Search Publications
Nonlinear and Linear Timescales near Kinetic Scales in Solar Wind Turbulence
Matthaeus, W. H.; Chapman, S. C.; Karimabadi, H. +8 more
The application of linear kinetic treatments to plasma waves, damping, and instability requires favorable inequalities between the associated linear timescales and timescales for nonlinear (e.g., turbulence) evolution. In the solar wind these two types of timescales may be directly compared using standard Kolmogorov-style analysis and observationa…
Probing the Crust of the Neutron Star in EXO 0748-676
Degenaar, N.; Wijnands, R.; Wolff, M. T. +7 more
X-ray observations of quiescent X-ray binaries have the potential to provide insight into the structure and the composition of neutron stars. EXO 0748-676 had been actively accreting for over 24 yr before its outburst ceased in late 2008. Subsequent X-ray monitoring revealed a gradual decay of the quiescent thermal emission that can be attributed …
Three Gravitationally Lensed Supernovae behind CLASH Galaxy Clusters
Donahue, Megan; Broadhurst, Tom; Filippenko, Alexei V. +42 more
We report observations of three gravitationally lensed supernovae (SNe) in the Cluster Lensing And Supernova survey with Hubble (CLASH) Multi-Cycle Treasury program. These objects, SN CLO12Car (z = 1.28), SN CLN12Did (z = 0.85), and SN CLA11Tib (z = 1.14), are located behind three different clusters, MACSJ1720.2+3536 (z = 0.391), RXJ1532.9+3021 (z…
Atmospheric Characterization of Five Hot Jupiters with the Wide Field Camera 3 on the Hubble Space Telescope
Deming, Drake; Madhusudhan, Nikku; Ranjan, Sukrit +4 more
We probe the structure and composition of the atmospheres of five hot Jupiter exoplanets using the Hubble Space Telescope Wide Field Camera 3 (WFC3) instrument. We use the G141 grism (1.1-1.7 µm) to study TrES-2b, TrES-4b, and CoRoT-1b in transit; TrES-3b in secondary eclipse; and WASP-4b in both. This wavelength region includes a predicted …
Supernova 2010as: The Lowest-velocity Member of a Family of Flat-velocity Type IIb Supernovae
Morrell, Nidia; Nomoto, Ken'ichi; Phillips, Mark M. +23 more
We present extensive optical and near-infrared photometric and spectroscopic observations of the stripped-envelope supernova SN 2010as. Spectroscopic peculiarities such as initially weak helium features and low expansion velocities with a nearly flat evolution place this object in the small family of events previously identified as transitional Ty…
Fast and Furious: Shock Heated Gas as the Origin of Spatially Resolved Hard X-Ray Emission in the Central 5 kpc of the Galaxy Merger NGC 6240
Elvis, Martin; Zezas, Andreas; Risaliti, Guido +7 more
We have obtained a deep, subarcsecond resolution X-ray image of the nuclear region of the luminous galaxy merger NGC 6240 with Chandra, which resolves the X-ray emission from the pair of active nuclei and the diffuse hot gas in great detail. We detect extended hard X-ray emission from kT ~ 6 keV (~70 MK) hot gas over a spatial scale of 5 kpc, indi…
C/O Abundance Ratios, Iron Depletions, and Infrared Dust Features in Galactic Planetary Nebulae
Delgado-Inglada, Gloria; Rodríguez, Mónica
We study the dust present in 56 Galactic planetary nebulae (PNe) through their iron depletion factors, their C/O abundance ratios (in 51 objects), and the dust features that appear in their infrared spectra (for 33 objects). Our sample objects have deep optical spectra of good quality, and most of them also have ultraviolet observations. We use th…
The Intrinsic Two-dimensional Size of Sagittarius A*
Ghez, A. M.; Morris, M. R.; Bower, Geoffrey C. +9 more
We report the detection of the two-dimensional structure of the radio source associated with the Galactic Center black hole, Sagittarius A*, obtained from Very Long Baseline Array observations at a wavelength of 7 mm. The intrinsic source is modeled as an elliptical Gaussian with major-axis size 35.4 × 12.6 RS in position angle 95° east…
A Strongly Heated Neutron Star in the Transient Z Source MAXI J0556-332
Remillard, Ronald A.; Homan, Jeroen; Cackett, Edward M. +5 more
We present Chandra, XMM-Newton, and Swift observations of the quiescent neutron star in the transient low-mass X-ray binary MAXI J0556-332. Observations of the source made during outburst (with the Rossi X-ray Timing Explorer) reveal tracks in its X-ray color-color and hardness-intensity diagrams that closely resemble those of the neutron-star Z s…
Combined Multipoint Remote and in situ Observations of the Asymmetric Evolution of a Fast Solar Coronal Mass Ejection
Frahm, R. A.; Zhang, T. L.; Möstl, C. +8 more
We present an analysis of the fast coronal mass ejection (CME) of 2012 March 7, which was imaged by both STEREO spacecraft and observed in situ by MESSENGER, Venus Express, Wind, and Mars Express. Based on detected arrivals at four different positions in interplanetary space, it was possible to strongly constrain the kinematics and the shape of th…