Search Publications
Ion energy equation for the high-speed solar wind: Ulysses observations
Balogh, A.; McComas, D. J.; Goldstein, B. E. +4 more
Ulysses data in the high-speed solar wind that cover a wide range of latitudes centered on the solar poles were studied to test whether a polytrope law can be used to close the ion energy equation. Three approaches were taken. We determined the correlation between proton temperature and density (1) in the free expansion of the high-speed solar win…
A pair of forward and reverse slow-mode shocks detected by Ulysses at ∼5 AU
Lakhina, G. S.; Tsurutani, B. T.; Smith, E. J. +6 more
We report the first finding of a pair of forward and reverse slow-mode shocks in the distant heliosphere using plasma and magnetic field data from the Ulysses spacecraft located at 5.3 AU and 9°S heliolatitude. The slow-mode shocks are found to occur in a compressed magnetic field (low plasma ) region within a co-rotating interaction region (CIR).…
EUV Spectroscopy of the Sunspot Region NOAA 7981 Using SOHO - II. Velocities and Line Profiles
Harrison, R. A.; Wilhelm, K.; Fredvik, T. +8 more
We have studied the dynamics in the sunspot transition region between the chromosphere and the corona and investigated the extension of the flow field into the corona. Based on EUV spectra of a medium size sunspot and its surroundings, NOAA 7981, observed with CDS and SUMER on SOHO, we derive line-of-sight velocities and study the line profiles fo…
ISOCAM Mid-Infrared Imaging of the Quiescent Spiral Galaxy NGC 7331
Smith, Beverly J.
Using the mid-infrared camera (ISOCAM) on the Infrared Space Observatory (ISO), the Sb LINER galaxy NGC 7331 has been imaged in two broadband and four narrowband filters between 6.75 and 15 µm. These maps show a prominent circumnuclear ring of radius 0.25 arcmin × 0.75 arcmin (1.1 × 3.3 kpc) encircling an extended central source. The 7.7 and…
Deep Optical Imaging of the Bright Seyfert Galaxy NGC 5548: A Long, Very Low Surface Brightness Tail
Glazebrook, Karl; Tyson, J. Anthony; Fischer, Philippe +9 more
Deep Hubble Space Telescope Wide Field Camera (WFC-1) imaging of a region 3.7‧ east of the V = 13 mag Seyfert galaxy NGC 5548 in the F555W and F785LP bands, and deep ground-based V and I imaging, show a new extended, blue, low surface brightness structure, apparently a remnant of a tidal interaction associated with NGC 5548. If this straight, low …
A search for substellar companions around nine weak-lined T-Tauri stars with the Planetary Camera 2 of the Hubble Space Telescope
Torres, Guillermo; Latham, David W.; Sartoretti, Paola +1 more
To search for substellar companions, we have obtained I-band images of 9 weak-lined T-Tauri stars in the Taurus-Auriga star-forming region using the Planetary Camera 2 of the Hubble Space Telescope. Except for a stellar companion close to HBC 407, we found no companions within 8arcsec of any of our targets. We did find 23 faint objects outside a s…
The Identification and Characterization of Alfvénic Fluctuations in ULYSSES Data at Midlatitudes
Balogh, A.; Lucek, E. A.
Ulysses magnetic field and plasma data recorded during 1992 and 1993 as the spacecraft moved through mid-heliolatitudes, have been used to identify intervals dominated by Alfvénic fluctuations in the presence of corotating interaction regions. A wavelet frame representation of Elsässer variables was used to calculate the Alfvénicity of the fluctua…
Doppler imaging of stellar surface structure. VIII. The effectively single and rapidly-rotating G8-giant HD 51066 = CM Camelopardalis
Strassmeier, K. G.; Weber, M.; Washuettl, A. +2 more
We present first Doppler images of HD 51066 from observations in 1994, 1995, 1996 and 1997, and find evidence for a vanishing polar spot in accordance with the system's long-term brightness increase. Several small spots with Delta T~500 K appear also at low latitudes. Our cross-correlation maps indicate a latitude-dependent phase-shift pattern bet…
SUMER Observations of the Evolution and the Disappearance of a Solar Prominence
Kucera, T. A.; Ofman, L.; Mouradian, Z. +1 more
The mechanisms that lead to the formation and the disappearance of prominences are poorly understood, at present. An arch-shaped prominence was observed with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on board the Solar and Heliospheric Observatory (SOHO) on 31 March-1 April 1996. The observations were performed a…
The Ages of Disturbed Field Elliptical Galaxies. II. Central Properties
Silva, David R.; Bothun, Gregory D.
The formation of elliptical galaxies via the merger of gas-rich disks has received considerable attention in recent years, with many studies strongly supporting the merger hypothesis. When investigated in detail, the dynamics of a major merger that produces a high phase-space density of material (e.g., the center of an elliptical galaxy) invariabl…