Search Publications
No Top-heavy Stellar Initial Mass Function Needed: The Ionizing Radiation of GS9422 Can Be Powered by a Mixture of an Active Galactic Nucleus and Stars
Johnson, Benjamin D.; Tacchella, Sandro; Leja, Joel +2 more
JWST is producing high-quality rest-frame optical and UV spectra of faint galaxies at z > 4 for the first time, challenging models of galaxy and stellar populations. One galaxy recently observed at z = 5.943, GS9422, has nebular line and UV continuum emission that appears to require a high ionizing photon production efficiency. This has been ex…
The Extreme Low-mass End of the Mass–Metallicity Relation at z ∼ 7
Maseda, Michael V.; Labbé, Ivo; Nanayakkara, Themiya +17 more
The mass–metallicity relation provides crucial insights into the baryon cycle in galaxies and strong constraints on galaxy formation models. We use JWST NIRSpec observations from the UNCOVER program to measure the gas-phase metallicity in a sample of eight galaxies during the epoch of reionization at z = 6–8. Thanks to the strong lensing of the ga…
JWST Reveals Powerful Feedback from Radio Jets in a Massive Galaxy at z = 4.1
Pentericci, Laura; Heckman, Timothy; Bosman, Sarah E. I. +11 more
We report observations of a powerful ionized gas outflow in the z = 4.1 luminous radio galaxy TNJ1338-1942 hosting an obscured quasar using the Near Infrared Spectrograph (NIRSpec) on board JWST. We spatially resolve a large-scale (∼15 kpc) outflow and measure outflow rates. The outflowing gas shows velocities exceeding 900 km s‑1 and b…
The Star Formation Efficiency during Reionization as Inferred from the Hubble Frontier Fields
Lidz, Adam; Sipple, Jackson
A recent ultraviolet luminosity function (UVLF) analysis in the Hubble Frontier Fields, behind foreground lensing clusters, has helped solidify estimates of the faint-end of the z ~ 5-9 UVLF at up to 5 mag fainter than in the field. These measurements provide valuable information regarding the role of low-luminosity galaxies in reionizing the univ…
Self-interacting Dark Matter Interpretation of Crater II
Yang, Daneng; Yu, Hai-Bo; Zhang, Xingyu +1 more
The satellite galaxy Crater II of the Milky Way is extremely cold and exceptionally diffuse. These unusual properties are challenging to understand in the standard model of cold dark matter. We use controlled N-body simulations to investigate the formation of Crater II in self-interacting dark matter (SIDM), where dark matter particles can scatter…
High Hard X-Ray Polarization in Cygnus X-1 Confined to the Intermediate Hard State: Evidence for a Variable Jet Component
Rao, A. R.; Bhalerao, Varun; Mithun, N. P. S. +7 more
Cygnus X-1, the well-known accreting black hole system, exhibits several observational features hinting at an intricate interplay between the accretion disk, its atmosphere known as the corona, and the putative relativistic jet. It has been extensively studied using all available observational methods, including using the newly available technique…
The Dynamic, Chimeric Inner Disk of PDS 70
Banzatti, Andrea; Gaidos, Eric; Shappee, Benjamin J. +4 more
Transition disks, with inner regions depleted in dust and gas, could represent later stages of protoplanetary disk evolution when newly formed planets are emerging. The PDS 70 system has attracted particular interest because of the presence of two giant planets in orbits at tens of astronomical units within the inner disk cavity, at least one of w…
Precise Bolometric Luminosities and Effective Temperatures of 23 Late-T and Y Dwarfs Obtained with JWST
Cushing, Michael C.; Kirkpatrick, J. Davy; Marley, Mark S. +5 more
We present infrared spectral energy distributions of 23 late-type T and Y dwarfs obtained with the James Webb Space Telescope. The spectral energy distributions consist of NIRSpec PRISM and MIRI low-resolution spectrometer spectra covering the ∼1–12 µm wavelength range at λ/Δλ ≈ 100 and broadband photometry at 15, 18, and 21 µm. The sp…
The Metallicity Dependence of PAH Emission in Galaxies. I. Insights from Deep Radial Spitzer Spectroscopy
Skillman, Evan D.; Kennicutt, Robert C.; Dale, Daniel A. +9 more
We use deep Spitzer mid-infrared spectroscopic maps of radial strips across three nearby galaxies with well-studied metallicity gradients (M101, NGC 628, and NGC 2403) to explore the physical origins of the observed deficit of polycyclic aromatic hydrocarbons (PAHs) at subsolar metallicity (i.e., the PAH–metallicity relation or PZR). These maps al…
A Population of Short-duration Gamma-Ray Bursts with Dwarf Host Galaxies
Leja, Joel; Fong, Wen-fai; Nugent, Anya E. +3 more
We present a population of 11 of the faintest (>25.5 AB mag) short gamma-ray burst (GRB) host galaxies. We model their sparse available observations using the stellar population inference code Prospector-β and develop a novel implementation to incorporate the galaxy mass–radius relation. Assuming these hosts are randomly drawn from the galaxy p…