Search Publications
The relationship of coronal mass ejections to streamers
Howard, R. A.; Dere, K. P.; Subramanian, Prasad +1 more
We have examined images from the Large-Angle and Spectrometric Coronagraph (LASCO) to study the relationship of coronal mass ejections (CMEs) to coronal streamers. We wish to test the suggestion [Low, 1996] that CMEs arise from flux ropes embedded in a streamer erupting and disrupting the streamer. The data span a period of 2 years near Sunspot mi…
Observation of Injection and Pre-Acceleration Processes in the Slow Solar Wind
Gloeckler, George
Knowledge of injection and pre-acceleration mechanisms of ions is of fundamental importance for understanding particle acceleration that takes place in various astrophysical settings. The heliosphere offers the best chance to study these poorly understood processes experimentally. We examine ion injection and pre-acceleration using measurements of…
Kinematic Measurements of Polar Jets Observed by the Large-Angle Spectrometric Coronagraph
Howard, R. A.; Wood, B. E.; Karovska, M. +2 more
We analyze polar jets observed by the Large-Angle Spectrometric Coronagraph (LASCO) instrument aboard the Solar and Heliospheric Observatory. The events studied here are from 1997 March 24 and August 5. The main objective of our analysis is to determine whether the jets' motions are consistent with ballistic behavior. Although ballistic trajectori…
A new radio double lens from CLASS: B1127+385
Pearson, T. J.; Blandford, R. D.; Koopmans, L. V. E. +9 more
We present the discovery of a new gravitational lens system with two compact radio images separated by 0.701 +/- 0.001 arcsec. The lens system was discovered in the Cosmic Lens All Sky Survey (CLASS) as a flat-spectrum radio source. Both radio components show structure in a Very Long Baseline Array (VLBA) 8.4-GHz radio image. No further extended s…
Interstellar C_2 absorption lines towards CH+ forming regions
Gredel, R.
Interstellar C_2 absorption line observations towards the southern OB associations NGC 2439, Vela OB1, and Cen OB1 are used to infer gaskinetic temperatures Tkin and densities nc towards lines of sight with previously determined large CH and CH+ column densities. Towards NGC 2439, the material is characterised by t…
The Lyα Forest of the Quasar in the Hubble Deep Field South
Ferguson, H. C.; Carollo, C. M.; Stiavelli, M. +8 more
The quasar in the Hubble Deep Field South (HDF-S), J2233-606 (zem=2.23), has been observed exhaustively by ground-based telescopes and by the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope at low, medium, and high resolution in the spectral interval from 1120 to 10000 Å. The combined data give continuous covera…
The Magnetic Association of Coronal Bright Points
Preś , Paweł; Phillips, Kenneth H. J.
Several coronal bright points identified in a quiet region of the Sun from Solar and Heliospheric Observatory/Extreme-Ultraviolet Imaging Telescope Fe XII images are found to have a time evolution from birth to decay that is extremely well correlated with the rise and fall of magnetic flux as determined from photospheric magnetograms made with the…
The Bordeaux and Valinhos CCD meridian circles
Teixeira, R.; Colin, J.; Mazurier, J. M. +14 more
A first CCD 512x 512 camera working in scan mode (declination field 14') was mounted in 1994 on the Bordeaux CCD meridian circle. After a testing period, this camera was installed on the Valinhos CCD meridian circle (near S\ ao Paulo, Brazil), as part of a collaboration between Bordeaux Observatory and the Instituto Astronomico e Geofisico of S\ a…
Discovery of a Remarkable Point-Symmetric Proto-Planetary Nebula: Hubble Space Telescope Imaging of IRAS 04296+3429
Sahai, Raghvendra
We present images of the proto-planetary nebula (PPN) IRAS 04296+3429 (hereafter I04296) taken with the Hubble Space Telescope Wide Field Planetary Camera 2 in two wide-band filters centered at 0.56 and 0.81 µm. We find that this object, which belongs to a class of carbon-rich PPNs with a peculiar 21 µm dust emission feature, has a str…
Cyclotron resonance in coronal holes: 2. A two-proton description
Hollweg, Joseph V.
In a cold plasma, the ion-cyclotron mode does not extend above the proton cyclotron frequency. As a consequence, for waves propagating outward from the Sun, only protons that are moving slower than the mean proton wind speed can resonate with this mode. Thus only roughly half of the proton distribution function can be in resonance at any instant o…