Article
Astronomy & Astrophysics
Camila A. Correa, Matthieu Schaller, Sylvia Ploeckinger, Noemi Anau Montel, Christoph Weniger, Shin'ichiro Ando
Summary: We introduce the TangoSIDM project, a suite of cosmological simulations that explore the impact of large dark matter scattering cross-sections over dwarf galaxy scales. The simulations accurately model core formation and gravothermal core collapse, showing that the velocity-dependent cross-sections produce a large diversity in the circular velocities of satellite haloes. This research offers a promising explanation for the diversity in density and velocity profiles observed in dwarf galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Vicente Delgado, Antonio Munoz Mateo
Summary: This study assumes dark matter to be a cosmological self-gravitating Bose-Einstein condensate comprised of non-relativistic ultralight scalar particles with competing gravitational and repulsive contact interactions. It explores the observational implications of this model and finds that dark matter structures can form stable self-bound structures exhibiting a universal mass profile and rotation curve.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yun Liu, Shihong Liao, Xiangkun Liu, Jiajun Zhang, Rui An, Zuhui Fan
Summary: The interacting dark energy (IDE) model provides a natural mechanism to address the coincidence problem and relieve observational tensions under the ΛCDM model. However, current observational data are insufficient to effectively distinguish IDE models from ΛCDM, and additional information from non-linear structure formation is needed. For the model with dark matter decaying into dark energy, the structure formation is slowed down and the properties of dark matter haloes are inconsistent with observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Stephanie O'Neil, Mark Vogelsberger, Saniya Heeba, Katelin Schutz, Jonah C. Rose, Paul Torrey, Josh Borrow, Ryan Low, Rakshak Adhikari, Mikhail Medvedev, Tracy R. Slatyer, Jesus Zavala
Summary: Self-interacting dark matter (SIDM) can alleviate discrepancies between simulated cold dark matter (CDM) and observed galactic properties. We propose a physically motivated SIDM model with a nearly degenerate excited state that allows for both elastic and inelastic scattering. Our simulations show that up-scattering reactions increase the central densities of the main halo, but coring still occurs due to elastic and down-scattering effects.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
S. T. H. Hartman, H. A. Winther, D. F. Mota
Summary: This study performs fully 3D cosmological simulations of scalar field dark matter with self-interactions, also known as Bose-Einstein condensate dark matter. The simulations are based on a set of effective hydrodynamic equations derived from the non-linear Schrodinger equation. The results show that the formed dark matter halos have Navarro-Frenk-White envelopes and cored centers due to fluid pressures. The core radii are largely determined by the self-interaction Jeans' length, while the effective thermal energy becomes important as structures collapse. Comparisons with observations of Milky Way dwarf spheroidals and nearby galaxies suggest that the simulated population of halos does not match well but performs better compared to simulations of fuzzy dark matter-only.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
T. Harko, K. Asadi, H. Moshafi, H. Sheikhahmadi
Summary: This study investigates the effects of interaction, decay, and particle generation in a many-component Universe using an approach based on open system thermodynamics. By introducing particle number balance equations and creation pressures, the cosmological evolution equations are thermodynamically consistent. Constrained by multiple observational data sets, this model provides a solution to the Hubble tension problem.
PHYSICS OF THE DARK UNIVERSE
(2022)
Article
Astronomy & Astrophysics
Niklas Becker, Deanna C. Hooper, Felix Kahlhoefer, Julien Lesgourgues, Nils Schoeneberg
Summary: Researchers explored the possibility of dark matter interacting simultaneously with photons, baryons, and dark radiation, using a new version of the Boltzmann code to reassess cosmological bounds in multi-interacting dark matter scenarios. Their study found that the combination of dark matter-photon and dark matter-DR interactions could potentially alleviate cosmological tensions.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Edoardo Giangrandi, Violetta Sagun, Oleksii Ivanytskyi, Constanca Providencia, Tim Dietrich
Summary: We propose a model of asymmetric bosonic dark matter with self-repulsion. By studying different distribution regimes, we find that condensed dark matter leads to smaller radius and tidal deformability compared to pure baryonic stars, while the presence of a dark matter halo increases the tidal deformability and total gravitational mass. We impose constraints on the model parameters based on the self-interaction cross section of dark matter and discuss smoking gun evidence of dark matter presence.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Monica N. Castillo-Santos, A. Hernandez-Almada, Miguel A. Garcia-Aspeitia, Juan Magana
Summary: The dynamics of the Universe was analyzed using an exponential function for the dark energy equation of state, known as Gong-Zhang parameterization. The model's free parameters were constrained using various measurements, and it was found that the exponential model is preferred when the data are separated. The cosmological parameters and the age of the Universe were estimated based on the Joint analysis.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
Helen Meskhidze, Francisco J. Mercado, Omid Sameie, Victor H. Robles, James S. Bullock, Manoj Kaplinghat, James O. Weatherall
Summary: Self-interacting dark matter (SIDM) models have been extensively studied as solutions to the small-scale puzzles in astrophysics. In this research, the implementation of dark matter self-interactions in two simulation codes, Gizmo and AREPO, were investigated. The study found good agreement between the codes for the density profile during the core expansion phase, indicating that these codes can reliably differentiate between different cross-sections, but further investigation is needed for finer distinctions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Eleonora Di Valentino, Alessandro Melchiorri, Olga Mena, Supriya Pan, Weiqiang Yang
Summary: Recent measurements by the Planck satellite suggest a preference for a closed universe, but this conflicts with low redshift observables such as Type Ia supernovae luminosity distances. Interacting dark energy models could help reconcile these discrepancies in a closed Universe, indicating potential for a different coupling and curvature above 99% confidence level. This highlights the significance of broader cosmological data analyses and the possibility of better agreement between theory and observations by relaxing flatness and vacuum energy assumptions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Purusottam Ghosh, Partha Konar, Abhijit Kumar Saha, Sudipta Show
Summary: This study examines the non-thermal production of dark matter in a scalar extended singlet doublet fermion model. The presence of a modified cosmological phase in the early era drives the fermion dark matter to satisfy nearly the entire observed relic abundance. It is also suggested that the unconventional cosmological history assumption allows for the detection of GeV scale dark matter at LHC from displaced vertex signatures with improved sensitivity.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Suryakanta Swain, Debasis Sahu, Debabrata Dwivedee, Gourishankar Sahoo, Bibekananda Nayak
Summary: The recent observations of accelerated expansion of the universe present a challenge for theoretical understanding. In this study, a dynamical dark energy model is proposed, which explains the acceleration by considering the interaction between dark energy and matter. The analysis predicts a phantom-dominated universe and a transition from deceleration to acceleration in the past.
ASTROPHYSICS AND SPACE SCIENCE
(2022)
Article
Astronomy & Astrophysics
Vishal Parmar, H. C. Das, M. K. Sharma, S. K. Patra
Summary: This study analyzes the properties of magnetized neutron stars with dark matter. The equation of state is softer with the presence of dark matter and magnetic fields affect different macroscopic properties such as mass, radius, and tidal deformability. The change in neutron star observables is proportional to the amount of dark matter and the strength of the magnetic field.
Article
Astronomy & Astrophysics
Daniel Egana-Ugrinovic, Rouven Essig, Daniel Gift, Marilena LoVerde
Summary: This study investigates the evolution of cosmological perturbations in dark-matter models with elastic and velocity-independent self interactions, analyzing the differences between self-interacting dark matter and conventional warm dark matter in terms of power suppression mechanisms on small scales. By performing computations of the linear power spectrum using a newly developed Boltzmann code, the researchers found that novel bounds on light scalar singlet dark matter could be set, with relaxed limits on warm dark matter when self interactions are included at their maximal value consistent with bounds from the Bullet Cluster.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Nelson R. F. Braga, Octavio C. Junqueira
Summary: This study investigates the influence of rotation on the transition temperature of strongly interacting matter produced in non-central heavy ion collisions. By using a holographic description of an AdS black hole, the authors extend the analysis to the more realistic case where the matter spreads over a region around the rotational axis. The results show the coexistence of confined and deconfined phases and are consistent with the concept of local temperature in rotating frames developed by Tolman and Ehrenfest.
Article
Astronomy & Astrophysics
Bing Sun, Jiachen An, Zhoujian Cao
Summary: This paper investigates the effect of gravitational constant variation on the propagation of gravitational waves. By employing two analytical methods, the study finds that variations in the gravitational constant result in amplitude and phase corrections for gravitational waves, and the time variation of the gravitational constant can be constrained through the propagation of gravitational waves.
Article
Astronomy & Astrophysics
Abdellah Touati, Zaim Slimane
Summary: This letter presents the first study of Hawking radiation as a tunneling process within the framework of non-commutative gauge theory of gravity. The non-commutative Schwarzschild black hole is reconstructed using the Seiberg-Witten map and the star product. The emission spectrum of outgoing massless particles is computed using the quantum tunneling mechanism. The results reveal pure thermal radiation in the low-frequency scenario, but a deviation from pure thermal radiation in the high-frequency scenario due to energy conservation. It is also found that noncommutativity enhances the correlations between successively emitted particles.
Article
Astronomy & Astrophysics
Shahar Hod
Summary: The travel times of light signals between two antipodal points on a compact star's surface are calculated for two different trajectories. It is shown that, for highly dense stars, the longer trajectory along the surface may have a shorter travel time as measured by asymptotic observers. A critical value of the dimensionless density-area parameter is determined for constant density stars to distinguish cases where crossing through the star's center or following a semi-circular trajectory on the surface has a shorter travel time as measured by asymptotic observers.
