Related papers: Low-mass star formation triggered by early superno…
If a significant fraction of metals is in dust, star-forming cores with metallicity higher than a critical value ~10^{-6}-10^{-5}Z_sun are able to fragment by dust cooling, thereby producing low-mass cores. Despite being above the critical…
The apparent absence of stars in the Milky Way halo with -5 ~< [Fe/H] ~< -4 suggests that the gas out of which the halo stars were born experienced a period of low or delayed star formation after the local universe was lit up by the first,…
Anomalous surface abundances are observed in a fraction of the low-mass stars of Galactic globular clusters, that may originate from hot-hydrogen-burning products ejected by a previous generation of massive stars. We present and investigate…
We present preliminary results of stellar structure and nucleosynthesis calculations for some early stars. The study (still in progress) seeks to explore the expected chemical signatures of second generation low- and intermediate-mass stars…
Star-forming regions that are visible at 3.6 microns and Halpha but not in the u,g,r,i,z bands of the Sloan Digital Sky survey (SDSS), are measured in five nearby spiral galaxies to find extinctions averaging ~3.8 mag and stellar masses…
We study the gravitational fragmentation of cold accretion streams flowing into a typical first galaxy. We use a one-zone hydrodynamical model to examine the thermal evolution of the gas entering a 10^8 M_sun DM halo at z=10. The goal is to…
Direct collapse black hole (DCBH) formation with mass $\gtrsim 10^{5}~M_{\odot}$ is a promising scenario for the origin of high-redshift supermassive black holes. It has usually been supposed that the DCBH can only form in the primordial…
We consider a formation scenario for supramassive neutron stars (SMNSs) taking place through mass and angular momentum transfer from a close companion during a Low Mass X-ray Binary (LMXB) phase, with the ensuing suppression of the magnetic…
It has been proposed theoretically that the first generation of stars in the Universe (population III) would be as massive as 100 solar masses (100Mo), because of inefficient cooling of the precursor gas clouds. Recently, the most…
The direct collapse scenario, which predicts the formation of supermassive stars (SMSs) as precursors to supermassive black holes (SMBHs), has been explored primarily under the assumption of metal-free conditions. However, environments…
The oldest, most metal-poor stars in the Galactic halo and satellite dwarf galaxies present an opportunity to explore the chemical and physical conditions of the earliest star forming environments in the Universe. We review the fields of…
About 4.6 billion years ago, some event disturbed a cloud of gas and dust, triggering the gravitational collapse that led to the formation of the solar system. A core-collapse supernova, whose shock wave is capable of compressing such a…
We investigate the radiative transport of dust in primordial galaxies in the presence of the UV radiation field from the first metal-free stars. We find that dust created in the first supernova (SN) explosions can be driven through the…
The minimum initial mass required for a star to explode as an Fe core collapse supernova, typically denoted $M_\text{mas}$, is an important quantity in stellar evolution because it defines the border between intermediate mass and massive…
The first stars were likely more massive than those forming today and thus rapidly evolved, exploding as supernovae and enriching the surrounding gas with their chemical products. In the Local Group, the chemical signature of the first…
We investigate the first emergence of the so-called cold accretion, the accretion flows deeply penetrating a halo, in the early universe with cosmological N-body/SPH simulations. We study the structure of the accretion flow and its…
The extent to which turbulence mixes gas in the face of recurrent infusions of fresh metals by supernovae (SN) could help provide important constraints on the local star formation conditions. This includes predictions of the metallicity…
We study the formation of the first generation of stars in the standard cold dark matter model, using a very high-resolution hydordynamic simulations. Our simulation achieves a dynamic range of 10^{10} in length scale. With accurate…
Understanding star formation is problematic as it originates in the large scale dynamics of a galaxy but occurs on the small scale of an individual star forming event. This paper presents the first numerical simulations to resolve the star…
Population III (pop III) stars were born in halos characterised by a pristine gas composition. In such a halo, once the gas density reaches n$_{\mathrm{H}} \sim$ 1 cm$^{-3}$, molecular cooling leads to the collapse of the gas and the birth…