相关论文: First stars, very massive black holes and metals

It has frequently been suggested that the stellar IMF in galaxies was top-heavy at early times. This would be plausible physically if the IMF depends on a mass scale such as the Jeans mass that was higher at earlier times because of the…

The initial mass function (IMF) of the first (Population III) stars and Population II (Pop II) stars is poorly known due to a lack of observations of the period between recombination and reionization. In simulations of the formation of the…

The most metal-poor stars record the earliest metal enrichment triggered by Population III stars. By comparing observed abundance patterns with theoretical yields of metal-free stars, physical properties of their first star progenitors can…

The first stars fundamentally transformed the early Universe through their production of energetic radiation and the first heavy chemical elements. The impact on cosmic evolution sensitively depends on their initial mass function (IMF),…

Magnetic fields play an important role for the formation of stars in both local and high-redshift galaxies. Recent studies of dynamo amplification in the first dark matter haloes suggest that significant magnetic fields were likely present…

In order to constrain the initial mass function (IMF) of the first generation of stars (Population III), we investigate the fragmentation properties of metal-free gas in the context of a hierarchical model of structure formation. We…

The distribution of stellar masses that form in one star-formation event in a given volume of space is called the initial mass function (IMF). The IMF has been estimated from low-mass brown dwarfs to very massive stars. Combining IMF…

We review recent advances in our understanding of the origin of the initial mass function (IMF). We emphasize the use of numerical simulations to investigate how each physical process involved in star formation affects the resulting IMF. We…

We critique the hypothesis that the first stars were very massive stars (VMS; M > 140 Msun). We review the two major lines of evidence for the existence of VMS: (1) that the relative metal abundances of extremely metal-poor Galactic halo…

Studies of the broad emission-line regions (BLRs) in quasars have revealed solar or higher enrichment levels up to the highest redshifts. In combination with the presence of large amounts of dust in QSOs at $z$ about 6, this implies that…

The theory for the formation of the first population of stars (Pop III) predicts an initial mass function (IMF) dominated by high-mass stars, in contrast to the present-day IMF, which tends to yield mostly stars with masses less than 1…

The first generations of stars ionised and enriched their host galaxies and seeded the growth of massive black holes. Models often assume that Pop III stellar masses in different minihaloes are stochastic realisations of a single universal…

We compare elemental abundance patterns of $\sim 200$ extremely metal-poor (EMP; [Fe/H]$<-3$) stars with supernova yields of metal-free stars in order to obtain insights into the characteristic masses of the first (Population III or Pop…

The first bound star-forming systems in the universe are predicted to form at redshifts of about 30 and to have masses of the order of 10^6 M_sun. Although their sizes and masses are similar to those of present star-forming regions, their…

Understanding the formation of the first stars is one of the frontier topics in modern astrophysics and cosmology. Their emergence signaled the end of the cosmic dark ages, a few hundred million years after the Big Bang, leading to a…

The first stars are assumed to be predominantly massive. Although, due to the low initial abundances of heavy elements the line-driven stellar winds are supposed to be inefficient in the first stars, these stars may loose a significant…

We review recent theoretical results on the formation of the first stars in the universe, and emphasize related open questions. In particular, we discuss the initial conditions for Population III star formation, as given by variants of the…

Motivated by theoretical predictions that first stars were predominantly very massive, we investigate the physics of the transition from an early epoch dominated by massive Pop III stars to a later epoch dominated by familiar low-mass Pop…

Star formation rates (SFR) larger than 1000 Msun/ yr are observed in extreme star bursts. This leads to the formation of star clusters with masses > 10^6 Msun in which crowding of the pre-stellar cores may lead to a change of the stellar…

The formation of the first generations of stars at redshifts z > 15-20 signaled the transition from the simple initial state of the universe to one of increasing complexity. We here review recent progress in understanding the assembly…