Conveners
Parallel 2D - Simulations/Cosmology
- Julian Munoz (Harvard-Smithsonian Center for Astrophysics)
Parallel 2D - Simulations/Cosmology
- Xiaoyong Chu (Institute of High Energy Physics (Vienna, Austria))
Despite its remarkable success, the standard LCDM paradigm has been challenged lately by significant tensions between different datasets. This has reinvigorated interest in beyond-LCDM models, such as dark matter models with interactions or non-negligible velocities, known collectively as non-cold dark matter. These models result in a suppression of the matter power spectrum on small scales,...
Stellar streams are very old, dynamical objects consisting of a collection of stars that originate from tidal disruptions of a globular cluster. In a galaxy like the Milky Way, these systems have the potential to be an extremely sensitive probe of dark matter substructure, baryonic physics, and the evolution history of the stream. In principle, this can be achieved by combining high precision...
The properties of dark matter halos and subhalos on sub-galactic scales, below 10^9 solar masses, depend on the formation mechanism, mass, and possible interactions of the dark matter particle, as well as the initial conditions for structure formation determined by the primordial matter power spectrum and inflation. As such, inferences of the abundance and density profiles of low-mass halos...
In this work, we carry out a suite of specially-designed numerical simulations to shed further light on dark matter (DM) subhalo survival at mass scales relevant for gamma-ray DM searches, a topic subject to intense debate nowadays. Specifically, we have developed and employed an improved version of DASH, a GPU $N$-body code, to study the evolution of low-mass subhaloes inside a Milky Way-like...
Uncovering the nature of dark matter (DM) is one of the most pressing pursuits in modern physics and cosmology. Astronomical observations are the key to understand the nature of DM and have been revealing the possibility that DM particles interact non-gravitationally with each other. It began with observations of the collision of nearby galaxy clusters. More recently, measurements of large DM...
Precision analysis of galaxy-galaxy strong gravitational lensing images provides a unique way of characterizing dark matter (DM) low-mass halos and could allow us to uncover the fundamental properties of DM's constituents. In recent years, gravitational imaging techniques made it possible to detect a few heavy subhalos. However, gravitational lenses contain numerous subhalos and line-of-sight...
Due to the coherent behavior of ultra-light dark matter (ULDM), in the central region of the dark matter halos, solitonic cores can form and change the small-scales predictions of the $\Lambda$CDM model. Analogously to the condensed matter systems, a rotating condensate halo can form defects with important observational consequences. These defects were observed numerically; however, a...
We examine the degree of spatial coherence of the field configuration in fuzzy dark matter halos. The compact soliton sitting at the centre of a halo is completely coherent and is surrounded by an incoherent field whose density follows the Navarro-Frenk-White profile and exhibits turbulent features. This spatial transition from coherence to incoherence can be well characterized by two...
The nature of dark matter, one of the major components of the cosmic standard model, remains one of the outstanding problems in physics. One interesting model is scalar field dark matter (SFDM), which fits naturally into observations in both particle physics and cosmology. Simulations and calculations using SFDM often use a classical field approximation (MFT) of the underlying quantum field...
Fuzzy Dark Matter (FDM) models admit self-similar solutions which are very different from their Cold Dark Matter (CDM) counterparts and do not converge to the latter in the semiclassical limit. In contrast with the familiar CDM hierarchical collapse, they correspond to an inverse-hierarchy blow-up. Constant-mass shells start in the nonlinear regime, at early times, with small radii and high...
In this talk, I will present a Neural Network-improved version of DarkHistory, a code package that self-consistently computes the early universe temperature, ionization levels, and photon spectral distortion due to exotic energy injections. We use simple multilayer perceptron networks to store and interpolate complicated photon and electron transfer functions, previously stored as large...
Compact stellar objects are promising cosmic laboratories to test fundamental interactions, in particular they could shed light on the nature of dark matter (DM). DM captured by the strong gravitational field of these stellar remnants transfers kinetic energy to the star during the collision. This together with further DM annihilation in the stellar interior can have various observational...
Thermal dark matter scenarios are characterized by an exponential decrease in the comoving dark matter number density as the temperature drops below the dark matter mass in the early Universe. In this talk, we will discuss a novel thermal framework, bouncing dark matter, where the abundance instead undergoes a ``bounce:" a transition from the exponential fall to an exponential rise, resulting...
Unusual masses of black holes being discovered by gravitational wave experiments pose fundamental questions about their origin. More interestingly, black holes with masses smaller than the Chandrasekhar limit (1.4 solar mass) are essentially impossible to produce through any standard stellar evolution. Primordial black holes, with fine-tuned parameters, and with no compelling formation...
