Search Publications
Missions
Journals
Publication Years
8-13 µm Spectroscopy of Young Stellar Objects: Evolution of the Silicate Feature
Meyer, Michael R.; Hillenbrand, Lynne A.; Blake, Geoffrey A. +1 more
Silicate features arising from material around pre-main-sequence stars are useful probes of the star and planet formation process. In order to investigate possible connections between dust processing and disk properties, 8-13 µm spectra of 34 young stars, exhibiting a range of circumstellar environments and including spectral types A-M, were…
Complex X-Ray Absorption and the Fe Kα Profile in NGC 3516
Turner, T. J.; Kraemer, S. B.; Reeves, J. N. +2 more
We present data from simultaneous Chandra, XMM-Newton, and BeppoSAX observations of the Seyfert 1 galaxy NGC 3516, taken during 2001 April and November. We have investigated the nature of the very flat observed X-ray spectrum. Chandra grating data show the presence of X-ray absorption lines, revealing two distinct components of the absorbing gas, …
Self-Consistent Magnetohydrodynamic Modeling of a Coronal Mass Ejection, Coronal Dimming, and a Giant Cusp-shaped Arcade Formation
Shibata, Kazunari; Chen, P. F.; Isobe, Hiroaki +3 more
We performed magnetohydrodynamic simulations of coronal mass ejections (CMEs) and associated giant arcade formations, and the results suggest new interpretations of observations of CMEs. We performed two cases of the simulation: with and without heat conduction. Comparing between the results of the two cases, we found that the reconnection rate in…
Multifractal Analysis Of Solar Magnetograms
Abramenko, Valentyna I.
As solar observational techniques improve, fine small-scale structures observed on the solar surface become more pronounced. Complex filigree structures of solar granulation, sunspots, photospheric magnetic and velocity fields cannot be described adequately by a single parameter (e.g., filling factor, fractal dimension, or power-law index). Method…
The WEBT campaign to observe AO 0235+16 in the 2003-2004 observing season. Results from radio-to-optical monitoring and XMM-Newton observations
Lähteenmäki, A.; Papadakis, I. E.; Smith, N. +64 more
A multiwavelength campaign to observe the BL Lac object
The NGC 5846 Group: Dynamics and the Luminosity Function to MR=-12
Mahdavi, Andisheh; Tully, R. Brent; Trentham, Neil
We conduct a photometric and spectroscopic survey of a 10 deg2 region surrounding the nearby NGC 5846 group of galaxies, using the Canada-France-Hawaii and Keck I telescopes to study the population of dwarf galaxies as faint as MR=-10. Candidates are identified on the basis of quantitative surface brightness and qualitative m…
Plasma sheet formation during long period of northward IMF
Phan, Tai D.; Øieroset, Marit; Raeder, Joachim +2 more
We have studied the entry paths of solar wind plasma into the magnetosphere during an extended period of northward IMF using an OpenGGCM MHD simulation of the cold dense plasma sheet (CDPS) event observed on October 23, 2003 by the Cluster spacecraft. We find that high-latitude reconnection occurs tailward of both cusps between the IMF and geomagn…
Discovery of a Primitive Damped Lyα Absorber near an X-Ray-bright Galaxy Group in the Virgo Cluster
Bowen, David V.; Tripp, Todd M.; Jenkins, Edward B. +3 more
We present a new ultraviolet echelle spectrum of PG 1216+069, obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, that reveals damped Lyα absorption, as well as O I, C II, Si II, and Fe II absorption lines, at zabs=0.00632 near the NGC 4261 galaxy group in the periphery of the Virgo Cluster. The a…
The Optical and Ultraviolet Spectral Energy Distributions of Short-Period Black Hole X-Ray Transients in Outburst
Hynes, R. I.
We compile optical and UV spectra of a sample of ``typical'' short-period black hole X-ray transients in outburst. We also survey determinations of interstellar extinction and distance to deredden spectra and compare absolute fluxes. Hence, we perform a comparative study of the broadband spectral energy distributions (SEDs). We find that, given su…
The Stellar Populations in the Central Parsecs of Galactic Bulges
Filippenko, Alexei V.; Ho, Luis C.; Shields, Joseph C. +5 more
We present Hubble Space Telescope blue spectra at intermediate spectral resolution for the nuclei of 23 nearby disk galaxies. These objects were selected to have nebular emission in their nuclei and span a range of emission-line classifications, as well as Hubble types. In this paper we focus on the stellar population as revealed by the continuum …