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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 …
G0.570-0.018: A Young Supernova Remnant? INTEGRAL and VLA Observations
Terrier, R.; Renaud, M.; Bykov, A. M. +4 more
We report INTEGRAL IBIS γ-ray and VLA radio observations of G0.570-0.018, a diffuse X-ray source recently discovered by ASCA and Chandra in the Galactic center region. Based on its spectrum and morphology, G0.570-0.018 has been proposed to be a very young supernova remnant. In this scenario, the presence of γ-ray lines coming from the short-lived …
The possible detection of high-redshift Type II QSOs in deep fields
Meiksin, Avery
The colours of high-redshift Type II quasi-stellar objects (QSOs) are synthesized from observations of moderate-redshift systems. It is shown that Type II QSOs are comparable to starbursts at matching the colours of z850-dropouts and i775-drops in the Hubble UltraDeep Field, and more naturally account for the bluest objects d…
Corrections of Proper Motions in Declination By Using ILS Data
Damljanovic, G.; Pejovic, N.
There are nowadays numerous astrometric ground--based observations of some stars referred to Hipparcos Catalogue, made at many observatories during the last century. We used the data on latitude variations, covering the period 1899.7 -- 1979.0, of visual Zenith Telescopes (ZT) of International Latitude Service (ILS), to improve the Hipparcos prope…