Search Publications
A Wide-Field Hubble Space Telescope Study of the Cluster Cl 0024+1654 at z=0.4. II. The Cluster Mass Distribution
Smith, Graham P.; Treu, Tommaso; Smail, Ian +6 more
We present a comprehensive lensing analysis of the rich cluster Cl 0024+1654 (z=0.395) based on panoramic sparse-sampled imaging conducted with the WFPC2 and STIS cameras on board the Hubble Space Telescope. By comparing higher fidelity signals in the limited STIS data with the wider field data available from WFPC2, we demonstrate an ability to de…
A Uniform Database of 2.4-45.4 Micron Spectra from the Infrared Space Observatory Short Wavelength Spectrometer
Sloan, G. C.; Kraemer, Kathleen E.; Price, Stephan D. +1 more
We present a complete set of all valid SWS full-scan 2.4-45.4 µm spectra processed and renormalized in as uniform a manner as possible. The processing produces a single spectrum for each observation from the 288 individual spectral segments, which are the most processed form available from the ISO archive. The spectra, and the programs used …
Dynamical and Physical Properties of a Post-Coronal Mass Ejection Current Sheet
Lin, Jun; Raymond, John C.; Li, Jing +3 more
In the eruptive process of the Kopp-Pneuman type, the closed magnetic field is stretched by the eruption so much that it is usually believed to be ``open'' to infinity. Formation of the current sheet in such a configuration makes it possible for the energy in the coronal magnetic field to quickly convert into thermal and kinetic energies and cause…
Distances to nearby galaxies in Sculptor
Sarajedini, A.; Dolphin, A. E.; Grebel, E. K. +7 more
We present an analysis of Hubble Space Telescope/WFPC2 images of nine nearby galaxies in Sculptor. We derive their distances from the luminosity of the tip of the red giant branch stars with a typical accuracy of ~ 12%. Their distances are 4.21 Mpc (Sc 22), 4.92 Mpc (DDO 226), 3.94 Mpc (NGC 253), 3.40 Mpc (KDG 2), 3.34 Mpc (DDO 6), 3.42 Mpc (ESO 5…
Steps toward interstellar silicate mineralogy. VII. Spectral properties and crystallization behaviour of magnesium silicates produced by the sol-gel method
Mutschke, H.; Henning, Th.; Posch, Th. +2 more
Amorphous silicate particles are generally assumed to be the main dust component in the envelopes of oxygen-rich evolved stars and may be considered the precursors of the pure crystalline enstatite and forsterite particles detected by ISO. We present optical constants in the broad wavelength range 0.2-500 mu m for a unique series of pure amorphous…
Active longitudes in sunspot activity: Century scale persistence
Usoskin, I. G.; Berdyugina, S. V.
A novel analysis of sunspot group data for the past 120 years reveals that sunspots in both northern and southern hemispheres are formed preferably in two persistent active longitudes separated by 180°. In the Carrington reference frame, the active longitudes continuously migrate in phase with respect to the Carrington meridian with a variable rat…
An energetic stellar outburst accompanied by circumstellar light echoes
Munari, U.; Sparks, William B.; Bond, Howard E. +6 more
Some classes of stars, including novae and supernovae, undergo explosive outbursts that eject stellar material into space. In 2002, the previously unknown variable star V838 Monocerotis brightened suddenly by a factor of ~104. Unlike a supernova or nova, it did not explosively eject its outer layers; rather, it simply expanded to become…
A Young White Dwarf Companion to Pulsar B1620-26: Evidence for Early Planet Formation
Richer, Harvey B.; Hansen, Brad M.; Stairs, Ingrid H. +2 more
The pulsar B1620-26 has two companions, one of stellar mass and one of planetary mass. We detected the stellar companion with the use of Hubble Space Telescope observations. The color and magnitude of the stellar companion indicate that it is an undermassive white dwarf (0.34 +/- 0.04 solar mass) of age 480 × 106 +/- 140 × 106
Direct Detection of a Coronal Mass Ejection-Associated Shock in Large Angle and Spectrometric Coronagraph Experiment White-Light Images
Wu, S. T.; Howard, R. A.; Vourlidas, A. +2 more
The Large Angle and Spectrometric Coronagraph Experiment (LASCO) C2 and C3 coronagraphs recorded a unique coronal mass ejection (CME) on 1999 April 2. The event did not have the typical three-part CME structure and involved a small-filament eruption without any visible overlying streamer ejecta. The event exhibited an unusually clear signature of …
The Structure and Dynamics of Luminous and Dark Matter in the Early-Type Lens Galaxy of 0047-281 at z = 0.485
Treu, Tommaso; Koopmans, Léon V. E.
We have measured the kinematic profile of the early-type (E/S0) lens galaxy in the system 0047-281 (z=0.485) with the Echelle Spectrograph and Imager (ESI) on the W. M. Keck II Telescope, as part of the Lenses Structure and Dynamics (LSD) Survey. The central velocity dispersion is σ=229+/-15 km s-1, and the dispersion profile is nearly …