Search Publications
The metal-rich atmosphere of the exo-Neptune HAT-P-26b
Madhusudhan, Nikku; MacDonald, Ryan J.
Transmission spectroscopy is enabling precise measurements of atmospheric H2O abundances for numerous giant exoplanets. For hot Jupiters, relating H2O abundances to metallicities provides a powerful probe of their formation conditions. However, metallicity measurements for Neptune-mass exoplanets are only now becoming viable.…
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 …
Warm FIRE: simulating galaxy formation with resonant sterile neutrino dark matter
Faucher-Giguère, Claude-André; Hopkins, Philip F.; Wetzel, Andrew +8 more
We study the impact of a warm dark matter (WDM) cosmology on dwarf galaxy formation through a suite of cosmological hydrodynamical zoom-in simulations of M_halo ≈ 10^{10} M_{⊙} dark matter haloes as part of the Feedback in Realistic Environments (FIRE) project. A main focus of this paper is to evaluate the combined effects of dark matter physics a…
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…
Masses and ages for metal-poor stars. A pilot programme combining asteroseismology and high-resolution spectroscopic follow-up of RAVE halo stars
Valentini, M.; García, R. A.; Chiappini, C. +10 more
Context. Very metal-poor halo stars are the best candidates for being among the oldest objects in our Galaxy. Samples of halo stars with age determination and detailed chemical composition measurements provide key information for constraining the nature of the first stellar generations and the nucleosynthesis in the metal-poor regime.
Aims: A…
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…
Host galaxies of high-redshift extremely red and obscured quasars
Brandt, W. N.; Ross, Nicholas P.; Strauss, Michael A. +9 more
We present Hubble Space Telescope 1.4-1.6 µm images of the hosts of 10 extremely red quasars (ERQs) and six type 2 quasar candidates at z = 2-3. ERQs, whose bolometric luminosities range between 1047 and 1048 erg s-1, show spectroscopic signs of powerful ionized winds, whereas type 2 quasar candidates are les…
Spectral variations of Lyman α emission within strongly lensed sources observed with MUSE
Richard, J.; Verhamme, A.; Clément, B. +13 more
We present an analysis of H I Lyman α emission in deep VLT/MUSE observations of two highly magnified and extended galaxies at z=3.5 and 4.03, including a newly discovered, almost complete Einstein ring. While these Lyman α haloes are intrinsically similar to the ones typically seen in other MUSE deep fields, the benefits of gravitational lensing a…
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…