Related papers: The Impossibly Early Galaxy Problem
According to the hierarchical scenario, galaxies form via merging and accretion of small objects. Using N-body simulations, we study the frequency of merging events in the history of the halos. We find that at z<~2 the merging rate of the…
A standard paradigm is now available for the recent evolution (z < 10) of structure on galactic and larger scales. Most of the matter is assumed to be dark and dissipationless and to cluster hierarchically from gaussian initial conditions.…
Massive clusters of galaxies have been found as early as 3.9 Billion years (z=1.62) after the Big Bang containing stars that formed at even earlier epochs. Cosmological simulations using the current cold dark matter paradigm predict these…
The James Webb Space Telescope continues to push back the redshift frontier to ever earlier cosmic epochs, with recent announcements of galaxy candidates at redshifts of $15 \lesssim z \lesssim 30$. We leverage the recent GUREFT suite of…
We present an analysis of the evolution of 8625 Luminous Red Galaxies between z = 0.4 and z = 0.8 in the 2dF and SDSS LRG and QSO (2SLAQ) survey. The LRGs are split into redshift bins and the evolution of both the luminosity and stellar…
We study the formation of galaxies by using $N$-body/hydrodynamics simulations to investigate how baryons collect at the centre of dark matter halos. We treat the dark matter as a collisionless fluid and the baryons as an ideal gas. We…
We discuss on the early stage of galaxy formation based on recent deep surveys for very high-redshift galaxies, mostly beyond redshift of 6. These galaxies are observed to be strong Lyman$\alpha$ emitters, indicating bursts of massive star…
In hierarchical models of galaxy formation, ellipticals form from the merging of disk galaxies drawn together by gravity as their surrounding dark halos coalesce. Using semi-analytic techniques, we are able to follow the merging, star…
Hierarchical galaxy formation is the model whereby massive galaxies form from an assembly of smaller units. The most massive objects therefore form last. The model succeeds in describing the clustering of galaxies, but the evolutionary…
JWST has measured an unprecedented abundance of galaxies above $z\gtrsim 4-5$, whose formation and evolution are still difficult to reconcile within traditional galaxy evolution models in a $\Lambda$CDM framework. Here, we present a study…
Galaxy mass assembly is an end product of structure formation in the $\Lambda$CDM cosmology. As an extension of Lee \& Yi (2013), we investigate the assembly history of stellar components in galaxies as a function of halo environments and…
We have obtained deep, multi-band imaging observations around three of the most distant known quasars at redshifts z>6. Standard accretion theory predicts that the supermassive black holes present in these quasars were formed at a very…
We present a detailed investigation of the changing relationship between galaxies and the dark matter haloes they inhabit from z~1.2 to the present day. We do this by comparing precise galaxy clustering measurements over 133 deg2 of the…
The first galaxies formed at high redshifts, and were likely substantially less massive than typical galaxies in the local universe. We argue that (1) the reionization of a clumpy intergalactic medium by redshift z=6, (2) its enrichment by…
We use hydrodynamic simulations to examine how the baryonic components of galaxies are assembled, focusing on the relative importance of mergers and smooth accretion in the formation of ~L_* systems. In our primary simulation, which models…
About two-thirds of present-day, large galaxies are spirals such as the Milky Way or Andromeda, but the way their thin rotating disks formed remains uncertain. Observations have revealed that half of their progenitors, six billion years…
The abundance of galactic systems at high redshifts can impose a strong constraint on the cold+hot dark matter (CDM+HDM) models. The hot component reduces the excessive small-scale power in the COBE-normalized CDM model but also delays the…
We study the evolution of the global stellar mass density in a Lambda cold dark matter universe using two different types of hydrodynamical simulations (Eulerian TVD and SPH) and the analytical model of Hernquist & Springel (2003). We find…
Elliptical and S0 galaxies dominate the galaxy population in nearby rich clusters such as Coma. Studies of the evolution of the colors, M/L ratios, and line indices of early-type galaxies indicate that they have been a highly homogeneous,…
A new view on our Galaxy has recently emerged, with large consequences on its formation scenarios. Not only new dwarf satellites have been detected, still orbiting and tidally disrupting, but also a multitude of stellar streams or tidal…