Related papers: Hidden BL Lacertae Objects Near and Far
The evolution of marginally bound supercluster-like objects in an accelerating LambdaCDM Universe is followed, by means of cosmological simulations, from the present time to an expansion factor a = 100. The objects are identified on the…
Evolution equations for multiplicities in QCD cascades can, both in the parton and dipole picture, be used to estimate corrections beyond the formal accuracy of the modified leading log approximation (MLLA). The differences between the two…
Aims: Intranight variation (or microvariation) is a common phenomenon of radio-loud BL Lac objects. However, it is not clear whether the recently found radio-quiet BL Lac objects have the same properties. The occurrence rate of intranight…
After two decades of direct dynamical simulation of large-scale structure in the universe, it is safe to say the subject is now mature. Still, there are parts of the problem that are less well developed than others. In general, the…
Cosmology is living through fascinating times, where new observations from ground and space telescopes are questioning the established paradigm, the so-called Lambda Cold Dark Matter model. The particle nature of Dark Matter is severely…
BL Lac objects (BLL) are defined by the presence of very weak (typically $<$ 5 {\AA}) or even absent spectral lines. This makes determining their distance particularly challenging, especially at high redshift, where the sources are fainter…
We study the effects of inhomogeneities on the evolution of the Universe, by considering a range of cosmological models with discretized matter content. This is done using exact and fully relativistic methods that exploit the symmetries in…
On small scales the observable Universe is highly inhomogeneous, with galaxies and clusters forming a complex web of voids and filaments. The optical properties of such configurations can be quite different from the perfectly smooth…
QCD predicts the existence of the perturbative Pomeron and of the Odderon. But both of them appear to be rather difficult to observe experimentally. We describe the experimental status of these two objects, discuss possible reasons for…
The standard model of cosmology considers the existence of two components of unknown nature, ``dark matter'' and ``dark energy'', which determine the cosmological evolution. Their nature remains unknown, and other models can also be…
Advancements in our understanding of exoplanetary atmospheres, from massive gas giants down to rocky worlds, depend on the constructive challenges between observations and models. We are now on a clear trajectory for improvements in…
The coincidence problem of late cosmic acceleration constitutes a serious riddle with regard to our understanding of the evolution of the Universe. Here we argue that this problem may someday be solved -or better understood- by expressing…
The LCDM cosmological model assumes the existence of a small cosmological constant in order to explain the observed accelerating cosmic expansion. Despite the dramatic improvement of the quality of cosmological data during the last decade…
The increase in discovered close binary central stars of planetary nebulae is leading to a sufficiently large sample to begin to make broader conclusions about the effect of close binary stars on common envelope evolution and planetary…
Multiple hypotheses/models have been put forward regarding the cooling history of the Earth. The search for life beyond Earth has brought these models into a new light as they connect to one of the two energy sources life can tap. The…
The Galactic centre and its surrounding space are important in studying galaxy-scale evolution, and stellar populations therein are expected to have imprints of the long-term evolution. Interstellar extinction, however, severely limits…
I address the need for deep blazar surveys by showing that our current understanding of blazars is based on a relatively small number of intrinsically luminous sources. I then review the on-going deeper surveys, addressing in particular…
Modern observations based on general relativity indicate that the spatial geometry of the expanding, large-scale Universe is very nearly Euclidean. This basic empirical fact is at the core of the so-called "flatness problem", which is…
The properties of the Extreme Horizontal Branch stars are quite well understood, but much uncertainty surrounds the many paths that bring a star to this peculiar configuration. Asteroseismology of pulsating EHB stars has been performed on a…
The present rate of the expansion of our Universe, the Hubble constant, can be predicted from the cosmological model using measurements of the early Universe, or more directly measured from the late Universe. But as these measurements…