Search Publications
METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble Program. I. Overview and Initial Results
Jenkins, Edward B.; Yanchulova Merica-Jones, Petia; Meixner, Margaret +8 more
Metal Evolution, Transport, and Abundance in the LMC (METAL) is a large Cycle 24 program on the Hubble Space Telescope aimed at measuring dust extinction properties and interstellar depletions in the Large Magellanic Cloud (LMC) at half-solar metallicity. The 101-orbit program is composed of Cosmic Origins Spectrograph and Space Telescope Imaging …
Photochemical Hazes in Sub-Neptunian Atmospheres with a Focus on GJ 1214b
Showman, Adam P.; García Muñoz, Antonio; Steinrueck, Maria E. +2 more
We study the properties of photochemical hazes in super-Earth/mini-Neptune atmospheres with particular focus on GJ 1214b. We evaluate photochemical haze properties at different metallicities between solar and 10,000× solar. Within the four-order-of-magnitude change in metallicity, we find that the haze precursor mass fluxes change only by a factor…
The Sporadic Activity of (6478) Gault: A YORP-driven Event?
Wainscoat, Richard J.; Tonry, John; Ebeling, Harald +15 more
On 2019 January 5 a streamer associated with the 4-10 km main belt asteroid (6478) Gault was detected by the ATLAS sky survey, a rare discovery of activity around a main belt asteroid. Archival data from ATLAS and Pan-STARRS1 show the trail in early 2018 December, but not between 2010 and 2018 January. The feature has significantly changed over on…
Delayed Circumstellar Interaction for Type Ia SN 2015cp Revealed by an HST Ultraviolet Imaging Survey
Fox, O. D.; Smith, M.; Sullivan, M. +11 more
The nature and role of the binary companion of carbon-oxygen white dwarf stars that explode as Type Ia supernovae (SNe Ia) are not yet fully understood. Past detections of circumstellar material (CSM) that contain hydrogen for a small number of SN Ia progenitor systems suggest that at least some have a nondegenerate companion. In order to constrai…
Multiepoch Ultraviolet HST Observations of Accreting Low-mass Stars
Espaillat, Catherine C.; Robinson, Connor E.
Variability is a defining characteristic of young low-mass stars that are still accreting material from their primordial protoplanetary disk. Here we present the largest Hubble Space Telescope (HST) variability study of classical T Tauri stars (CTTS) to date. For five of these objects, we obtained a total of 25 spectra with the Space Telescope Ima…
Interstellar Medium and Star Formation of Starburst Galaxies on the Merger Sequence
Ho, Luis C.; Li, Zhihui; Zhuang, Ming-Yang +3 more
The interstellar medium is a key ingredient that governs star formation in galaxies. We present a detailed study of the infrared (∼1-500 µm) spectral energy distributions of a large sample of 193 nearby (z≲ 0.088) luminous infrared galaxies (LIRGs) covering a wide range of evolutionary stages along the merger sequence. The entire sample has …
The Far-infrared Polarization Spectrum of ρ Ophiuchi A from HAWC+/SOFIA Observations
Morris, Mark R.; Staguhn, Johannes; Ward-Thompson, Derek +23 more
We report on polarimetric maps made with HAWC+/SOFIA toward ρ Oph A, the densest portion of the ρ Ophiuchi molecular complex. We employed HAWC+ bands C (89 µm) and D (154 µm). The slope of the polarization spectrum was investigated by defining the quantity {{ \mathcal R }}{DC}={p}D/{p}C, where p C…
Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: GJ 832, GJ 176, and GJ 436
Peacock, Sarah; Barman, Travis; Baron, E. +3 more
Correct estimates of stellar extreme ultraviolet (EUV; 100-1170 Å) flux are important for studying the photochemistry and stability of exoplanet atmospheres, as EUV radiation ionizes hydrogen and contributes to the heating, expansion, and potential escape of a planet’s upper atmosphere. Contamination from interstellar hydrogen makes observing EUV …
Resolved Neutral Carbon Emission in Nearby Galaxies: [C I] Lines as Total Molecular Gas Tracers
Tan, Qinghua; Salak, Dragan; Gao, Yu +6 more
We present maps of atomic carbon [C I]({}3{{{P}}}1\to {{}3{{P}}}0) and [C I]({}3{{{P}}}2\to {{}3{{P}}}1) emission (hereafter [C I] (1-0) and [C I] (2-1), respectively) at a linear resolution ∼1 kpc scale for a sample of one H II, six LINER, three Seyfert, and f…
Crossing the Line: Active Galactic Nuclei in the Star-forming Region of the BPT Diagram
Salim, Samir; Agostino, Christopher J.
In this work, we investigate the reliability of the BPT diagram for excluding galaxies that host an active galactic nucleus (AGN). We determine the prevalence of X-ray AGNs in the star-forming region of the BPT diagram and discuss the reasons behind this apparent misclassification, focusing primarily on relatively massive ({log}({M}* )≳…