Search Publications
Structure of the Near-Surface Layers of the Sun: Asphericity and Time Variation
Basu, Sarbani; Antia, H. M.; Bogart, Richard S.
We present results on the structure of the near-surface layers of the Sun obtained by inverting frequencies of high-degree solar modes from ``ring diagrams.'' We have results for eight epochs between 1996 June and 2003 October. The frequencies for each epoch were obtained from ring diagrams constructed from Michelson Doppler Imager (MDI) Dopplergr…
MS 2053.7-0449: Confirmation of a Bimodal Mass Distribution from Strong Gravitational Lensing
Limousin, Marceau; de Diego, J. A.; Verdugo, T.
We present the first strong-lensing study of the mass distribution in the cluster MS 2053-04 based on HST archive data. This massive, X-ray luminous cluster has a redshift z=0.583 and is composed of two structures that are gravitationally bound to each other. The cluster has one multiply imaged system composed of a double gravitational arc. We hav…
Isophotal Structure and Dust Distribution in Radio-loud Elliptical Galaxies
Macchetto, F. D.; Capetti, A.; Sparks, W. B. +4 more
We investigate isophotal properties and dust morphology in the nuclear regions of 84 radio galaxies, imaged in the optical and near-infrared as part of Hubble Space Telescope snapshot surveys. We present a sample-wide trend between host galaxy isophotal structure and the inclination of dusty circumnuclear disks at the centers of 13 of these object…
Radio and White-Light Coronal Signatures Associated with the RHESSI Hard X-Ray Event of 2002 July 23
Krucker, S.; Kaiser, M. L.; Gary, D. E. +3 more
Simultaneous radio, white-light, and hard X-ray (HXR) observations for the 2002 July 23 γ-ray flare event are used to establish the relationship of a complex type III-like burst to the corresponding coronal mass ejection (CME) and the coronal electron acceleration signatures observed in the decimeter/microwave (dm-cm) emissions and X-rays. We find…
Stellar Populations of Luminous Evolved Galaxies at z ~ 1.5
McGrath, Elizabeth J.; Stockton, Alan; Canalizo, Gabriela
Observational evidence has been mounting over the past decade that at least some luminous (~2L*) galaxies have formed nearly all of their stars within a short period of time, only (1-2)×109 yr after the big bang. These are examples of the first major episodes of star formation in the universe and provide insights into the formation of t…
SMA High Angular Resolution Imaging of the Lensed Quasar APM 08279+5255
Iono, D.; Wilner, D. J.; Krips, M. +4 more
We present Submillimeter Array observations of the z=3.91 gravitationally lensed broad absorption line quasar APM 08279+5255 which spatially resolve the 1.0 mm (200 µm rest frame) dust continuum emission. At 0.4" resolution, the emission is separated into two components, a stronger, extended one to the northeast (46+/-5 mJy) and a weaker, co…
Dust Rings and Filaments around the Isolated Young Star V1331 Cygni
Quanz, S. P.; Apai, D.; Henning, Th.
We characterize the small- and large-scale environment of the young star V1331 Cygni with high-resolution HST WFPC2 and Digitized Sky Survey images. In addition to a previously known outer dust ring (~30'' in diameter), the WFPC2 scattered light image reveals an inner dust ring for the first time. This ring has a maximum radius of ~6.5<…
Reconstructing Spherical Nonlinear Force-free Field in the Solar Corona
Wu, S. T.; Zhang, H. Q.; Fang, C. +3 more
We present a spherical nonlinear force-free field (NFFF) reconstructing method based on the photospheric vector magnetograms. The importance of this method is its ability to reveal the NFFF configurations, which is necessary for understanding the physical mechanisms of the initiation of the large-scale solar eruptions, such as coronal mass ejectio…
Velocity Profiles in the Solar Corona from Multi-Instrument Observations
Lamy, P.; Lallement, R.; Quémerais, E. +1 more
We present a method to derive outflow velocities in the solar corona using different data sets, including solar wind mass flux coming from the SWAN SOHO instrument, electron density values from LASCO-C2, and interplanetary solar wind velocities derived from ground-based interplanetary scintillation observations (IPS). In a first step, we combine t…
Evolution of Magnetic Nonpotentiality in NOAA AR 10486
Liu, Y.; Zhang, H.; Kurokawa, H. +2 more
The active region NOAA 10486 was one of the most flare-productive regions during solar cycle 23. In this paper, we focus our analysis on the daily evolution of magnetic nonpotentiality for this region from 2003 October 26 to October 30. Daily averaged values of three nonpotential parameters: magnetic shear angle, line-of-sight current, and current…