Search Publications
Exploring the nature of UV-bright z ≳ 10 galaxies detected by JWST: star formation, black hole accretion, or a non-universal IMF?
Graziani, Luca; Schneider, Raffaella; Chon, Sunmyon +4 more
We use the Cosmic Archaeology Tool (CAT) semi-analytical model to explore the contribution of Population (Pop) III/II stars and active galactic nuclei (AGNs) to the galaxy ultraviolet (UV) luminosity function (LF) evolution at 4 ≤ z ≤ 20. We compare in particular with recent JWST data in order to explore the apparent tension between observations a…
Deep Synoptic Array Science: First FRB and Host Galaxy Catalog
Hallinan, Gregg; Hodges, Mark; Lamb, James W. +19 more
Fast radio bursts (FRBs) are a powerful and mysterious new class of transients that are luminous enough to be detected at cosmological distances. By associating FRBs to host galaxies, we can measure intrinsic and environmental properties that test FRB origin models, in addition to using them as precise probes of distant cosmic gas. The Deep Synopt…
Active Galactic Nuclei Selection and Demographics: A New Age with JWST/MIRI
Pérez-González, Pablo G.; Bunker, Andrew J.; Scholtz, Jan +19 more
Understanding the coevolution of supermassive black holes and their host systems requires a comprehensive census of active galactic nuclei (AGNs) behavior across a wide range of redshift, luminosity, obscuration level, and galaxy properties. We report significant progress with JWST toward this goal from the Systematic Mid-infrared Instrument Legac…
Extreme N-emitters at high redshift: Possible signatures of supermassive stars and globular cluster or black hole formation in action
Schaerer, D.; Marques-Chaves, R.; Brammer, G. +9 more
Context. Recent James Webb Space Telescope (JWST) spectroscopic observations of the z = 10.6 galaxy GN-z11 have revealed a very peculiar UV spectrum exhibiting intense emission lines of nitrogen, which are not typically detected in galaxy spectra. This observation indicates a super-solar N/O abundance ratio at low metallicity, which only resembles…
JWST Observations Reject Unrecognized Crowding of Cepheid Photometry as an Explanation for the Hubble Tension at 8σ Confidence
Casertano, Stefano; Dolphin, Andrew; Riess, Adam G. +7 more
We present high-definition observations with the James Webb Space Telescope (JWST) of >1000 Cepheids in a geometric anchor of the distance ladder, NGC 4258, and in five hosts of eight Type Ia supernovae, a far greater sample than previous studies with JWST. These galaxies individually contain the largest samples of Cepheids, an average of >1…
Deciphering the JWST spectrum of a 'little red dot' at z ∼ 4.53: An obscured AGN and its star-forming host
Heintz, Kasper E.; Brammer, Gabriel; Coe, Dan +10 more
JWST has revealed a class of numerous, extremely compact sources with rest-frame red optical/near-infrared (NIR) and blue ultraviolet (UV) colours nicknamed 'little red dots'. We present one of the highest signal-to-noise ratio JWST NIRSpec prism spectra of a little red dot, J0647_1045 at z = 4.5319 ± 0.0001, and examine its NIRCam morphology to d…
Reionization after JWST: a photon budget crisis?
Chisholm, John; Mason, Charlotte; Furlanetto, Steven R. +2 more
New JWST observations are revealing the first galaxies to be prolific producers of ionizing photons, which we argue gives rise to a tension between different probes of reionization. Over the last two decades, a consensus has emerged where star-forming galaxies are able to generate enough photons to drive reionization, given reasonable values for t…
The complex circumstellar environment of supernova 2023ixf
Sollerman, J.; Bloom, J. S.; Gal-Yam, A. +54 more
The early evolution of a supernova (SN) can reveal information about the environment and the progenitor star. When a star explodes in vacuum, the first photons to escape from its surface appear as a brief, hours-long shock-breakout flare1,2, followed by a cooling phase of emission. However, for stars exploding within a distribution of d…
SPT clusters with DES and HST weak lensing. II. Cosmological constraints from the abundance of massive halos
Sharon, K.; Gladders, M. D.; Ade, P. A. R. +195 more
We present cosmological constraints from the abundance of galaxy clusters selected via the thermal Sunyaev-Zel'dovich (SZ) effect in South Pole Telescope (SPT) data with a simultaneous mass calibration using weak gravitational lensing data from the Dark Energy Survey (DES) and the Hubble Space Telescope (HST). The cluster sample is constructed fro…
Formation of a low-mass galaxy from star clusters in a 600-million-year-old Universe
Ravindranath, Swara; Rihtaršič, Gregor; Bradač, Maruša +19 more
The most distant galaxies detected were seen when the Universe was a scant 5% of its current age. At these times, progenitors of galaxies such as the Milky Way were about 10,000 times less massive. Using the James Webb Space Telescope (JWST) combined with magnification from gravitational lensing, these low-mass galaxies can not only be detected bu…