Related papers: Explaining the "too massive" high-redshift galaxie…
Recent findings from photometric and spectroscopic JWST surveys have identified examples of high-redshift galaxies at $z \gtrsim 10$. These high-$z$ galaxies appear to form much earlier and exhibit greater UV luminosity than predicted by…
JWST observations have revealed that massive galaxies formed and evolved far faster than predicted by galaxy formation models, with many having already assembled a large mass in stars $\sim12$ billion years ago [1-7]. However, masses of…
The observed rest-UV luminosity function at cosmic dawn ($z \sim 8-14$) measured by JWST revealed an excess of UV-luminous galaxies relative to many pre-launch theoretical predictions. A high star-formation efficiency (SFE) and a top-heavy…
Early results from the James Webb Space Telescope (JWST) observations have hinted at two traces beyond the standard cosmological framework. One is the extraordinarily high stellar masses and their density at $z=7.5\sim9.1$, another is the…
The James Webb Space Telescope (JWST) has unveiled unexpectedly massive galaxy candidates at high redshifts, challenging standard $\Lambda$CDM cosmological predictions. In this work, we study the predictions of more realistic dark matter…
The detection of numerous and relatively bright galaxies at redshifts z > 9 has prompted new investigations into the star-forming properties of high-redshift galaxies. Using local forms of the initial mass function (IMF) to estimate stellar…
Early JWST observations have revealed substantial numbers of galaxies out to redshifts as high as $z \simeq 14$, reflecting a slow evolution of the galaxy UV luminosity function (LF) not anticipated by many models of galaxy evolution. The…
The James Webb Space Telescope (JWST) has recently conducted observations of massive galaxies at high redshifts, revealing a notable anomaly in their star formation efficiency (SFE). Motivated by the recent identification of three $\sim…
The James Webb Space Telescope (JWST) has uncovered an abundance of $z>10$ galaxies bright in the ultraviolet (UV) that has challenged traditional theoretical models at high redshifts. Recently, various new models have emerged to address…
The discovery of massive, high redshift galaxies with the James Webb Space Telescope (JWST) has been argued to challenge $\Lambda$CDM (cold dark matter): such systems would require extremely rare halos and baryon-to-stellar-mass conversion…
The James Webb Space Telescope (JWST) has unveiled a population of unexpectedly massive and luminous galaxies at redshifts $z \gtrsim 7$, posing a significant challenge to the standard $\Lambda$CDM cosmological paradigm. In this work, we…
One of the primary goals for the upcoming James Webb Space Telescope (JWST) is to observe the first galaxies. Predictions for planned and proposed surveys have typically focused on average galaxy counts, assuming a random distribution of…
The field of high redshift galaxy formation has been revolutionised by JWST, which is yielding unprecedented insights on galaxy assembly at early times. Our key aim is to study the physical mechanisms that can explain the unexpected…
Early observations with JWST have led to the discovery of an unexpected large density (stellar mass density $\rho_*\approx 10^{6}\,M_{\odot}\,Mpc^{-3}$) of massive galaxies (stellar masses $M_*\geq 10^{10.5}M_{\odot}$) at extremely high…
Detection of the radiation emitted from the first galaxies at z > 10 will be made possible in the next decade, with the launch of the James Webb Space Telescope (JWST). We carry out cosmological radiation hydrodynamics simulations of…
Recent observations by the James Webb Space Telescope have revealed massive galaxies at very high redshift ($z\simeq 7-15$). The question of whether the existence of such galaxies is expected in the corresponding JWST surveys has received a…
JWST observations have revealed an overabundance of bright galaxies at $z \geq 9$, creating apparent tensions with theoretical predictions within standard $\Lambda$CDM cosmology. We address this challenge using a semi-empirical approach…
Recent estimates point to abundances of z > 4 sub-millimeter (sub-mm) galaxies far above model predictions. The matter is still debated. According to some analyses the excess may be substantially lower than initially thought and perhaps…
It has frequently been suggested that the stellar IMF in galaxies was top-heavy at early times. This would be plausible physically if the IMF depends on a mass scale such as the Jeans mass that was higher at earlier times because of the…
Early observations with JWST indicate an over-abundance of bright galaxies at redshifts $z \gtrsim 10$ relative to Hubble-calibrated model predictions. More puzzling still is the apparent lack of evolution in the abundance of such objects…