National Observatory of Athens

A Unified Scalar-Field Mechanism for the H0, S8 and Evolving Dark-Energy Tensions

I investigate whether one minimally coupled canonical scalar field can generate, in a single continuous cosmological history, the correlated changes in the sound horizon, late-time expansion, and structure growth that are relevant to the H0, evolving dark-energy, and S8 tensions....

Past and present generation of natural hydrogen at a convergent plate boundary – the case of Aotearoa New Zealand

Convergent margins provide an array of geological settings where serpentinization of ultramafic rocks may generate natural hydrogen. Aotearoa New Zealand (A-NZ) is an archetypal example of a convergent margin where tectonic assembly, spatiotemporal variability of serpentinization...

Nisyros Volcano Hydrothermal System Response to Temporal Stress Changes Inferred from Ambient Noise Interferometry

ABSTRACT Nisyros Island, located in the eastern Hellenic arc of the Aegean Sea, is an active volcanic island. Although seismic stations have sparsely sampled the area, ambient noise interferometry measurements revealed a significant coseismic velocity drop during the 2017 Kos ear...

Dust radiative effects and impact on energy production over the Mediterranean Basin

Abstract. Atmospheric aerosols are among the key factors affecting the Earth’s radiation budget, playing a fundamental role in understanding climate forcing, feedback mechanisms, and their impact on future climate projections and on solar energy systems. More specifically, dust a...

A sentiment analysis of public opposition to carbon capture and storage technology

Carbon capture and storage (CCS) is recognized as an important technology for reducing greenhouse gas emissions and achieving climate targets, yet some segments of society express public opposition. Public opposition, even when expressed by minority groups, has at times influence...

The influence of El Niño-Southern Oscillation on cool-season precipitation variability in the arid Middle East

Abstract. Interannual variability in precipitation across the Middle East is of high societal and environmental relevance given the region's arid climate and limited water resources. While previous studies have linked the El Niño-Southern Oscillation (ENSO) to interannual precipi...

Atomic clocks and gravitational waves as probes of non-metricity

Abstract Non-metricity provides a natural extension of Riemannian geometry, yet its experimental signatures remain largely unexplored. In this work we investigate how spacetime non-metricity can be probed through high-precision observations, focusing on atomic clocks and gravitat...

Highly suppressed tensor-to-scalar ratio from a modified Lennard–Jones inflationary potential

Abstract The increasingly stringent observational bounds on primordial gravitational waves strongly constrain inflationary model building, favoring scenarios that predict highly suppressed tensor perturbations. While many viable constructions rely on non-canonical kinetic terms,...