Search Publications
Evidence for Deuterium Astration in the Planetary Nebula Sh 2-216?
Rauch, Thomas; Chayer, Pierre; Kruk, Jeffrey W. +2 more
We present FUSE observations of the line of sight to WD 0439+466 (LS V +46 21), the central star of the old planetary nebula Sh 2-216. The FUSE data show absorption by many interstellar and stellar lines, in particular D I, H2 (J=0-9), HD J=0-1, and CO. Many other stellar and ISM lines are detected in the STIS E140M HST spectra of this …
Dynamical Parameters for AM 0644-741
Antunes, Alex; Wallin, John
We present a simulation match to the 2004 Hubble Heritage high-resolution optical images of AM 0644-741. In N-body/smoothed particle hydrodynamics (SPH) simulations of AM 0644-741, we recreate the star formation features, as well as the underlying kinematics. Our simulations contain sufficient numerical density to accurately distinguish the overla…
Extraction of Halo Coronal Mass Ejection Asymmetry Information from LASCO Coronagraph Images
Webb, D. F.; Ling, A. G.
A method for quantifying the asymmetry attributes of coronal mass ejections (CMEs) is described. The technique developed is applied to a set of full-halo CMEs observed from 1997 to the end of 2000 by the Large Angle Spectrometric Coronagraph (LASCO) instrument on board the Solar and Heliospheric Observatory (SOHO) spacecraft. A cross section of ev…
Diffusive Compression Acceleration of Energetic Particles with an Application to Shock Acceleration near Injection Energies
Zhang, Ming
The behavior of energetic charged particles accelerated by a continuous plasma compression profile is explored in the framework of diffusion. At high enough energies, the accelerated particles have a power-law spectrum with a slope generally steeper than a shock spectrum with the same compression ratio. The spectral slope depends on the ratio of t…
Erratum: ``A Potential Supernova Remnant-X-Ray Binary Association in M31'' (ApJ, 634, 365 [2005])
Williams, Benjamin F.; Kong, Albert K. H.; Kolb, U. +3 more
We have discovered a flaw in the light curves we previously generated using the XMM-Newton Science Analysis Software (SAS), which can produce spurious Type A power density spectra (R. Barnard et al. 2007, preprints astro-ph/0610035, astro-ph/0703120). This is the type of variability associated with disk-accreting binary systems (R. Barnard et al. …
Ultra-Low-Frequency Solar He II 30.4 nm Pulsations
Didkovsky, L.; Judge, D. L.; Gangopadhyay, P. +2 more
Solar EUV and X-ray measurements from the Charge, Element and Isotope Analysis System/Solar EUV Monitor (CELIAS/SEM) on board Solar and Heliospheric Observatory (SOHO) and the Geostationary Operational Environmental Satellites (GOES) have been studied for four time periods. Two ultra-low-frequency CELIAS/SEM He II 30.4 nm pulsations were observed …
The Emerging Features of Bipolar Magnetic Regions during Solar Minima
Feng, Xueshang; Song, Wenbin
Solar magnetic synoptic charts obtained by NSO/Kitt Peak and SOHO/MDI are analyzed in order to study the appearance of bipolar magnetic regions (BMRs) during solar minima. We find that the emergence of long-lived BMRs have three typical features. (1) The emergence rate of BMRs in the new cycle increases about 3 times faster than the rate of the ol…
A Direct Empirical Proof of the Existence of Dark Matter
Bradač, Maruša; Jones, Christine; Gonzalez, Anthony H. +4 more
We present new weak-lensing observations of 1E 0657-558 (z=0.296), a unique cluster merger, that enable a direct detection of dark matter, independent of assumptions regarding the nature of the gravitational force law. Due to the collision of two clusters, the dissipationless stellar component and the fluid-like X-ray-emitting plasma are spatially…
Determining Central Black Hole Masses in Distant Active Galaxies and Quasars. II. Improved Optical and UV Scaling Relationships
Peterson, Bradley M.; Vestergaard, Marianne
We present four improved empirical relationships useful for estimating the central black hole mass in nearby AGNs and distant luminous quasars alike using either optical or UV single-epoch spectroscopy. These mass scaling relationships between line widths and luminosity are based on recently improved empirical relationships between the broad-line …
The Sloan Lens ACS Survey. III. The Structure and Formation of Early-Type Galaxies and Their Evolution since z ~ 1
Treu, Tommaso; Koopmans, Léon V. E.; Bolton, Adam S. +2 more
We present a joint gravitational lensing and stellar-dynamical analysis of 15 massive field early-type galaxies selected from the Sloan Lens ACS (SLACS) Survey. The following numerical results are found: (1) A joint likelihood gives an average logarithmic density slope for the total mass density of <γ'>=2.01+0.02-0…