Search Publications
Completion of a Survey and Detailed Study of Double-peaked Emission Lines in Radio-loud Active Galactic Nuclei
Eracleous, Michael; Halpern, Jules P.
We report the completion of a survey of radio-loud active galactic nuclei (AGNs) begun in an earlier paper with the main goal of finding and studying broad, double-peaked Balmer lines. We present Hα spectra of 13 more broad-lined objects, including three with double-peaked Hα profiles. The final sample includes 106 radio-loud AGNs. In our final ce…
Discovery of X-Ray Quasi-periodic Oscillations from an Ultraluminous X-Ray Source in M82: Evidence against Beaming
Mushotzky, Richard F.; Strohmayer, Tod E.
We report the discovery with the European Photon Imaging Camera CCDs on board XMM-Newton of a 54 mHz quasi-periodic oscillation (QPO) in the greater than 2 keV X-ray flux from an ultraluminous X-ray source (ULX) in the starburst galaxy M82. This is the first detection of a QPO in the X-ray flux from an extragalactic ULX and confirms that the sourc…
On the Interaction between Convection and Magnetic Fields
Cattaneo, Fausto; Emonet, Thierry; Weiss, Nigel
Turbulent convection in the solar photosphere can act as a small-scale dynamo, maintaining a disordered magnetic field that is locally intense. On the other hand, convection is inhibited in the presence of a strong, externally imposed magnetic field, as for instance, in a sunspot. Large-scale, three-dimensional, numerical experiments on highly non…
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…
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…
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 …
Advanced Camera for Surveys Photometry of the Cluster RDCS 1252.9-2927: The Color-Magnitude Relation at z = 1.24
Ford, H. C.; Demarco, R.; Infante, L. +20 more
We investigate the color-magnitude (CM) relation of galaxies in the distant X-ray-selected cluster RDCS 1252.9-2927 at z=1.24 using images obtained with the Advanced Camera for Surveys on the Hubble Space Telescope in the F775W and F850LP bandpasses. We select galaxies based on morphological classifications extending about 3.5 mag down the galaxy …
Identification of Solar Sources of Major Geomagnetic Storms between 1996 and 2000
Zhang, J.; Bothmer, V.; Howard, R. A. +1 more
This paper presents identification of solar coronal mass ejection (CME) sources for 27 major geomagnetic storms (defined by disturbance storm timeindex<=-100 nT) occurring between 1996 and 2000. Observations of CMEs and their solar surface origins are obtained from the Large Angle and Spectrometric Coronagraph (LASCO) and the EUV Imaging Telesc…
The [C II] 158 Micron Line Deficit in Ultraluminous Infrared Galaxies Revisited
Lutz, D.; Genzel, R.; Sturm, E. +5 more
We present a study of the [C II] 157.74 µm fine-structure line in a sample of 15 ultraluminous infrared (IR) galaxies (IR luminosity LIR>=1012Lsolar ULIRGs) using the Long Wavelength Spectrometer (LWS) on the Infrared Space Observatory (ISO). We confirm the observed order of magnitude deficit (compared to …