ﻻ يوجد ملخص باللغة العربية
We use 25 simulated galaxies from the NIHAO project to define and characterize a variety of kinematic stellar structures: thin and thick discs, large scale single discs, classical and pseudo bulges, spheroids, inner discs, and stellar haloes. These structures have masses, spins, shapes and rotational support in good agreement with theoretical expectations and observational data. Above a dark matter halo mass of $2.5times10^{rm~11}M_{rmodot}$, all galaxies have a classical bulge and 70% have a thin and thick disc. The kinematic (thin) discs follow a power-law relation between angular momentum and stellar mass $J_{rm *}=3.4M_{rm *}^{rm1.26pm0.06}$, in very good agreement with the prediction based on the empirical stellar-to-halo mass relation in the same mass range, and show a strong correlation between maximum `observed rotation velocity and dark matter halo circular velocity $v_{rm c}=6.4v_{rm max}^{0.64pm0.04}$. Tracing back in time these structures progenitors, we find all to lose a fraction $1-f_j$ of their maximum angular momentum. Thin discs are significantly better at retaining their high-redshift spins ($f_jsim0.70$) than thick ones ($f_jsim0.40$). Stellar haloes have their progenitor baryons assembled the latest ($z_{rm~1/2}sim1.1$) and over the longest timescales ($tausim6.2$~Gyr), and have the smallest fraction of stars born in-situ ($f_{rm in-situ}=0.35pm0.14$). All other structures have $1.5lesssim z_{rm1/2}lesssim3$, $tau=4pm2$~Gyr and $f_{rm in-situ}gtrsim0.9$.
This series of papers aims at understanding the formation and evolution of non-barred disc galaxies. We use the new spectro-photometric decomposition code, C2D, to separate the spectral information of bulges and discs of a statistically representativ
We present a multi-component structural analysis of the internal structure of $1074$ high redshift massive galaxies at $1<z<3$ from the CANDELS HST Survey. In particular we examine galaxies best-fit by two structural components, and thus likely formi
Detailed studies of galaxy formation require clear definitions of the structural components of galaxies. Precisely defined components also enable better comparisons between observations and simulations. We use a subsample of eighteen cosmological zoo
We studied the chronology of galactic bulge and disc formation by analysing the relative contributions of these components to the B-band rest-frame luminosity density at different epochs. We present the first estimate of the evolution of the fraction
We examine the stellar haloes of the Auriga simulations, a suite of thirty cosmological magneto-hydrodynamical high-resolution simulations of Milky Way-mass galaxies performed with the moving-mesh code AREPO. We study halo global properties and radia