Related papers: Quasar Redshifts: The Intrinsic Component
Understanding the expansion of the Universe remains a profound challenge in fundamental physics. The complexity of solving General Relativity equations in the presence of intricate, inhomogeneous flows has compelled cosmological models to…
We present a new sample of strong gravitational lens systems where both the foreground lenses and background sources are early-type galaxies. Using imaging from HST/ACS and Keck/NIRC2, we model the surface brightness distributions and show…
The redshift-luminosity distributions for well-defined galaxies and quasars in the Sloan Digital Sky Survey (SDSS) are compared for the two redshift-distance relations of a Hubble redshift and a de Sitter redshift. Assuming a Hubble…
The exploration of the redshift drift, a direct measurement of cosmological expansion, is expected to take several decades of observation with stable, sensitive instruments. We introduced a new method to probe cosmology which bypasses the…
Gas outflows appear to be a phenomenon shared by the vast majority of quasars. Observations indicate that there is wide range in outflow prominence. In this paper we review how the 4D eigenvector 1 scheme helps to organize observed…
The contribution of cosmological perturbations to the time drift of the cosmological redshift is derived. It is shown that the dominant correction arises from the local acceleration of both the emitter and the observer. The amplitude of…
The process of forming an image of a cosmological point source (CPS) in condition of high optical depth is considered accounting for all types of interactions. It is shown that the energy conservation law causes the size of this image which…
The origin of the extragalactic $\gamma$-ray background permeating throughout the Universe remains a mystery forty years after its discovery. The extrapolated population of blazars can account for only half of the background radiation at…
Quasar (or QSO) elemental abundances provide unique probes of high-redshift star formation and galaxy evolution. There is growing evidence from both the emission and intrinsic absorption lines that QSO environments have roughly solar or…
The peculiar velocity of the intergalactic gas responsible for the cosmic 21cm background from the epoch of reionization and beyond introduces an anisotropy in the three-dimensional power spectrum of brightness temperature fluctuations.…
Energy production due to the Casimir effect is considered for the case of a superdense state of matter, which can appear in such cosmological objects as white dwarfs, neutron stars, quasars and so on. The energy output produced by the…
The luminosity distance-redshift relation is one of the fundamental tools of modern cosmology. We compute the luminosity distance-redshift relation in a perturbed flat matter-dominated Universe, taking into account the presence of…
Observations of cosmic rays have been improving at all energies, with higher statistics and reduced systematics. Fundamental questions remain regarding the origins of cosmic rays both within the Galaxy and in extragalactic sources, and new…
We review the experimental evidences about flux and mass composition of ultra high energy cosmic rays in connection with theoretical scenarios concerning astrophysical sources. In this context, we also address the discussion about the…
High redshift radio galaxies are among the largest, most luminous, most massive, and most beautiful objects in the Universe. They are generally identified from their radio emission, thought to be powered by accretion of matter onto…
Using recent measurements of the spectrum and chemical composition of the highest energy cosmic rays, we consider the sources of these particles. We find that the data strongly prefers models in which the sources of the ultra-high energy…
The matter bounce scenario allows for a sizable parameter space where cosmological fluctuations originally exited the Hubble radius when the background energy density was small. In this scenario and its extended versions, the low energy…
A majority of quasar surveys have been based on criteria which assume strong blue continua or a UV-excess. Any amount of dust along the line-of-sight is expected to drastically extinguish the optical/UV flux leading to a selection bias.…
Quasars with redshifts greater than 4 are rare, and can be used to probe the structure and evolution of the early universe. Here we report the discovery of six new quasars with $i$-band magnitudes brighter than 19.5 and redshifts between…
Cosmic rays are energetic charged particles from extraterrestrial sources, with the highest energy events thought to come from extragalactic sources. Their arrival is infrequent, so detection requires instruments with large collecting…