Search Publications
The host galaxies of luminous quasars
Baum, Stefi A.; O'Dea, Christopher P.; Dunlop, James S. +5 more
We present the results of a deep Hubble Space Telescope (HST)/Wide Field and Planetary Camera 2 imaging study of 17 quasars at z~= 0.4, designed to determine the properties of their host galaxies. The sample consists of quasars with absolute magnitudes in the range -24 >=MV>=- 28, allowing us to investigate host galaxy properties …
Disk and Halo Wide Binaries from the Revised Luyten Catalog: Probes of Star Formation and MACHO Dark Matter
Gould, Andrew; Chanamé, Julio
We present a catalog of 1147 candidate common proper motion binaries selected from the revised New Luyten Two-Tenths Catalog (NLTT). Among these, we identify 999 genuine physical pairs using the measured proper-motion difference and the relative positions of each binary's components on a reduced proper motion (RPM) diagram. The RPM positions also …
A multiwavelength study of solar flare waves. II. Perturbation characteristics and physical interpretation
Magdalenić, J.; Vršnak, B.; Hanslmeier, A. +2 more
The study of solar flare waves - globally propagating wave-like disturbances usually observed in Hα as Moreton waves - has recently come back into focus prompted by the observation of coronal waves in the EUV with the SOHO/EIT instrument (``EIT waves"), and in several additional wavelength channels. We study 12 flare wave events in order to determ…
An Unveiling Event in the Type 2 Active Galactic Nucleus NGC 4388:A Challenge for a Parsec-Scale Absorber
Fiore, F.; Elvis, Martin; Miller, J. M. +3 more
We present two Rossi X-Ray Timing Explorer (RXTE) Proportional Counter Array (PCA) observations of the type 2 Seyfert galaxy NGC 4388 caught in an unusual low X-ray absorption state. The observations were triggered by a detection in the 1.5-3 keV band of the RXTE all-sky monitor. NGC 4388 was found at a somewhat high continuum level [f(2-10 keV)=8…
Discovery of Face-on Counterparts of Chain Galaxies in the Tadpole Advanced Camera for Surveys Field
Elmegreen, Bruce G.; Elmegreen, Debra Meloy; Hirst, Amelia C.
The background field of the Tadpole galaxy image taken with the Hubble Space Telescope Advanced Camera for Surveys contains 87 clump clusters that are probably low-inclination versions of the 69 chain galaxies that we found in a previous paper. This conclusion follows from the similarity in colors and apparent magnitudes of the brightest clumps in…
Radar: The Cassini Titan Radar Mapper
Lorenz, R. D.; Soderblom, L. A.; Ostro, S. J. +19 more
The Cassini RADAR instrument is a multimode 13.8 GHz multiple-beam sensor that can operate as a synthetic-aperture radar (SAR) imager, altimeter, scatterometer, and radiometer. The principal objective of the RADAR is to map the surface of Titan. This will be done in the imaging, scatterometer, and radiometer modes. The RADAR altimeter data will pr…
Role of projection effects on solar coronal mass ejection properties: 1. A study of CMEs associated with limb activity
St. Cyr, O. C.; Stanger, A. L.; Burkepile, J. T. +2 more
Many properties of Coronal Mass Ejections (CMEs), such as size, location and brightness, have been determined from measurements of white light coronal observations. We expect the average properties derived from these measurements contain systematic inaccuracies due to projection effects and suggest that CME properties are most accurately determine…
Subgalactic Clumps at High Redshift: A Fragmentation Origin?
Gerhard, Ortwin; Westera, Pieter; Immeli, Andreas +1 more
We investigate the origin of the clumpy structures observed at high redshift, such as chain galaxies. We use a three-dimensional chemodynamical simulation describing the dynamics of stars and a two-phase interstellar medium, as well as feedback processes from the stars. For high efficiency of energy dissipation in the cold cloud medium, the initia…
Solar magnetic elements at 0.1 arcsec resolution. General appearance and magnetic structure
Hansteen, V. H.; Carlsson, M.; Berger, T. E. +6 more
New observations of solar magnetic elements in a remnant active region plage near disk center are presented. The observations were obtained at the recently commissioned Swedish 1-m Solar Telescope on La Palma. We examine a single 430.5 nm G-band filtergram that resolves ∼70 km (0.1 arcsec) structures and find new forms of magnetic structures in th…
Discovery of Hard Nonthermal Pulsed X-Ray Emission from the Anomalous X-Ray Pulsar 1E 1841-045
Kuiper, L.; Hermsen, W.; Mendez, M.
We report the discovery of nonthermal pulsed X-ray/soft gamma-ray emission up to ~150 keV from the anomalous 11.8 s X-ray pulsar AXP 1E 1841-045 located near the center of supernova remnant Kes 73 using Rossi X-Ray Timing Explorer (RXTE) Proportional Counter Array and High Energy X-Ray Timing Experiment (HEXTE) data. The morphology of the double-p…