Related papers: Age of massive galaxies at redshift 8

Recent studies have reported a non evolution of galaxy ages at redshifts higher than $z\sim$ 2.5, as well as galaxies older than the Universe. In this work, a sample of galaxies from JWST and HST was analysed via photometry to further…

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…

We have discovered a population of extremely red galaxies at $z\simeq 1.5$ which have apparent stellar ages of $\gs 3$ Gyr, based on detailed spectroscopy in the rest-frame ultraviolet. In order for galaxies to have existed at the high…

From James Webb Space Telescope (JWST) surveys, 31 galaxies with average redshift 7.3 are selected containing large Balmer break, Lyman-$\alpha$ break (V-shaped SED versus $\lambda$). Apart from Hubble Space Telescope (HST) and JWST-NIRCam…

We use very deep near-infrared photometry of the Hubble Deep Field South taken with ISAAC/VLT to identify a population of high redshift galaxies with rest- frame optical colors similar to those of nearby galaxies. The galaxies are chosen by…

Deep space observations of the James Webb Space Telescope (JWST) have revealed that the structure and masses of very early Universe galaxies at high redshifts (z~15), existing at ~0.3 Gyr after the BigBang, maybe as evolved as the galaxies…

As part of a larger program to identify and characterize possible low-redshift analogs to massive compact red galaxies found at high redshift, we have examined the morphologies of three low-redshift compact galaxies drawn from the sample of…

In the early Universe finding massive galaxies that have stopped forming stars present an observational challenge as their rest-frame ultraviolet emission is negligible and they can only be reliably identified by extremely deep…

We study the physical characteristics of galaxies at 6.3 < z < 8.6, selected from deep near-infrared imaging with the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. Accounting for the photometric scatter using simulations,…

Galaxies with stellar masses as high as $\sim 10^{11}$ solar masses have been identified out to redshifts $z \sim 6$, approximately one billion years after the Big Bang. It has been difficult to find massive galaxies at even earlier times,…

The first JWST data revealed an unexpected population of red galaxies that appear to have redshifts of $z\sim 7-9$ and high masses of $M_*$ $\sim$ 10$^{10}$ M$_{\odot}$ (Labb\'e et al. 2023). Here we fit S\'ersic profiles to the F200W…

In this invited talk I show how the reddest and rarest galaxies at high redshift ($z \simeq 1.5$) can be used to set the stellar evolution clock. I argue that one can confidently compute the collapse redshift of these objects. This yields…

The so-called `impossibly early galaxy' problem, first identified via the Hubble Space Telescope's observation of galaxies at redshifts z > 10, appears to have been exacerbated by the more recent James Webb Space Telescope (JWST) discovery…

Observations with the {\it James Webb Space Telescope} have revealed a high abundance of bright galaxies at redshift, $z\gtrsim 12$, which has been widely interpreted as conflicting with the $\Lambda$CDM model. In Cowley et al. (2018)…

Surveys with James Webb Space Telescope (JWST) have discovered candidate galaxies in the first 400 Myr of cosmic time. Preliminary indications have suggested these candidate galaxies may be more massive and abundant than previously thought.…

In their recent study, Labb\'e et al. used multi-band infrared images captured by the James Webb Space Telescope (JWST) to discover a population of red massive galaxies that formed approximately 600 million years after the Big Bang. The…

We present low-resolution near-infrared stacked spectra from the 3D-HST survey up to $z=2.0$ and fit them with commonly used stellar population synthesis models: BC03 (Bruzual & Charlot, 2003), FSPS10 (Flexible Stellar Population Synthesis,…

We present spectroscopic evidence from the Gemini Deep Deep Survey (GDDS) for a significant population of color-selected red galaxies at 1.3 < z < 2.2 whose integrated light is dominated by evolved stars. Unlike radio-selected objects, the…

We present a reduction and analysis of the \textit{James Webb Space Telescope} (JWST) SMACS~0723 field using new post-launch calibrations to conduct a search for ultra-high-redshift galaxies ($z > 9$) present within the Epoch of…

The most passive galaxies at high redshift are unlikely to be identified by either narrow-band emission-line searches, or by Lyman limit searches (both techniques which have been highlighted at this meeting) simply because such selection…