Related papers: Modeling Angular-Momentum History in Dark-Matter H…
A halo merger tree forms the essential backbone of a semi-analytic model for galaxy formation and evolution. Recent studies have pointed out that extracting merger trees from numerical simulations of structure formation is non-trivial;…
Both simulation and observational data have shown that the spin and shape of dark matter halos are correlated with their nearby large-scale environment. As structure formation on different scales is strongly coupled, it is trick to…
We use high-resolution numerical simulations to study the physical properties of subhalos when they merge into their host halos. An improved algorithm is used to identify the subhalos. We then examine their spatial and velocity…
For idealized (spherical, smooth) dark matter halos described by single-parameter density profiles (such as the NFW profile) there exists a one-to-one mapping between the energy of the halo and the scale radius of its density profile. The…
This paper presents a study of the specific merger rate as a function of group membership, local environment, and redshift in a very large, $500h^{-1} Mpc$, cosmological N-body simulation, the \textit{Millennium Simulation}. The goal is to…
We investigate the spin alignment of the dark matter halos by considering a mechanism somewhat similar to tidal locking. We dubbed it Tidal Locking Theory (TLT). While Tidal Torque Theory is responsible for the initial angular momentum of…
We present that the spin$-$orbit alignment (SOA; i.e., the angular alignment between the spin vector of a halo and the orbital angular momentum vector of its neighbor) provides an important clue to how galactic angular momenta develop. In…
We build a model to predict from first principles the properties of major mergers. We predict these from the coalescence of peaks and saddle points in the vicinity of a given larger peak, as one increases the smoothing scale in the initial…
We revisit the question of what mechanism is responsible for the spins of halos of dark matter. The answer to this question is of high importance for modeling galaxy intrinsic alignment, which can potentially contaminate current and future…
Spherical density profiles and specific angular momentum profiles of Dark Matter halos found in cosmological N-body simulations have been measured extensively. The distribution of the total angular momentum of dark matter halos is also used…
The spin, $\lambda$, of dark matter (DM) halos in cosmological simulations follows a log normal distribution and has little correlation with galaxy observables. As such, there is currently no way to infer the $\lambda$ parameter of…
Using a series of high-resolution N-body simulations of the concordance cosmology we investigate how the formation histories, shapes and angular momenta of dark-matter haloes depend on environment. We first present a classification scheme…
We investigate angular momentum acquisition in Milky Way-sized galaxies by comparing five high resolution zoom-in simulations, each implementing identical cosmological initial conditions, but utilizing different hydrodynamic codes: Enzo,…
We present a model for the dynamical evolution of subhaloes based on an approach combining numerical and analytical methods. Our method is based on tracking subhaloes in an N-body simulation up to the last point that it can be resolved, and…
We study how halo intrinsic dynamical properties are linked to their formation processes for halos in two mass ranges, $10^{12}-10^{12.5}h^{-1}{\rm M_\odot}$ and $\ge 10^{13}h^{-1}{\rm M_\odot}$, and how both are correlated with the large…
Semi-analytic models are best suited to compare galaxy formation and evolution theories with observations. These models rely heavily on halo merger trees, and their realistic features (i.e., no drastic changes on halo mass or jumps on…
The merging history of dark matter halos is computed with the Merging Cell Model proposed by Rodrigues & Thomas (1996). While originally discussed in the case of scale-free power spectra, it is developed and tested here in the framework of…
Halos and galaxies acquire their angular momentum during the collapse of surrounding large-scale structure. This process imprints alignments between galaxy spins and nearby filaments and sheets. Low mass halos grow by accretion onto…
Dark matter halo merger trees are now routinely extracted from cosmological simulations of structure formation. These trees are frequently used as inputs to semi-analytic models of galaxy formation to provide the backbone within which…
We construct merger trees from the largest database of dark matter haloes to date provided by the Millennium simulation to quantify the merger rates of haloes over a broad range of descendant halo mass (1e12 < M0 < 1e15 Msun), progenitor…