Related papers: Finding the First Cosmic Explosions. III. Pulsatio…
Supermassive black holes observed at high redshift $z\gtrsim6$ could grow from direct collapse black holes (DCBHs) with mass $\sim10^5\,M_{\odot}$, which result from the collapse of supermassive stars (SMSs). If a relativistic jet is…
Stars emit MeV neutrinos during their evolution via nuclear syntheses and thermal processes, and detecting them could provide insights into stellar structure beyond what is accessible through electromagnetic wave observations. So far, MeV…
When a core-collapse supernova explodes in a binary star system, the ejecta might encounter an overdense shell, where the stellar winds of the two stars previously collided. In this work, we investigate effects of such interactions on…
IceCube collaboration has seen an unexpected population of high energy neutrinos compatible with an astrophysical origin. We consider two categories of events that can help to diagnose cosmic neutrinos: double pulse, that may allow us to…
A forefront area of research concerns the exploration of the properties of hadronic matter under extreme conditions of temperature and density, and the determination of the equation of state--the relation between pressure, temperature and…
Hydrogen-rich core collapse supernovae, known as "Type II" supernovae, are the most common type of stellar explosion realized in nature. They are defined by the presence of prominent hydrogen lines in their spectra. Type II supernovae are…
Massive stars undergo fundamental-mode and first-overtone radial pulsations with periods of 100-1000 days as Red Supergiants (RSGs). At large amplitudes, these pulsations substantially modify the outer envelope's density structure…
We consider the possibility that the excess of cosmic rays near $\sim 10^{18}$ eV, reported by the AGASA and SUGAR groups from the direction of the Galactic Center, is caused by a young, very fast pulsar in the high density medium. The…
Supermassive primordial stars in hot, atomically-cooling haloes at $z \sim$ 15 - 20 may have given birth to the first quasars in the universe. Most simulations of these rapidly accreting stars suggest that they are red, cool hypergiants,…
We study the formation of massive Population III binary stars using a newly developed radiation hydrodynamics code with the adaptive mesh refinement and adaptive ray-tracing methods. We follow the evolution of a typical primordial…
Some ancient, dim, metal-poor stars may have formed in the ashes of the first supernovae (SNe). If their chemical abundances can be reconciled with the elemental yields of specific Population III (Pop III) explosions, they could reveal the…
Ultrahigh energy cosmic rays are the most energetic of any subatomic particles ever observed in nature. The quest for their mysterious origin is currently a major scientific challenge. Here we explore the possibility that these particles…
Detection of the radiation emitted from some of the earliest galaxies will be made possible in the next decade, with the launch of the James Webb Space Telescope (JWST). A significant fraction of these galaxies may host Population (Pop) III…
Type II-P supernov\ae~(SNe), the most common core-collapse SNe type, result from the explosions of red supergiant stars. Their detection in the radio domain testifies of the presence of relativistic electrons, and shows that they are…
The absence of direct high redshift observations poses a significant challenge in understanding the properties of first stars. Nonetheless, the cumulative effect of entire stellar populations can be studied with current data. In this work…
As gravitational wave instrumentation becomes more sensitive, it is interesting to speculate about subtle effects that could be analyzed using upcoming generations of detectors. One such effect that has great potential for revealing the…
Three regions of excessive flux of cosmic rays with energies of the order of PeV are found in the experimental data of the EAS MSU array at a confidence level greater than 4\sigma. For two of them, there are similar regions in the…
We use three-dimensional smoothed particle hydrodynamics simulations together with a dynamical ray-tracing scheme to investigate the build-up of the first H ii regions around massive Population III stars in minihaloes. We trace the highly…
Quasars at early redshifts ($z > 6$) with companion galaxies offer unique insights into the growth and evolution of the first supermassive black holes. Here, we report on a 150 ks Chandra observation of PSO J308.0416$-$21.2339, a $z=6.23$…
If the first (PopIII) stars were very massive, their final fate is to collapse into very massive black holes. Once a proto-black hole has formed into the stellar core, accretion continues through a disk. It is widely accepted, although not…