Search Publications
The Double Structure of the Coronal Streamer Belt
Eselevich, M. V.; Eselevich, V. G.
Increasing the effective spatial resolution when analyzing LASCO-C2/SOHO data helped to reveal the existence of double-ray structure in the streamer belt, both in the absence and presence of belt bends. Streamer-belt rays located in the plane of the sky are demonstrated to deviate poleward (north- and southward, respectively, in the N and S hemisp…
Cross-Scale Coupling Within Rolled-Up MHD-Scale Vortices and Its Effect on Large Scale Plasma Mixing Across the Magnetospheric Boundary
Hasegawa, H.; Fujimoto, M.; Nakamura, T. K. M.
Kelvin-Helmholtz Instability (KHI) is an MHD-scale instability that grows in a velocity shear layer such as the low-latitude boundary layer of the magnetosphere. KHI is driven unstable when a velocity shear is strong enough to overcome the stabilization effect of magnetic field. When the shear is significantly strong, vortices in the nonlinear sta…
MERLIN Astrometry of 11 Radio Stars
Garrington, Simon T.; Fey, Alan L.; Boboltz, David A. +3 more
We report accurate positions in the International Celestial Reference Frame (ICRF) for 11 radio stars. Observations were made using the Multi-Element Radio Linked Interferometer Network at a radio frequency of 5 GHz. The positions are estimated to be accurate at the 5 mas level. Positions were obtained directly in the ICRF by phase referencing the…
Objective CME detection over the solar cycle: A first attempt
Berghmans, D.; Robbrecht, E.; van der Linden, R. A. M.
We recently developed a software package to autonomously detect coronal mass ejections (CMEs) in image sequences from large angle spectrometric coronagraph (LASCO). The detection is not done in the original images, instead we detect bright ridges in (time, height) plots using a modified version of the Hough transform. Experimental results on real-…
Near-Ultraviolet Sources in the Great Observatories Origins Deep Survey Fields
Gardner, Jonathan P.; Grogin, N. A.; Dahlen, T. +1 more
We present an ultraviolet-selected sample of 268 objects in the two fields of the Great Observatories Origins Deep Survey (GOODS). We used the parallel observations taken with the Wide Field Planetary Camera 2 in the U band (F300W), which covered 88% of the GOODS fields, to identify sources and selected only objects with GOODS Advanced Camera for …
Multiwavelength Analysis of an Active Region
Vial, J. -C.; Gontikakis, C.; Nindos, A. +4 more
We study active region NOAA 8541, observed with instruments on board SOHO, as well as with TRACE. The data set mainly covers the transition region and the low corona. In selected loops studied with SUMER on SOHO, the VIII 770 Å line is systematically redshifted. In order to estimate the plasma velocity, we combine the Doppler shifts with proper mo…
Variable Stars in the Large Magellanic Cloud: Discovery of Extragalactic W UMa Binaries
Rucinski, Slavek M.; Kaluzny, Janusz; Mochnacki, Stefan
We observed a field in the disk of the LMC on two consecutive nights in search of rapid variable stars. We found two pulsating stars of type RRab and δ Scuti and four binary stars; among the latter we found one sdB or cataclysmic variable below the LMC blue main sequence and three very close binary systems on the main sequence. At least one of the…
Quiet Sun Contribution to Variations in the Total Solar Irradiance
Withbroe, George L.
An analysis of spatially-resolved measurements of the intensity of the photospheric continuum by the Michelson Doppler Imager (MDI) on the SOHO spacecraft indicates that these data can be used to study variations of the Total Solar Irradiance (TSI). Since the techniques employed depend upon ratios of intensities measured by MDI, they are independe…
Stellar structure of the dwarf irregular galaxy DDO 216
Tikhonov, N. A.
Observations with the 6-mBTA telescope and archival Hubble Space Telescope data were used for the photometry of stars in the dwarf edge-on irregular galaxy DDO 216 (Peg DIG). We determined the change in the number density of stars of various ages along the major and minor axes of the galaxy. We found that the young stars of the galaxy concentrate …
The Relationship Between Baryons and Dark Matter in Extended Galaxy Halos
Stocke, J. T.; Putman, M. E.; Rosenberg, J. L. +1 more
The relationship between gas-rich galaxies and Lyα absorbers is addressed in this paper in the context of the baryonic content of galaxy halos. Deep Arecibo H I observations are presented of two gas-rich spiral galaxies within 125 h-170 kpc projected distance of a Lyα absorber at a similar velocity. The galaxies investigated …