Advancements in Dark Matter Research: New Constraints and Models

Recent studies have made significant strides in dark matter research, providing new constraints and proposing novel models that enhance our understanding of this elusive component of the universe. A study titled 'Neural posterior estimation of the line-of-sight and subhalo populations in galaxy-scale strong lensing systems' explores how strong gravitational lensing can be used to study dark matter properties on sub-galactic scales. This research highlights the anisotropic features imprinted by line-of-sight halos on the lensing deflection fields, which are sensitive to the collisional nature of dark matter, potentially opening pathways to test alternatives to the cold dark matter paradigm. The authors, including Birendra Dhanasingham, note challenges in accurately recovering dark matter substructure mass functions, attributed to issues with training data and the fitting function used for analysis.

In another significant contribution, the paper 'Improved constraints on ultralight axions using latest observations of the early and late Universe' analyzes the properties of ultralight axions, hypothetical particles that could behave as dark matter or dark energy. This study utilizes data from the cosmic microwave background (CMB) and baryon acoustic oscillations (BAO) to place new upper bounds on the energy density fraction of ultralight axions to total dark matter, suggesting that future measurements will further refine our understanding of these particles. The research indicates that while the signatures of ultralight axions are subtle, they may present distinct cosmological imprints that could lead to new revelations in dark matter research.

Additionally, the paper 'How Complex is Dark Energy? A Bayesian Analysis of CPL Extensions with Recent DESI BAO Measurements' addresses the nature of dark energy and its relationship with dark matter. The study's Bayesian analysis, which incorporates data from the Cosmic Microwave Background and DESI measurements, supports the idea of an evolving dark energy component, challenging the adequacy of overly complex models. It finds that simpler two-parameter forms capture the dynamics of dark energy effectively, reinforcing recent signals for dynamical dark energy observed by DESI collaboration.

Moreover, 'Constraining Axion Dark Matter with Galactic-Centre Resonant Dynamics' explores the dynamics of stars at the Galactic center influenced by fuzzy dark matter cores. The research indicates that the presence of a super-massive black hole within these dense cores can significantly affect stellar orbits, introducing a new gravitational component that must be considered in Galactic-center models. This study provides constraints on the mass of the particles constituting these cores, emphasizing the importance of future data in tightening these constraints further. These advancements across various studies reflect a growing understanding of dark matter, its properties, and implications for cosmology, paving the way for future research in this enigmatic area of physics.