相关论文: Metallicity evolution of direct collapse black hol…
We explore the growth of super-massive black holes and host galaxy bulges in the galaxy population using the Millennium Run LCDM simulation coupled with a model of galaxy formation. We find that, if galaxy mergers are the primary drivers…
We investigate the star formation and chemical evolution in the early universe by considering the merging history of the Galaxy in the {\Lambda}CDM scenario according to the extended Press-Schechter theory. We give some possible constraints…
Sub-damped Lyman-alpha systems (sub-DLAs) have previously been found to exhibit a steeper metallicity evolution than the classical damped Lyman-alpha systems (DLAs), evolving to close to solar metallicity by z~1. From new high-resolution…
Observations of distant bright quasars suggest that billion solar mass supermassive black holes (SMBHs) were already in place less than a billion years after the Big Bang. Models in which light black hole seeds form by the collapse of…
JWST has revealed a large population of massive black holes (BHs) in the early Universe with unusual properties which mark them as distinct from low-redshift active galactic nuclei. Such findings have prompted the development of new models…
Long-duration gamma-ray bursts (GRBs) provide a premier tool for studying high-redshift star-forming galaxies thanks to their extreme brightness and association with massive stars. Here we use GRBs to study the galaxy mass-metallicity…
While the connection between massive stars and supernova explosions is well established observationally, the link between massive stars and black hole formation remains elusive. Some massive stars may collapse directly to black holes…
A crucial question in galaxy formation is what role new accretion has in star formation. Theoretical models have predicted a wide range of correlation strengths between halo accretion and galaxy star formation. Previously, we presented a…
In massive primordial galaxies, the gas may directly collapse and form a single central massive object if cooling is suppressed. Line cooling by molecular hydrogen can be suppressed in the presence of a strong soft-ultraviolet radiation…
We have followed the evolution of multi-mass star clusters containing massive central black holes by N-body simulations on the GRAPE6 computers of Tokyo University. We find a strong cluster expansion and significant structural changes of…
Utilizing a new, high mass resolution hydrodynamic simulation we compute the metallicity evolution of damped Lyman alpha systems (DLAs) and find a reasonable agreement with observations. In particular, the observed slow evolution of the DLA…
Hydrodynamic simulations of Lyman alpha clouds based on ab inito cosmological models have produced results that are in broad agreement with observations. However, further analyses have revealed that, with progressively higher numerical…
The dynamical processes involving stellar-remnant black holes (BH) in stellar clusters has always drawn attention due to the BHs' potential in a number of astrophysical phenomena, especially the dynamical formation of binary black holes…
The latest studies of massive star evolution indicate that an initially rapidly rotating star with sufficiently low metallicity can produce a rapidly rotating, massive stellar core that could be a progenitor of long-soft gamma-ray bursts…
With optical and near-infrared follow-up observations of gamma-ray bursts (GRBs) it is possible to study the chemical enrichment of galaxies at high redshift. Especially interesting are measurements of the metallicity of GRB host with…
Galactic nuclei host central massive objects either in the form of supermassive black holes or nuclear stellar clusters. Recent investigations have shown that both components co-exist in at least a few galaxies. In this paper we explore the…
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…
We have used Hubble Space Telescope Wide Field Planetary Camera 2 observations to construct a color-magnitude diagram (CMD) for the bulge of M31 at a location ~1.6 kpc from the galaxy's center. Using scaled-solar abundance theoretical red…
The possible formation of Direct Collapse Black Holes (DCBHs) in the first metal-free atomic cooling halos at high redshifts ($z > 10$) is nowadays object of intense study and several methods to prove their existence are currently under…
While large numbers of supermassive black holes have been detected at z>6, their origin is still essentially unclear. Numerical simulations have shown that the conditions for the classical direct collapse scenario are very restrictive and…