Search Publications
SOHO/CDS observations of waves above the network
Curdt, W.; Rybák, J.; Gömöry, P. +2 more
We analyze temporal variations in the intensities and the Doppler shifts of He i 584.33 Å (chromosphere), O v 629.73 Å (transition region), and Mg ix 368.07 Å (corona) measured in and above chromospheric network near disk center with the Coronal Diagnostic Spectrometer (CDS) onboard the Solar and Heliospheric Observatory (SOHO). There is significa…
CCD Speckle Observations of Binary Stars from the Southern Hemisphere. IV. Measures during 2001
Horch, Elliott P.; Franz, Otto G.; Baptista, Brian J. +1 more
We present 549 observations of 181 primarily southern binary stars. Of these, 32 are high-quality nondetections, meaning that, if binary, the system had a separation below the diffraction limit at the time of the observation, and relative astrometry is presented for the remaining 517 observations. In addition, a magnitude difference measure is rep…
Encounters of the dust trails of comet 45P/Honda-Mrkos-Pajdusakova with Venus in 2006
Christou, A. A.; Vaubaillon, J.
Aims.We aim to investigate the dynamical fate of meteoroids ejected during past perihelion passages of comet 45P/Honda-Mrkos-Pajdusakova that intersect the orbit of Venus. Of particular interest is the possibility, borne of previous work, that a significant flux of these particles will reach the planet during early June and late August 2006, when …
A 110 MG cyclotron harmonic in the optical spectrum of RX J1554.2+2721
Szkody, P.; Schreiber, M. R.; Schwope, A. D.
We report the detection of a 110 MG cyclotron harmonic in the SDSS-spectrum of the magnetic cataclysmic variable (MCV) RX J1554.2+2721. This feature was noted earlier by others but remained unexplained. The wide spectral coverage of the new spectrum together with the earlier detection of a Zeeman split Lyα line in a field of 144 MG makes the ident…
Identification of a new short-period comet near the sun
Hönig, S. F.
We present the identification of comet C/1999 R1 (SOHO) with comet C/2003 R5 (SOHO). Both apparitions were only observed with the Solar and Heliospheric Observatory (SOHO) at distances smaller than 0.1 AU from the sun with the LASCO coronagraphs onboard the spacecraft. Although SOHO comets usually have poor orbital coverage, the 1999 and 2003 arcs…
A statistical study of SUMER spectral images: events, turbulence, and intermittency
Vial, J. -C.; Lemaire, P.; Buchlin, E.
We analyze a series of full-Sun observations performed with the SoHO/SUMER instrument between March and October 1996. Some parameters (radiance, shift and width) of the S vi 93.3 nm , S vi 94.4 nm , and Ly \varepsilon line profiles were computed on board. Radiances and line-of-sight velocities in a large central region of the Sun are studied stati…
On the structure of field-aligned currents in the mid-altitude cusp
Fazakerley, A. N.; Owen, C. J.; Marchaudon, A. +3 more
We analyse two crossings of the polar cusp at mid-altitudes (≈4 RE) by Cluster in order to study the structure of field-aligned currents associated with the injection of magnetosheath plasma. The current density is deduced independently from magnetic field and from particle flux measurements. In both cases the data are carefully tested.…
Helioseismic sensing of the solar cycle
Howe, R.; Komm, R.; Hill, F.
All quantities observed with helioseismic methods, such as frequencies, width, and amplitudes of acoustic waves, vary with the solar cycle. However, they relate to the dynamics and structure in different parts of the solar convection zone. The rotation rate varies with the solar cycle, showing the so-called torsional oscillation pattern, from the …
Lyα Absorption in the Quasar Triplet Q0107-025A, Q0107-025B, and Q0107-0232: Data Calibration and Line Selection
Impey, C. D.; Petry, C. E.; Foltz, C. B. +1 more
We present spectroscopic observations for quasars Q0107-025A, Q0107-025B, and Q0107-0232. For the first time, all data obtained with the Hubble Space Telescope's GHRS and FOS for these three quasars are combined. Lyα absorbers selected from the spectra can be used to trace the coherence of the intergalactic medium (IGM) on scales of 1-2 h-1
The Warped Nuclear Disk of Radio Galaxy 3C 449
Baum, Stefi A.; O'Dea, Christopher P.; Sparks, William B. +11 more
Among radio galaxies containing nuclear dust disks, the bipolar jet axis is generally observed to be perpendicular to the disk major axis. The FR I radio source 3C 449 is an outlier to this statistical majority, as it possesses a nearly parallel jet/disk orientation on the sky. We examine the 600 pc dusty disk in this galaxy with images from the H…