Related papers: The First Stars and Quasars
Microquasars are compact objects (stellar-mass black holes and neutron stars) that mimic, on a smaller scale, many of the phenomena seen in quasars. Their discovery provided new insights into the physics of relativistic jets observed…
Young stars form on a wide range of scales, producing aggregates and clusters with various degrees of gravitational self-binding. The loose aggregates have a hierarchical structure in both space and time that resembles interstellar…
Cosmic objects with magnetic fields (quasars, radiogalaxies) are observed at redshifts $z\geq 7$ (Wang et al., 2021, Fan et al., 2023, Yang et al., 2024) and more (for instance, for $z = 10.073\pm 0.002$, Goulding et al., 2023) indicates…
Massive stars blow powerful winds and eventually explode as supernovae. By doing so, they inject energy and momentum in the circumstellar medium, which is pushed away from the star and piles up to form a dense and expanding shell of gas.…
In popular cold dark matter cosmological scenarios, stars may have first appeared in significant numbers around a redshift of 10 or so, as the gas within protogalactic halos with virial temperatures in excess of 20,000 K (corresponding to…
The Interstellar Medium has a fractal structure, in the sense that gas and dust distribute in a hierarchical and self-similar manner. Stars in new-born cluster probably follow the same fractal patterns of their parent molecular clouds.…
Despite much recent theoretical and observational progress in our knowledge of the early universe, many fundamental questions remain only partially answered. Here, we review the latest achievements and persisting problems in the…
The development of primordial inhomogeneities into the non-linear regime and the formation of the first astrophysical objects within dark matter halos mark the transition from a simple, neutral, cooling universe -- described by just a few…
According to the current understanding of cosmic structure formation, the precursors of the most massive structures in the Universe began to form shortly after the Big Bang, in regions corresponding to the largest fluctuations in the cosmic…
The cosmic history of star formation is briefly reviewed, starting with the Milky Way and then discussing observations relevant to the closed box and hierarchical build-up models. Observations of local star formation are reviewed for…
We investigate the thermal and dynamical evolution of primordial gas clouds in the universe after decoupling. Comparing the time-scale of dynamical evolution with that of fragmentation, we can estimate the typical fragmentation scale. We…
Several planets have recently been discovered around old metal-poor stars, implying that these planets are also old, formed in the early Universe. The canonical theory suggests that the conditions for their formation could not have existed…
The chemical elements are created in nuclear fusion processes in the hot and dense cores of stars. The energy generated through nucleosynthesis allows stars to shine for billions of years. When these stars explode as massive supernovae, the…
We explore the consequences of a novel but increasingly well-supported hypothesis that supermassive black holes may have formed from primordial black holes form ed prior to, and rapidly growing in, the radiation-dominated universe. We show…
We investigate the dust properties and star-formation signature of galaxies in the early universe by stacking 111227 objects in the recently released COSMOS catalogue on maps at wavelengths bracketing the peak of warmed dust emission. We…
The cosmological background of ionizing radiation has been dominated by quasars once the Universe aged by ~2 billion years. At earlier times (redshifts z>3), the observed abundance of bright quasars declined sharply, implying that cosmic…
In spite of significant recent and ongoing research efforts, most of the early evolution and long-term fate of young massive star clusters remain clouded in uncertainties. Here, I discuss our understanding of the initial conditions of star…
I review some important questions in the field of massive star formation: What are the initial conditions for proto star clusters and how do they arise? What are the initial conditions for individual massive star formation within star…
The isothermal dynamical evolution of a clumpy and turbulent molecular cloud region and its fragmentation into a protostellar cluster is investigated numerically. The effect of different initial density and velocity distributions, generated…
Most star complexes are in fact complexes of stars, clusters and gas clouds; term "star complexes" was introduced as general one disregarding the preferential content of a complex. Generally the high rate of star formation in a complex is…