Search Publications
A Symmetric Inner Cavity in the HD 141569A Circumstellar Disk
Augereau, J. -C.; Boccaletti, A.; Lagrange, A. -M. +6 more
Some circumstellar disks, called transitional or hybrid disks, present characteristics of both protoplanetary disks (significant amount of gas) and debris disks (evolved structures around young main-sequence stars, composed of second generation dust, from collisions between planetesimals). Therefore, they are ideal astrophysical laboratories to wi…
Herschel/HIFI Spectral Mapping of C+, CH+, and CH in Orion BN/KL: The Prevailing Role of Ultraviolet Irradiation in CH+ Formation
Bergin, Edwin A.; Neufeld, David A.; Ossenkopf-Okada, Volker +8 more
The CH+ ion is a key species in the initial steps of interstellar carbon chemistry. Its formation in diverse environments where it is observed is not well understood, however, because the main production pathway is so endothermic (4280 K) that it is unlikely to proceed at the typical temperatures of molecular clouds. We investigate the …
IDCS J1426.5+3508: Weak Lensing Analysis of a Massive Galaxy Cluster at z = 1.75
Massey, Richard; Rhodes, Jason; Marrone, Daniel P. +7 more
We present a weak lensing study of the galaxy cluster IDCS J1426.5+3508 at z = 1.75, which is the highest-redshift strong lensing cluster known and the most distant cluster for which a weak lensing analysis has been undertaken. Using F160W, F814W, and F606W observations with the Hubble Space Telescope, we detect tangential shear at 2σ significance…
The Magnetic Field of L1544. I. Near-infrared Polarimetry and the Non-uniform Envelope
Tassis, K.; Goldsmith, Paul F.; Clemens, Dan P.
The magnetic field (B-field) of the starless dark cloud L1544 has been studied using near-infrared (NIR) background starlight polarimetry (BSP) and archival data in order to characterize the properties of the plane-of-sky B-field. NIR linear polarization measurements of over 1700 stars were obtained in the H band and 201 of these were also measure…
Chandra and XMM-Newton X-Ray Observations of the Hyperactive T Tauri Star RY Tau
Skinner, Stephen L.; Güdel, Manuel; Audard, Marc
We present results of pointed X-ray observations of the accreting jet-driving T Tauri star RY Tau using Chandra and XMM-Newton. We obtained high-resolution grating spectra and excellent-quality CCD spectra and light curves with the objective of identifying the physical mechanisms underlying RY Tau’s bright X-ray emission. Grating spectra reveal nu…
Three-dimensional Geometry of a Current Sheet in the High Solar Corona: Evidence for Reconnection in the Late Stage of the Coronal Mass Ejections
Vourlidas, Angelos; Kwon, Ryun-Young; Webb, David
Motivated by the standard flare model, ray-like structures in the wake of coronal mass ejections (CMEs) have been often interpreted as proxies of the reconnecting current sheet connecting the CME with the postflare arcade. We present the three-dimensional properties of a post-CME ray derived from white light images taken from three different viewi…
The Unusual Galactic Center Radio Source N3
Morris, M. R.; Mills, E. A. C.; Mutel, R. +4 more
Here, we report on new multi-wavelength radio observations of the unusual point source “N3” that appears to be located in the vicinity of the Galactic Center (GC). VLA observations between 2 and 50 GHz reveal that N3 is a compact and bright source (56 mJy at 10 GHz) with a non-thermal spectrum superimposed upon the non-thermal radio filaments (NTF…
Testing the Effects of Expansion on Solar Wind Turbulence
Chen, Christopher H. K.; Vech, Daniel
We present a multi-spacecraft approach to test the predictions of recent studies on the effect of solar wind expansion on the radial spectral, variance, and local 3D anisotropies of the turbulence. We found that on small scales (5000-10,000 km) the power levels of the B-trace structure functions do not depend on the sampling direction with respect…
Multi-spacecraft Analysis of Energetic Heavy Ion and Interplanetary Shock Properties in Energetic Storm Particle Events near 1 au
Jian, L. K.; Mason, G. M.; Desai, M. I. +3 more
We examine the longitude distribution of and relationship between interplanetary (IP) shock properties and ∼0.1-20 MeV nucleon-1 O and Fe ions during seven multi-spacecraft energetic storm particle (ESP) events at 1 au. These ESP events were observed at two spacecraft and were primarily associated with low Mach number, quasi-perpendicul…
Analysis of the Herschel/Hexos Spectral Survey Toward Orion South: A Massive Protostellar Envelope with Strong External Irradiation
Menten, K. M.; Pagani, L.; Lis, D. C. +14 more
We present results from a comprehensive submillimeter spectral survey toward the source Orion South, based on data obtained with the Heterodyne Instrument for the Far-Infrared instrument on board the Herschel Space Observatory, covering the frequency range of 480 to 1900 GHz. We detect 685 spectral lines with signal-to-noise ratios (S/Ns) > 3σ,…