Related papers: Constraints on Warm Dark Matter from Cosmological …
Dark matter constitutes the great majority of the matter content in the Universe, but its microscopic nature remains an intriguing mystery, with profound implications for particle physics, astrophysics and cosmology. Here we shed light on…
The unexpectedly large abundance of UV-bright galaxies at $z>10$ discovered by the James Webb Space Telescope poses a significant challenge to the standard $\Lambda$CDM cosmology. This work tests whether modifying the cosmological…
The reionization of the intergalactic medium (IGM) was likely inhomogeneous and extended. By heating the IGM and photo-evaporating gas from the outskirts of galaxies, this process can have a dramatic impact on the growth of structures.…
The mass and composition of dark matter (DM) particles and the shape and damping scales of the power spectrum of density perturbations can be estimated from recent observations of the DM dominated relaxed objects -- dwarf galaxies and…
We investigate the constraints on models of supermassive black hole (SMBH) and quasar formation obtainable from two recent observational developments: the discovery of luminous quasars at z~6, and estimates of the local mass density of…
We investigate the effects of warm dark matter (WDM) on the cosmic 21-cm signal. If dark matter exists as WDM instead of cold dark matter (CDM), its non-negligible velocities can inhibit the formation of low-mass halos that normally form…
The fraction of ionizing photons that escape their host galaxies to ionize hydrogen in the inter-galactic medium (IGM) is a critical parameter in analyses of the reionization era. In this paper we use the Meraxes semi-analytic galaxy…
Galaxies can form in a sufficiently deep gravitational potential so that efficient gas cooling occurs. We estimate that such potential is provided by a halo of mass $M \gtsim M_{c} \approx 7.0 \times 10^{12} ~ (\Delta_{c}(z)…
We explore the lowest mass limit that can be placed on the halo mass function in CDM using 28 strong gravitational lenses. For this purpose, we study an extreme model in which the halo mass function and mass-concentration relation follow…
Warm Dark Matter (WDM) has been invoked to resolve apparent conflicts of Cold Dark Matter (CDM) models with observations on subgalactic scales. In this work we provide a new and independent lower limit for the WDM particle mass (e.g.…
We provide a simple theoretical model for the quasar luminosity function at high redshifts that naturally reproduces the statistical properties of the luminous SDSS quasar sample at redshifts z~4.3 and z>5.7. Our model is based on the…
Warm dark matter (WDM) may resolve the possible conflict between observed galaxy halos and the halos produced in cold dark matter (CDM) simulations. Here we present an extension of MSSM to include WDM by adding a gauge singlet fermion,…
It is well known that annihilations in the homogeneous fluid of dark matter (DM) can leave imprints in the cosmic microwave background (CMB) anisotropy power spectrum. However, the relevance of DM annihilations in halos for cosmological…
The James Webb Space Telescope (JWST) has unveiled a population of unexpectedly massive and luminous galaxies at redshifts $z \gtrsim 7$, posing a significant challenge to the standard $\Lambda$CDM cosmological paradigm. In this work, we…
Observations of the redshifted 21-cm signal (in absorption or emission) allow us to peek into the epoch of "dark ages" and the onset of reionization. These data can provide a novel way to learn about the nature of dark matter, in particular…
We present the results of a numerical study comparing photometric and physical properties of simulated z=6-9 galaxies to the observations taken by the WFC3 instrument aboard the Hubble Space Telescope. Using cosmological hydrodynamical…
The flux power spectrum of the high resolution Lyman-$\alpha$ forest data exhibits suppression at small scales. The origin of this suppression can be due to long-sought warm dark matter (WDM) or to thermal effects, related to the largely…
Recent studies have reported tension between the presence of luminous, high-redshift galaxies and the halo mass functions predicted by standard cosmology. Here, an improved test is proposed using the presence of high-redshift Balmer breaks…
We analyse the formation of cosmic structures in models where the dark matter is dominated by light gravitinos with mass of $ 100$ eV -- 1 keV, as predicted by gauge-mediated supersymmetry (SUSY) breaking models. After evaluating the number…
Using a high-resolution cosmological numerical simulation, we have analyzed the evolution of galaxies at z~10 in a highly overdense region of the universe. These objects could represent the high redshift galaxies recently observed by the…