition are investigated. Light rings, gravitational lensing and shadow formation are studied based on the null geodesics which is derived via the principle of least action. The stability of circular photon orbits is characterized by the Lyapunov exponent, which is shown to control the imaginary part of massless quasinormal mode frequencies. The thermodynamic properties of the black hole-dark matter system are examined through the mass function, the analog black hole’s enthalpy, entropy, temperature, heat capacity and Gibbs free energy, from which the black hole phase transition is investigated. We analytically and graphically show how the cored Plummer dark matter halo modifies the black hole’s optical and thermodynamic behavior, enhancing null geodesic and thermodynamic stability also allowing phase transitions absent in pure Schwarzschild solution.

Physical viability of the general relativistic wormholes sourced by dark matter distributions

Probing dark matter with test mass motion in space-based gravitational wave detectors

Impact of perfect fluid dark matter on the shadow of rotating non-singular magnetic monopole

Symmetry-protected momentum exchange between dark matter and dark energy