Search Publications
Missions
Journals
Publication Years
Plasma temperatures in Saturn's ionosphere
Galand, Marina; Moore, Luke; Yelle, Roger +2 more
We have calculated self-consistent electron and ion temperatures in Saturn's ionosphere using a series of coupled fluid and kinetic models developed to help interpret Cassini observations and to examine the energy budget of Saturn's upper atmosphere. Electron temperatures in the midlatitude topside ionosphere during solar maximum are calculated to…
The directivity of solar type III bursts at hectometer and kilometer wavelengths: Wind-Ulysses observations
Maksimovic, M.; Bonnin, X.; Hoang, S.
We investigate the directivity of solar type III radio bursts at hectometer and kilometer wavelengths using radio data recorded simultaneously by the Wind and Ulysses spacecraft which are widely separated in heliocentric longitude and latitude. From the positions of the associated flares and the solar wind speed and plasma density measured aboard …
Isolated OB Associations in Stripped H I Gas Clouds
Freeman, K. C.; Ryan-Weber, E. V.; Oey, M. S. +4 more
HST ACS HRC images in UV (F250W), V (F555W), and I (F814W) resolve three isolated OB associations that lie up to 30 kpc from the stellar disk of the S0 galaxy NGC 1533. Previous narrowband Hα imaging and optical spectroscopy showed these objects as unresolved intergalactic H II regions having Hα luminosities consistent with single early-type O sta…
Extending the baseline: Spitzer mid-infrared photometry of globular cluster systems in the Centaurus A and Sombrero Galaxies
Spitler, Lee R.; Forbes, Duncan A.; Beasley, Michael A.
Spitzer IR Array Camera (IRAC) mid-infrared photometry is presented for the globular cluster (GC) systems of the NGC 5128 (`Centaurus A') and NGC 4594 (`Sombrero') galaxies. Existing optical photometric and spectroscopic are combined with this new data in a comprehensive optical-to-mid-IR colour catalogue of 260 GCs. Empirical colour-metallicity r…
First observations of SO2 above Venus' clouds by means of Solar Occultation in the Infrared
Montmessin, F.; Fedorova, A.; Korablev, O. +6 more
Solar Occultation in the Infrared (SOIR) is a part of the Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV)/SOIR occultation experiment on board Venus Express dedicated to the study of gaseous and aerosol vertical structure of Venus' mesosphere. SOIR is an echelle spectrometer with acoustooptic selection of diff…
Multiscale Analysis of Active Region Evolution
Maguire, K.; Gallagher, P. T.; Young, C. A. +4 more
Flows in the photosphere of solar active regions are turbulent in nature. Because magnetic fields are frozen into the plasma on the solar surface, magnetograms can be used to investigate the processes responsible for structuring active regions. Here, a continuous wavelet technique is developed, analyzed, and used to investigate the multiscale stru…
Observations of Doppler Shift Oscillations with the EUV Imaging Spectrometer on Hinode
Warren, Harry P.; Watanabe, Tetsuya; Mariska, John T. +1 more
Damped Doppler shift oscillations have been observed in emission lines from ions formed at flare temperatures with the Solar Ultraviolet Measurements of Emitted Radiation spectrometer on the Solar and Heliospheric Observatory and with the Bragg Crystal Spectrometer on Yohkoh. This Letter reports the detection of low-amplitude damped oscillations i…
Damping of Slow MHD Coronal Loop Oscillations by Shocks
Verwichte, E.; Haynes, M.; Arber, T. D. +1 more
The damping of slow magnetoacoustic coronal loop oscillations by shock dissipation is investigated. Observations of large-amplitude slow-mode observations made by SUMER show a clear dependency of the damping rate on the oscillation amplitude. Fully nonlinear MHD simulations of slow-mode oscillations in the presence of thermal conduction are perfor…
GALEX Spectroscopy of SN 2005ay Suggests Ultraviolet Spectral Uniformity among Type II-P Supernovae
Smith, G. P.; Gal-Yam, A.; Kirshner, R. P. +24 more
We present the initial results from our GALEX program designed to obtain ultraviolet (UV) spectra of nearby core-collapse supernovae (SNe). Our first target, SN 2005ay in the nearby galaxy NGC 3938, is a typical member of the SN II-P subclass. Our spectra show remarkable similarity to those of the prototypical Type II-P SN 1999em, and resemble als…
Analysis of Interplanetary Coronal Mass Ejection Parameters as a Function of Energetics, Source Location, and Magnetic Structure
Reinard, A. A.
We describe a study of how ICME parameters vary as function of source location, associated flare magnitude, and magnetic structure. The strongest compositional enhancements are found to occur in events originating in central longitudes of the Sun, those with large associated flares, and those that are identified as magnetic clouds. In situ velocit…