Search Publications
Compositional Diversity in the Atmospheres of Hot Neptunes, with Application to GJ 436b
Fortney, J. J.; Moses, J. I.; Madhusudhan, N. +6 more
Neptune-sized extrasolar planets that orbit relatively close to their host stars—often called "hot Neptunes"—are common within the known population of exoplanets and planetary candidates. Similar to our own Uranus and Neptune, inefficient accretion of nebular gas is expected produce hot Neptunes whose masses are dominated by elements heavier than …
Spiral Arms in the Asymmetrically Illuminated Disk of MWC 758 and Constraints on Giant Planets
Kuzuhara, M.; Tamura, M.; Ishii, M. +71 more
We present the first near-IR scattered light detection of the transitional disk associated with the Herbig Ae star MWC 758 using data obtained as part of the Strategic Exploration of Exoplanets and Disks with Subaru, and 1.1 µm Hubble Space Telescope/NICMOS data. While submillimeter studies suggested there is a dust-depleted cavity with r = …
Escape of Lyman continuum radiation from local galaxies. Detection of leakage from the young starburst Tol 1247-232
Hayes, M.; Zackrisson, E.; Leitet, E. +2 more
Context. It has been suggested that the escape fraction of hydrogen ionizing photons (fesc) from galaxies is evolving with time, but the picture is far from clear. While evidence for significant escape fractions has been found at high redshifts in several studies, the picture looks different in the closer universe. The lack of local det…
The VLT-FLAMES Tarantula Survey. XI. A census of the hot luminous stars and their feedback in 30 Doradus
van Loon, J. Th.; Crowther, P. A.; Herrero, A. +16 more
Context. The VLT-FLAMES Tarantula Survey has an extensive view of the copious number of massive stars in the 30 Doradus (30 Dor) star forming region of the Large Magellanic Cloud. These stars play a crucial role in our understanding of the stellar feedback in more distant, unresolved star forming regions.
Aims: The first comprehensive census …
Spectral Fingerprints of Earth-like Planets Around FGK Stars
Sasselov, Dimitar; Kaltenegger, Lisa; Rugheimer, Sarah +2 more
We present model atmospheres for an Earth-like planet orbiting the entire grid of main sequence FGK stars with effective temperatures ranging from Teff = 4250K to Teff = 7000K in 250K intervals. We model the remotely detectable spectra of Earth-like planets for clear and cloudy atmospheres at the 1AU equivalent distance from the VIS to IR (0.4 {\m…
Macroclumping as solution of the discrepancy between Hα and P v mass loss diagnostics for O-type stars
Hamann, W. -R.; Oskinova, L. M.; Aret, A. +3 more
Context. Recent studies of O-type stars have demonstrated that discrepant mass-loss rates are obtained when different diagnostic methods are employed. Fitting the unsaturated UV resonance lines (e.g., P v) gives drastically lower values than obtained from the Hα emission. Wind inhomogeneity (so-called "clumping") may be the main cause of this disc…
Calibrating C-IV-based Black Hole Mass Estimators
Park, Daeseong; Denney, Kelly D.; Woo, Jong-Hak +1 more
We present the single-epoch black hole mass estimators based on the C IV λ1549 broad emission line, using the updated sample of the reverberation-mapped active galactic nuclei and high-quality UV spectra. By performing multi-component spectral fitting analysis, we measure the C IV line widths (FWHMC IV and line dispersion, σC IV <…
Far-ultraviolet Detection of the Suspected Subdwarf Companion to the Be Star 59 Cygni
Gies, Douglas R.; Peters, Geraldine J.; Pewett, Tiffany D. +2 more
We report on the detection of a hot subdwarf component in the Be binary system, 59 Cygni. The spectral signature is found in cross-correlation functions of photospheric model spectra with far-ultraviolet spectra obtained by the International Ultraviolet Explorer Satellite, and we used radial velocities from the cross-correlation functions to deter…
The spectroscopic evolution of the γ-ray emitting classical nova Nova Mon 2012. I. Implications for the ONe subclass of classical novae
Cheung, C. C.; Shore, S. N.; Starrfield, S. +4 more
Aims: Among the classical novae, the ONe subgroup, distinguished by their large overabundance of neon, are thought to occur on the most massive white dwarfs. Nova Mon 2012 was the first classical nova to be detected as a high energy γ-ray transient, by Fermi-LAT, before its optical discovery. The first optical spectra obtained about 55 days a…
Weak Hard X-Ray Emission from Two Broad Absorption Line Quasars Observed with NuSTAR: Compton-thick Absorption or Intrinsic X-Ray Weakness?
Harrison, F. A.; Stern, D.; Zhang, W. W. +22 more
We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are amo…