Search Publications
GA-NIFS: A massive black hole in a low-metallicity AGN at z ∼ 5.55 revealed by JWST/NIRSpec IFS
Pérez-González, Pablo G.; Charlot, Stéphane; Carniani, Stefano +20 more
We present rest-frame optical data of the compact z = 5.55 galaxy GS_3073 obtained using the integral field spectroscopy mode of the Near-InfraRed Spectrograph on board the James Webb Space Telescope. The galaxy's prominent broad components in several hydrogen and helium lines (though absent in the forbidden lines) and v detection of a large equiv…
Revealing galaxy candidates out to z 16 with JWST observations of the lensing cluster SMACS0723
Charlot, Stéphane; Chevallard, Jacopo; Mahler, Guillaume +8 more
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, we report the discovery of two galaxy candidates at z ~ 16, only 250 million years after the big bang. We al…
COSMOS-Web: An Overview of the JWST Cosmic Origins Survey
Finkelstein, Steven L.; Bagley, Micaela B.; Casey, Caitlin M. +83 more
We present the survey design, implementation, and outlook for COSMOS-Web, a 255 hr treasury program conducted by the James Webb Space Telescope in its first cycle of observations. COSMOS-Web is a contiguous 0.54 deg2 NIRCam imaging survey in four filters (F115W, F150W, F277W, and F444W) that will reach 5σ point-source depths ranging ~27…
Confirmation and refutation of very luminous galaxies in the early Universe
Papovich, Casey; Finkelstein, Steven L.; Buat, Véronique +34 more
During the first 500 million years of cosmic history, the first stars and galaxies formed, seeding the Universe with heavy elements and eventually reionizing the intergalactic medium1-3. Observations with the James Webb Space Telescope (JWST) have uncovered a surprisingly high abundance of candidates for early star-forming galaxies, wit…
A JWST/NIRCam study of key contributors to reionization: the star-forming and ionizing properties of UV-faint z 7-8 galaxies
Charlot, Stéphane; Chisholm, John; Chen, Zuyi +5 more
Spitzer/Infrared Array Camera (IRAC) imaging has revealed that the brightest z ~ 7-8 galaxies often exhibit young ages and strong nebular line emission, hinting at high ionizing efficiency among early galaxies. However, IRAC's limited sensitivity has long hindered efforts to study the fainter, more numerous population often thought largely respons…
Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM
Zhang, X.; Heng, K.; May, E. M. +91 more
Transmission spectroscopy1-3 of exoplanets has revealed signatures of water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations' relatively narrow wavelength range and spectral resolving po…
An Ice Age JWST inventory of dense molecular cloud ices
Egami, E.; McGuire, Brett A.; Sun, Fengwu +39 more
Icy grain mantles are the main reservoir of the volatile elements that link chemical processes in dark, interstellar clouds with the formation of planets and the composition of their atmospheres. The initial ice composition is set in the cold, dense parts of molecular clouds, before the onset of star formation. With the exquisite sensitivity of th…
The DESI Bright Galaxy Survey: Final Target Selection, Design, and Validation
Myers, Adam D.; Bailey, Stephen; Palanque-Delabrouille, Nathalie +57 more
Over the next 5 yr, the Dark Energy Spectroscopic Instrument (DESI) will use 10 spectrographs with 5000 fibers on the 4 m Mayall Telescope at Kitt Peak National Observatory to conduct the first Stage IV dark energy galaxy survey. At z < 0.6, the DESI Bright Galaxy Survey (BGS) will produce the most detailed map of the universe during the dark-e…
Gaia Data Release 3. Analysis of RVS spectra using the General Stellar Parametriser from spectroscopy
Hatzidimitriou, D.; Schultheis, M.; Marshall, D. J. +77 more
Context. The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution of stars and of Galactic stellar populations. A worldwide observational effort from the ground has provided, in one century, an extremely heterogeneous collection of chemical abundances for about two million stars in total, with f…
The brightest galaxies at cosmic dawn
Treu, Tommaso; Trenti, Michele; Mason, Charlotte A.
Recent JWST observations suggest an excess of z ≳ 10 galaxy candidates above most theoretical models. Here, we explore how the interplay between halo formation time-scales, star formation efficiency, and dust attenuation affects the properties and number densities of galaxies observed in the early Universe. To guide intuition, we calculate the the…