Search Publications
EMPRESS. XIV. Strong High-ionization Lines of Young Galaxies at z = 0–8: Ionizing Spectra Consistent with the Intermediate-mass Black Holes with M BH ∼ 103–106 M ⊙
Ono, Yoshiaki; Ouchi, Masami; Harikane, Yuichi +16 more
We present ionizing spectra estimated at 13.6–100 eV for 10 dwarf galaxies with strong high-ionization lines of He II λ4686 and [Ne V] λ3426 ([Ne IV] λ2424) at z = 0 (z = 8) that are identified in our Keck/LRIS spectroscopy and the literature (the JWST Early Release Observations program). With the flux ratios of these high-ionization lines and >…
The TRGB-SBF Project. I. A Tip of the Red Giant Branch Distance to the Fornax Cluster with JWST
Anand, Gagandeep S.; Blakeslee, John P.; Tully, R. Brent +7 more
Differences between the local value of the Hubble constant measured via the distance ladder versus the value inferred from the cosmic microwave background with the assumption of the standard ΛCDM model have reached over 5σ significance. To determine if this discrepancy is due to new physics or more mundane systematic errors, it is essential to rem…
Delayed X-Ray Brightening Accompanied by Variable Ionized Absorption Following a Tidal Disruption Event
Yao, Y.; Wevers, T.; Tombesi, F. +4 more
Supermassive black holes can experience super-Eddington peak mass fallback rates following the tidal disruption of a star. The theoretical expectation is that part of the infalling material is expelled by means of an accretion disk wind, whose observational signature includes blueshifted absorption lines of highly ionized species in X-ray spectra.…
New Insights on the Accretion Properties of Class 0 Protostars from 2 µm Spectroscopy
Le Gouellec, Valentin J. M.; Hillenbrand, Lynne A.; Greene, Thomas P. +1 more
Sun-like stars are thought to accrete most of their final mass during the protostellar phase, during which the stellar embryo is surrounded by an infalling dense envelope. We present an analysis of 26 K-band spectra of Class 0 protostars, which are the youngest protostars. Of these, 18 are new observations made with the Keck MOSFIRE instrument. H …
Hints of a Sulfur-rich Atmosphere around the 1.6 R ⊕ Super-Earth L98-59 d from JWST NIRspec G395H Transmission Spectroscopy
Sing, David K.; Valenti, Jeff A.; Espinoza, Néstor +11 more
Detecting atmospheres around planets with a radius below 1.6 R ⊕, commonly referred to as rocky planets, has proven to be challenging. However, rocky planets orbiting M dwarfs are ideal candidates due to their favorable planet-to-star radius ratio. Here, we present one transit observation of the Super-Earth L98-59 d (1.58 R ⊕…
Not-so-little Red Dots: Two Massive and Dusty Starbursts at z ∼ 5–7 Pushing the Limits of Star Formation Discovered by JWST in the COSMOS-Web Survey
Casey, Caitlin M.; Kartaltepe, Jeyhan S.; Koekemoer, Anton M. +24 more
We present the properties of two candidate massive (M ⋆ ∼ 1011 M ⊙) and dusty (A v > 2.5 mag) galaxies at z = 5–7 in the first 0.28 deg2 of the COSMOS-Web survey. One object is spectroscopically confirmed at z spec = 5.051, while the other has a robust z phot = 6.7 ± 0…
The Geochemical Potential for Metabolic Processes on the Sub-Neptune Exoplanet K2-18b
Glein, Christopher R.
Quantifying disequilibria is important to understand whether an environment could be habitable. It has been proposed that the exoplanet K2-18b has a hydrogen-rich atmosphere and a water ocean, making it a "hycean world." The James Webb Space Telescope recently made measurements of methane, CO2, and possibly dimethyl sulfide (DMS) in the…
Atmospheric Retrievals Suggest the Presence of a Secondary Atmosphere and Possible Sulfur Species on L98-59 d from JWST Nirspec G395H Transmission Spectroscopy
Sing, David K.; Espinoza, Néstor; Crouzet, Nicolas +10 more
L 98-59 d is a Super-Earth planet orbiting an M-type star. We performed retrievals on the transmission spectrum of L 98-59 d obtained using NIRSpec G395H during a single transit, from JWST Cycle 1 GTO 1224. The wavelength range of this spectrum allows us to detect the presence of several atmospheric species. We found that the spectrum is consisten…
PROJECT-J: JWST Observations of HH46 IRS and Its Outflow. Overview and First Results
Hartigan, Patrick; Codella, Claudio; Alcalá, Juan M. +23 more
We present the first results of the JWST program PROJECT-J (PROtostellar JEts Cradle Tested with JWST), designed to study the Class I source HH46 IRS and its outflow through NIRSpec and MIRI spectroscopy (1.66–28 µm). The data provide line images (∼6.″6 in length with NIRSpec, and up to ∼20″ with MIRI) revealing unprecedented details within …
Dissecting the Crab Nebula with JWST: Pulsar Wind, Dusty Filaments, and Ni/Fe Abundance Constraints on the Explosion Mechanism
Temim, Tea; Drissen, Laurent; Rest, Armin +19 more
We present JWST observations of the Crab Nebula, the iconic remnant of the historical SN 1054. The observations include NIRCam and MIRI imaging mosaics plus MIRI/MRS spectra that probe two select locations within the ejecta filaments. We derive a high-resolution map of dust emission and show that the grains are concentrated in the innermost, high-…