Search Publications
The JWST Resolved Stellar Populations Early Release Science Program. VI. Identifying Evolved Stars in Nearby Galaxies
Gennaro, Mario; McQuinn, Kristen B. W.; Dolphin, Andrew E. +20 more
We present an investigation of evolved stars in the nearby star-forming galaxy Wolf–Lundmark–Melotte (WLM), using Near-Infrared Camera (NIRCam) imaging from the JWST Resolved Stellar Populations Early Release Science program. We find that various combinations of the F090W, F150W, F250M, and F430M filters can effectively isolate red supergiants and…
JWST Imaging of the Closest Globular Clusters. II. Discovery of Brown Dwarfs in NGC 6397 and Measurement of Age from the Brown Dwarf Cooling Sequence, Using SANDee—A New Grid of Model Isochrones across the Hydrogen-burning Limit
Anderson, Jay; Burgasser, Adam J.; Bedin, Luigi R. +4 more
Globular clusters contain vast repositories of metal-poor stars that represent some of the oldest stellar generations in the Universe. The archaeological footprint of early Galactic evolution may be retained in the measurable properties of globular clusters, such as their ages, mass functions, and chemical abundances. Until recently, all photometr…
Observations of the 2022 September 5 Solar Energetic Particle Event at 15 Solar Radii
Mitchell, D. G.; McComas, D. J.; Bale, S. D. +27 more
On 2022 September 5, Parker Solar Probe (Parker) observed a large solar energetic particle (SEP) event at the unprecedented distance of only 15 R S from the Sun. The observations from the Integrated Science Investigation of the Sun (IS⊙IS) obtained over the course of this event are remarkably rich, and an overview is presented here. IS⊙…
Observations of Extremely Metal-poor O Stars: Weak Winds and Constraints for Evolution Models
McQuinn, Kristen B. W.; Chisholm, John; Berg, Danielle A. +3 more
Metal-poor massive stars drive the evolution of low-mass galaxies, both locally and at high redshift. However, quantifying the feedback they impart to their local surroundings remains uncertain because models of stellar evolution, mass loss, and ionizing spectra are unconstrained by observations below 20% solar metallicity (Z ⊙). We pre…
JWST/NIRCam 4–5 µm Imaging of the Giant Planet AF Lep b
Salama, Maïssa; Perrin, Marshall D.; Pueyo, Laurent +23 more
With a dynamical mass of 3 M Jup, the recently discovered giant planet AF Lep b is the lowest-mass imaged planet with a direct mass measurement. Its youth and spectral type near the L/T transition make it a promising target to study the impact of clouds and atmospheric chemistry at low surface gravities. In this work, we present JWST/NI…
CLASSY. IX. The Chemical Evolution of the Ne, S, Cl, and Ar Elements
Ravindranath, Swara; Martin, Crystal L.; Kumari, Nimisha +20 more
To study the chemical evolution across cosmic epochs, we investigate Ne, S, Cl, and Ar abundance patterns in the Cosmic Origins Spectrograph Legacy Archive Spectroscopic SurveY (CLASSY). CLASSY comprises local star-forming galaxies (SFGs; 0.02 < z < 0.18) with enhanced star formation rates, making them strong analogues to high-z SFGs. With d…
AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817
Gorjian, Varoujan; Kaspi, Shai; Hall, Patrick B. +49 more
We fit the UV/optical lightcurves of the Seyfert 1 galaxy Mrk 817 to produce maps of the accretion disk temperature fluctuations δ T resolved in time and radius. The δ T maps are dominated by coherent radial structures that move slowly (v ≪ c) inward and outward, which conflicts with the idea that disk variability is driven only by reverberation. …
Probing the Heights and Depths of Y Dwarf Atmospheres: A Retrieval Analysis of the JWST Spectral Energy Distribution of WISE J035934.06–540154.6
Cushing, Michael C.; Kirkpatrick, J. Davy; Marley, Mark S. +5 more
We present an atmospheric retrieval analysis of the Y0 brown dwarf WISE J035934.06‑540154.6 using the low-resolution 0.96–12 µm James Webb Space Telescope (JWST) spectrum presented in Beiler et al. We obtain volume number mixing ratios of the major gas-phase absorbers (H2O, CH4, CO, CO2, PH3, and H…
Strategies for Obtaining Robust Spectral Energy Distribution Fitting Parameters for Galaxies at z ∼ 1 and z ∼ 2 in the Absence of Infrared Data
Salim, Samir; Osborne, Chandler
Robust estimation of star formation rates (SFRs) at higher redshifts (z ≳ 1) using UV–optical–near-infrared (NIR) photometry is contingent on the ability of spectral energy distribution (SED) fitting to constrain the dust attenuation, stellar metallicity, and star formation history (SFH) simultaneously. IR-derived dust luminosities can help break …
Discovery of Optically Emitting Circumgalactic Nebulae around the Majority of UV-luminous Quasars at Intermediate Redshift
Contini, Thierry; Johnson, Sean D.; Petitjean, Patrick +15 more
We report the discovery of large, ionized, [O II]-emitting circumgalactic nebulae around the majority of 30 UV-luminous quasars at z = 0.4–1.4 observed with deep, wide-field integral field spectroscopy with the Multi-Unit Spectroscopy Explorer (MUSE) by the Cosmic Ultraviolet Baryon Survey and MUSE Quasar Blind Emitters Survey. Among the 30 quasar…