Search Publications
Ambient Column Densities of Highly Ionized Oxygen in Precipitation-limited Circumgalactic Media
Voit, G. Mark
Many of the baryons associated with a galaxy reside in its circumgalactic medium (CGM), in a diffuse volume-filling phase at roughly the virial temperature. Much of the oxygen produced over cosmic time by the galaxy’s stars also ends up there. The resulting absorption lines in the spectra of UV and X-ray background sources are powerful diagnostics…
Evidence for an Aspherical Population III Supernova Explosion Inferred from the Hyper-metal-poor Star HE 1327-2326
Placco, Vinicius M.; Tominaga, Nozomu; Nomoto, Ken'ichi +6 more
We present observational evidence that an aspherical supernova explosion could have occurred in the first stars in the early universe. Our results are based on the first determination of a Zn abundance in a Hubble Space Telescope/Cosmic Origins Spectrograph high-resolution UV spectrum of a hyper-metal-poor (HMP) star, HE 1327-2326, with {{[Fe/H]}}…
SI IV Resonance Line Emission during Solar Flares: Non-LTE, Nonequilibrium, Radiation Transfer Simulations
Kerr, Graham S.; Carlsson, Mats; Young, Peter R. +2 more
The Interface Region Imaging Spectrograph routinely observes the Si IV resonance lines. When analyzing quiescent observations of these lines, it has typically been assumed that they form under optically thin conditions. This is likely valid for the quiescent Sun, but this assumption has also been applied to the more extreme flaring scenario. We us…
The ALMA Spectroscopic Survey in the HUDF: Nature and Physical Properties of Gas-mass Selected Galaxies Using MUSE Spectroscopy
Carilli, Chris; Somerville, Rachel S.; Bacon, Roland +31 more
We discuss the nature and physical properties of gas-mass selected galaxies in the ALMA spectroscopic survey (ASPECS) of the Hubble Ultra Deep Field (HUDF). We capitalize on the deep optical integral-field spectroscopy from the Multi Unit Spectroscopic Explorer (MUSE) HUDF Survey and multiwavelength data to uniquely associate all 16 line emitters,…
Validation of the Alfvén Wave Solar Atmosphere Model (AWSoM) with Observations from the Low Corona to 1 au
van der Holst, Bart; Lamy, Philippe; Vásquez, Alberto M. +9 more
We perform a validation study of the latest version of the Alfvén Wave Solar atmosphere Model (AWSoM) within the Space Weather Modeling Framework. To do so, we compare the simulation results of the model with a comprehensive suite of observations for Carrington rotations representative of the solar minimum conditions extending from the solar coron…
Global 3D Hydrodynamic Modeling of In-transit Lyα Absorption of GJ 436b
Lammer, H.; Khodachenko, M. L.; Shaikhislamov, I. F. +5 more
Using a global 3D, fully self-consistent, multifluid hydrodynamic model, we simulate the escaping upper atmosphere of the warm Neptune GJ 436b, driven by the stellar X-ray and ultraviolet (XUV) radiation impact and gravitational forces and interacting with the stellar wind. Under the typical parameters of XUV flux and stellar wind plasma expected …
Morphologies of ∼190,000 Galaxies at z = 0-10 Revealed with HST Legacy Data. III. Continuum Profile and Size Evolution of Lyα Emitters
Ouchi, Masami; Harikane, Yuichi; Shibuya, Takatoshi +1 more
We present the redshift evolution of the radial surface brightness profile of the rest-frame UV and optical stellar continua for 9119 Lyα emitters (LAEs) at z ≃ 0-8 and 0-2, respectively. Using Hubble Space Telescope data and the LAE catalogs taken from the literature, we derive the structural quantities of the 9119 LAEs, and of ≃180,000 of photo-…
Confirming Herschel Candidate Protoclusters from ALMA/VLA CO Observations
Pérez-Fournon, I.; Valtchanov, I.; Clements, D. L. +11 more
ALMA 870 µm continuum imaging has uncovered a population of blends of multiple dusty star-forming galaxies (DSFGs) in sources originally detected with the Herschel Space Observatory. However, their pairwise separations are much smaller than what is found by ALMA follow-up of other single-dish surveys or expected from theoretical simulations.…
Weighing the Darkness: Astrometric Mass Measurement of Hidden Stellar Companions Using Gaia
Breivik, Katelyn; Andrews, Jeff J.; Chatterjee, Sourav
In astrometric binaries, the presence of a dark, unseen star can be inferred from the gravitational pull it induces on its luminous binary companion. While the orbit of such binaries can be characterized with precise astrometric measurements, constraints made from astrometry alone are not enough to measure the component masses. In this work, we de…
Discovery of Highly Blueshifted Broad Balmer and Metastable Helium Absorption Lines in a Tidal Disruption Event
Cenko, S. B.; Veilleux, S.; Foley, Ryan J. +25 more
We report the discovery of nonstellar hydrogen Balmer and metastable helium absorption lines accompanying a transient, high-velocity (0.05c) broad absorption line (BAL) system in the optical spectra of the tidal disruption event (TDE) AT2018zr (z = 0.071). In the Hubble Space Telescope UV spectra, absorption of high- and low-ionization lines is al…