Search Publications
Turbulence-driven Solar Wind Heating and Energization of Pickup Protons in the Outer Heliosphere
Isenberg, Philip A.
We improve and extend the ``dominant turbulence'' model of Isenberg et al., which describes the turbulent heating of the distant solar wind by the dissipation of wave energy generated by the isotropization of interstellar pickup protons. We first modify some of the detailed expressions in Isenberg et al. to fully incorporate the effects of wave di…
Local Correlation Tracking and the Magnetic Induction Equation
Schuck, P. W.
Recently, local correlation tracking has been applied to magnetograms to estimate photospheric velocities. This Letter demonstrates that local correlation tracking is inconsistent with the magnetic induction equation, which governs the temporal evolution of the photospheric magnetograms. A modified formulation, consistent with the magnetic inducti…
The Evolution of Coronal Mass Ejection Density Structures
Gombosi, T. I.; Lugaz, N.; Manchester, W. B., IV
We present a discussion of the time evolution of the mass and energy of a model coronal mass ejection (CME), analyzing both synthetic coronograph images and three-dimensional data of the numerical ideal magnetohydrodynamics (MHD) simulation. Our global steady state coronal model possesses high-latitude coronal holes and a helmet streamer structure…
Decomposition of the Visible and Dark Matter in the Einstein Ring 0047-2808 by Semilinear Inversion
Dye, S.; Warren, S. J.
We measure the mass density profile of the lens galaxy in the Einstein ring system 0047-2808 using our semilinear inversion method developed in an earlier paper. By introducing an adaptively gridded source plane, we are able to eliminate the need for regularization of the inversion. This removes the problem of a poorly defined number of degrees of…
The X-Ray Emissions from the M87 Jet: Diagnostics and Physical Interpretation
Perlman, Eric S.; Wilson, Andrew S.
We reanalyze the deep Chandra observations of the M87 jet, first examined by Wilson & Yang in 2002. By employing an analysis chain that also includes image deconvolution, knots HST-1 and I are fully separated from adjacent emission. We derive the spatially resolved X-ray spectrum of the jet using the most recent response functions and find sli…
An HST Search for Supernovae Accompanying X-Ray Flashes
Cenko, S. B.; Peterson, B. A.; Price, P. A. +24 more
We present the results from a Hubble Space Telescope ACS search for supernovae associated with X-ray flashes 020903, 040701, 040812, and 040916. We find strong evidence that XRF 020903 (z=0.25) was associated with a SN 1998bw-like supernova and confirm this using optical spectroscopy at t~25 days. We find no evidence, however, for SN 1998bw-like s…
Kelu-1 Is a Binary L Dwarf: First Brown Dwarf Science from Laser Guide Star Adaptive Optics
Leggett, S. K.; Liu, Michael C.
We present near-infrared (1-2.4 µm) imaging of the L dwarf Kelu-1 obtained with the Keck sodium laser guide star adaptive optics (LGS AO) system as part of a high angular resolution survey for substellar binaries. Kelu-1 was one of the first free-floating L dwarfs identified, and the origin of its overluminosity compared to objects of simila…
Magnetic Reconnection Rate and Flux-Rope Acceleration of Two-Ribbon Flares
Lin, Jun; Xu, Yan; Qiu, Jiong +3 more
Forbes & Lin derived simple equations to link the properties of magnetic reconnection in the corona to observed signatures of solar flares. We measured the photospheric magnetic fields and the flare ribbon separation speeds then applied these equations to derive two physical terms for the magnetic reconnection rates: the rate of magnetic flux …
Detection of Ne VIII in the Low-Redshift Warm-Hot Intergalactic Medium
Tripp, Todd M.; Sembach, Kenneth R.; Savage, Blair D. +2 more
High-resolution FUSE and STIS observations of the bright QSO HE 0226-4110 (zem=0.495) reveal the presence of a multiphase absorption-line system at zabs(OVI)=0.20701 containing absorption from H I (Lyα to Lyθ), C III, O III, O IV, O VI, N III, Ne VIII, Si III, S VI, and possibly S V. Single-component fits to the Ne VIII and O…
Weak-Lensing Analysis of the z~=0.8 Cluster CL 0152-1357 with the Advanced Camera for Surveys
Ford, H. C.; Demarco, R.; Rosati, P. +5 more
We present a weak-lensing analysis of the X-ray-luminous cluster CL 0152-1357 at z~=0.84 using Hubble Space Telescope/Advanced Camera for Surveys (ACS) observations. The unparalleled resolution and sensitivity of ACS enable us to measure weakly distorted, faint background galaxies to the extent that the number density reaches ~175 arcmin-2