Related papers: The Cosmic Timeline Implied by the JWST High-redsh…
This paper highlights initial photometric analyses of JWST NIRCam imaging data in the sightline of SMACS0723, aiming to identify galaxies at redshift $z>7$. By applying a conservative Lyman-break selection followed by photometric redshift…
Recent observations with JWST have identified several bright galaxy candidates at $z\gtrsim 10$, some of which appear unusually massive (up to $\sim 10^{11}\ \rm M_{\odot}$). Such early formation of massive galaxies is difficult to…
Observations of large amount of massive galaxies with relatively old populations found at high redshifts are challenging galaxy formation scenarios within standard cosmology. Precise determinations of the average age of these galaxies would…
Cosmic chronometers offer a model-independent way to trace the expansion history of the Universe via the dating of passively evolving objects. This enables testing the validity of cosmological models without concrete assumptions of their…
Old high-$z$ galaxies are important tools for understanding the structure formation problem and may become the key to determine the ultimate fate of the Universe. In this {\it letter}, the inferred ages of the three oldest galaxies at high…
Here we present a sample of 12 massive quiescent galaxy candidates at z~3-4 observed with the James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec). These galaxies were pre-selected from the Hubble Space Telescope imaging…
The dramatic first images with James Webb Space Telescope (JWST) demonstrated its power to provide unprecedented spatial detail for galaxies in the high-redshift universe. Here, we leverage the resolution and depth of the JWST Cosmic…
We report ultra-deep, medium-resolution spectroscopic observations for 4 quiescent galaxies with log$_{10}(M_*/\mathrm{M_\odot})>11$ at $3 < z < 5$. These data were obtained with JWST NIRSpec as part of the Early eXtragalactic Continuum and…
The advent of the James Webb Space Telescope (JWST) signals a new era in exploring galaxies in the high-$z$ universe. Current and upcoming JWST imaging will potentially detect galaxies out to $z \sim 20$, creating a new urgency in the quest…
The existence of massive ($10^{11}$ solar masses) elliptical galaxies by redshift z~4 (when the Universe was 1.5 billion years old) necessitates the presence of galaxies with star-formation rates exceeding 100 solar masses per year at z>6…
We exploit James Webb Space Telescope (JWST) NIRCam observations from the GLASS-JWST-Early Release Science program to investigate galaxy stellar masses at z>7. We first show that JWST observations reduce the uncertainties on the stellar…
The standard model of cosmology has begun to show signs of internal inconsistencies under the relentless onslaught of precision data from the James Webb Telescope (JWST), the Hubble Telescope (HST) and other space-based observation…
Recent discoveries made with JWST observations include a significant number of barred galaxies at high redshift. Their origin remains unclear and their presence seems difficult to reproduce in cosmological simulations of galaxy formation…
The unexpectedly large abundance of UV-bright galaxies at $z>10$ discovered by the James Webb Space Telescope poses a significant challenge to the standard $\Lambda$CDM cosmology. This work tests whether modifying the cosmological…
The earliest JWST observations have revealed an unexpected abundance of super-early ($z>10$), massive ($M_*\approx 10^9\, M_\odot$) galaxies at the bright-end ($M_{\rm UV}\approx -21$) of the ultraviolet luminosity function (UV LF). We…
We have investigated the properties of a bright K-band selected sample of early-type galaxies in the Hubble Deep Field, as representative of the field galaxy population. This dataset is unique as for the morphological information on faint…
Observations suggest that high-redshift galaxies are either very dusty or essentially dust free. The evolution from one regime to the other must also be very fast, since evolved and dusty galaxies show up at redshifts corresponding to a…
Determining when the first galaxies formed remains an outstanding goal of modern observational astronomy. Theory and current stellar population models imply that the first galaxies formed at least at $z = 14-15$. But to date, only one…
We examine the assembly process and the observability of a first galaxy (M_vir~10^9 solar mass at z~8) with cosmological zoom-in, hydrodynamic simulations, including the radiative, mechanical, and chemical feedback exerted by the first…
Local and low-redshift ($z$<$3$) galaxies are known to broadly follow a bimodal distribution: actively star forming galaxies with relatively stable star-formation rates, and passive systems. These two populations are connected by galaxies…