Related papers: Statistical and dynamical decoupling of the IGM fr…
Quasar absorption lines now permit a direct probe of deuterium abundances in primordial material, with the best current estimate $ (D/H)=1.9\pm 0.4 \times 10^{-4}$. If this is the universal primordial abundance $(D/H)_p$, Standard Big Bang…
We compare assembly of DM halos with and without baryons, within the context of cosmological evolution in the LCDM WMAP3 Universe (baryons+DM, BDM model, and pure DM, PDM model). In representative PDM and BDM models we find that baryons…
It is now widely accepted that most of mass--energy in the universe is unobserved except by its gravitational effects. Baryons make only about 4% of the total, with "dark matter" making up about 23% and the "dark energy" responsible for the…
The inability of primordial baryonic density fluctuations, as observed in the cosmic microwave background (CMB), to grow into the present day astronomical structures is well established, under Newtonian and Einsteinian gravity. It is hence…
Rotation curves of spiral galaxies \emph{i}) fall off much less steeply than the Keplerian curves do, and \emph{ii}) have asymptotic speeds almost proportional to the fourth root of the mass of the galaxy, the Tully-Fisher relation. These…
Theoretically, the running of the cosmological constant in the IR region is not ruled out. On the other hand, from the QFT viewpoint, the energy released due to the variation of the cosmological constant in the late universe cannot go to…
The near equality of the dark matter and baryon energy densities is a remarkable coincidence, especially when one realizes that the baryon mass is exponentially sensitive to UV parameters in the form of dimensional transmutation. We explore…
The large scale structure of the present Universe is determined by the growth of dark matter density fluctuations and by the dynamical action of dark energy and dark matter. While much progress has been made in recent years in constraining…
A fine balance between dark and baryonic mass is observed in spiral galaxies. As the contribution of the baryons to the total rotation velocity increases, the contribution of the dark matter decreases by a compensating amount. This poses a…
The interplay between dark matter (DM) and baryons has long been ignored when building galaxies semi-empirically and observationally. Here I show that baryonic gravity leads to an adiabatic contraction of DM halos, which is most significant…
We split the total matter fluid into a bound (halo) component and an unbound (free particles) fluid component that is accreted by the halos. We adopt a different framework that treats the structure formation problem as a gravitational…
We point out that current constraints on dark matter imply only that the majority of dark matter is cold and collisionless. A subdominant fraction of dark matter could have much stronger interactions. In particular, it could interact in a…
In the present universe visible and dark matter contribute comparable energy density although they have different properties. This coincidence can be elegantly explained if the dark matter relic density, originating from a dark matter…
We derive new constraints on the non-gravitational baryon-dark-matter scattering (BDMS) by evaluating the mass thresholds of dark matter (DM) haloes in which primordial gas can cool efficiently to form Population III (Pop III) stars, based…
The recent detection of microlensing of stars of LMC by compact objects in the halo of our galaxy suggests that our galaxy is surrounded by a non-luminous halo made of compact objects with mass of about $(0.03-0.5) \msun$. The rate of…
Both simulations and observations indicate that the so-called missing baryons reside in the intergalactic medium known as the warm-hot intergalactic medium (WHIM). In this study we employed the IllustrisTNG50-1 simulation to demonstrate…
A spherical Lagrangian hydrodynamical code has been written to study the formation of cosmological structures in the early Universe. In this code we take into account the presence of collisionless non-baryonic cold dark matter (CDM), the…
We investigate the influence of dark energy on structure formation, within five different cosmological models, namely a concordance $\Lambda$CDM model, two models with dynamical dark energy, viewed as a quintessence scalar field (using a RP…
When bars form within galaxy formation simulations in the standard cosmological context, dynamical friction with dark matter (DM) causes them to rotate rather slowly. However, almost all observed galactic bars are fast in terms of the ratio…
In the standard model of cosmology, the background evolution of the Universe can in general be adequately described by general relativity and a uniform and isotropic metric minimally coupled with a collection of perfect fluids. These fluids…