Related papers: Making a supermassive star by stellar bombardment
Motivated by JWST observations of dense, clumpy and clustered high redshift star formation, we simulate the hierarchical assembly of nine $M_{\mathrm{cl}}=10^6 M_\odot$ star clusters using the BIFROST N-body code. Our low metallicity models…
The origins and mergers of supermassive black holes (BHs) remain a mystery. We describe a scenario from a novel multi-physics simulation featuring rapid ($\lesssim 1\,$Myr) hyper-Eddington gas capture by a $\sim 1000\,{\rm M}_{\odot}$…
We present direct N-body simulations, carried out with Nbody6++GPU, of young and compact low metallicity star clusters with $1.1\times 10^5$ stars, a velocity dispersion of $\sim$ 10 $\mathrm{km\,s^{-1}}$, a half mass radius $R_h=0.6$ pc,…
Most stellar evolution models predict that black holes (BHs) should not exist above approximately $50-70$ M$_\odot$, the lower limit of the pair-instability mass gap. However, recent LIGO/Virgo detections indicate the existence of BHs with…
We use direct N-body simulations of gas embedded star clusters to study the importance of stellar collisions for the formation and mass accretion history of high-mass stars. Our clusters start in virial equilibrium as a mix of gas and…
Dense stellar environments like nuclear star clusters (NSCs) can dynamically assemble gravitational wave (GW) sources. We consider a population of single stellar mass black holes (BHs) in the inner $0.1$~pc of a NSC surrounding a $4 \times…
Intermediate mass black holes (IMBHs) in the mass range $10^2-10^5\,\mathrm{M_{\odot}}$ bridge the gap between stellar black holes (BHs) and supermassive BHs. Here, we investigate the possibility that IMBHs form in young star clusters via…
The study of galaxy mergers and supermassive binary black holes (SMBBHs) is central to our understanding of the galaxy and black hole assembly and (co-)evolution at the epoch of structure formation and throughout cosmic history. Galaxy…
The existence of $\approx$10^9 Msun supermassive black holes (SMBHs) within the first billion year of the universe has stimulated numerous ideas for the prompt formation and rapid growth of BHs in the early universe. Here we review ways in…
We estimate the rate at which stars are captured by supermassive black holes (BHs) in the centres of bulges and elliptical galaxies assuming that these initially had an isothermal cusp (rho ~ r^{-2} with velocity dispersion sigma_*). If…
We develop a model for galaxy formation and the growth of supermassive black holes (SMBHs), based on the fact that cold dark matter (CDM) halos form their gravitational potential wells through a fast phase with rapid change in the…
Context. We present simulations of a massive young star cluster using \textsc{Nbody6++GPU} and \textsc{MOCCA}. The cluster is initially more compact than previously published models, with one million stars, a total mass of $5.86 \times…
We propose a new mechanism for the growth of supermassive black hole (BH) seeds in the star-forming progenitors of local early-type galaxies (ETGs) at $z\gtrsim 1$. This envisages the migration and merging of stellar compact remnants…
Recent observations of short gamma-ray bursts (SGRBs) suggest that binary neutron star (NS) mergers can create highly magnetised, millisecond NSs. Sharp cut-offs in X-ray afterglow plateaus of some SGRBs hint at the gravitational collapse…
We consider a scenario where supermassive black holes form through direct accumulation of gas at the centre of proto-galaxies. In the first stage, the accumulated gas forms a super-massive star whose core collapses when the nuclear fuel is…
The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the…
In many galactic nuclei, a nuclear stellar cluster (NSC) co-exists with a supermassive black hole (SMBH). In this work, we explore the idea that the NSC forms before the SMBH through the merger of several stellar clusters that may contain…
We numerically investigate dynamical and chemical properties of star clusters (open and globular clusters, and ``super star clusters'', SSC) formed in interacting/merging galaxies. The investigation is two-fold: (1) large-scale…
We study the growth rate of stars via stellar collisions in dense star clusters, calibrating our analytic calculations with direct N-body simulations of up to 65536 stars, performed on the GRAPE family of special-purpose computers. We find…
The rapid emergence of supermassive black holes (SMBHs) in the early Universe poses a challenge to current models of black hole growth. One promising formation pathway is the direct collapse black hole (DCBH) scenario, in which gas in…