Related papers: First Light And Reionisation Epoch Simulations (FL…
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…
Early results from the JWST observations have reported a surprisingly high number of UV-bright galaxies at $z \geq 10$, which appears to challenge the theoretical predictions from standard galaxy formation models in the $\Lambda$CDM…
The James Webb Space Telescope (JWST) is capable of probing extremely early eras of our Universe when the supersonic relative motions between dark matter and baryonic overdensities modulate structure formation ($z>\sim 10$). We study…
The first deep field images from the James Webb Space Telescope (JWST) of the galaxy cluster SMACS~J0723.3-7327 reveal a wealth of new lensed images at uncharted infrared wavelengths, with unprecedented depth and resolution. Here we…
The selection of high-redshift galaxies often involves spectral energy distribution (SED) fitting to photometric data, an expectation for contamination levels, and measurement of sample completeness -- all vetted through comparison to…
I present written notes from three lectures given at the 54th Saas-Fee Advanced Course of the Swiss Society of Astrophysics and Astronomy in January 2025 entitled "Galaxies and Black Holes in the First Billion Years as seen by the JWST". I…
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…
High-redshift protoclusters are crucial for understanding the formation of galaxy clusters and the evolution of galaxies in dense environments. The James Webb Space Telescope (JWST), with its unprecedented near-infrared sensitivity, enables…
Next generation telescopes such as the James Webb Space Telescope (JWST) and the Nancy Grace Roman Space Telescope (NGRST) will enable us to study the first billion years of our Universe in unprecedented detail. In this work we use the…
The overabundance of super-early (redshift $z>10$), luminous ($M_{\rm UV} < -20$), and blue galaxies detected by JWST has been explained (Ferrara et al. 2023) as due to negligible dust attenuation in these systems. We show that such model…
The James Webb Space Telescope (JWST) is revolutionizing our understanding of the Universe by unveiling faint, near-infrared dropouts previously beyond our reach, ranging from exceptionally dusty sources to galaxies up to redshift $z \sim…
JWST observations of high redshift galaxies are used to measure their star formation histories - the buildup of stellar mass in the earliest galaxies. Here we use a novel analysis program, SEDz*, to compare near-IR spectral energy…
One of the main goals of the JWST is to study the first galaxies in the Universe. We present a systematic photometric analysis of very distant galaxies in the first JWST deep field towards the massive lensing cluster SMACS0723. As a result,…
Lyman $\alpha$ (Ly$\alpha$) emission is one of few observable features of galaxies that can trace the neutral hydrogen content in the Universe during the Epoch of Reionization (EoR). To accomplish this we need an efficient way to survey for…
Recent JWST observations with superb angular resolution have revealed the existence of clumpy galaxies at high redshift through the detection of rest-frame optical emission lines. We use the FirstLight simulation to study the properties of…
Empirical studies of the first generation of stars and quasars in the Universe will likely become feasible over the next decade. The Next Generation Space Telescope will provide direct imaging and photometry of sub-galactic objects at…
We present our lens mass model of SMACS J0723, the first strong gravitational lens observed by the James Webb Space Telescope (JWST). We use data from the Hubble Space Telescope and Multi Unit Spectroscopic Explorer (MUSE) to build our…
A substantial number of ultra-high redshift (8 < z < 17) galaxy candidates have been detected with JWST, posing the question: are these observational results surprising in the context of current galaxy formation models? We address this…
The wavelength-coverage and sensitivity of JWST now enables us to probe the rest-frame UV - optical spectral energy distributions (SEDs) of galaxies at high-redshift ($z>4$). From these SEDs it is, in principle, through SED fitting possible…
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…