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On the Magnetic Energy Avalanche in the Solar Atmosphere
Tarbell, T. D.; Ryutova, M. P.
We discuss a mechanism of energy production associated with the acoustic and MHD shocks produced by colliding and reconnecting flux tubes and present the observational results showing a connection between the dynamic changes in the photosphere and the high velocity and heating events in the transition region. We suggest that these processes may pr…
Recurrent Cosmic Ray Decreases During the Second Ulysses orbit. COSPIN/KET results.
Kunow, H.; Heber, B.; Ferrando, P. +5 more
The recurrent cosmic ray decreases, their evolution with heliolatitude, the rigidity dependence of their amplitude and their relation with the Corotating Interaction Regions have been extensively studied during the first Ulysses orbit. These studies are mainly concentrated in south heliographic latitudes under conditions close to Solar minimum. In…
Single Channel Photoelectric Photometry of RZ Arietis, 1983-2001
Thompson, Raymond R.
The AAVSO Photoelectric Photometry Archives contain 568 V observations of the SRb star RZ Ari covering 17 years. During this time, there are 22 clearly defined cycles evident in the data, ranging from 26 to 71 days and giving an average period of 51.32 days. Assuming a V magnitude of 5.87 for the comparison star, RZ Ari varied from 5.45 to 6.19, g…
Is There an Age of the Universe Problem after the Hipparcos Data?
Özer, Murat
We have reanalyzed the age of the universe problem under the assumption that the lower limit on the age of the globular clusters is ∼11 Gyr, as predicted by the recent Hipparcos data. We find that the globular cluster and the expansion ages in a standard l=0 universe are consistent only if the present value H0 of the Hubble constant is …
Solar energetic proton intensity profiles at 5 AU from the Sun
Balogh, A.; Heber, B.; McKibben, R. B. +2 more
We compare Ulysses particle measurements for two large gradual solar energetic particle (SEP) events, which took place on 24 August 1998 and 20 January 1999. At these times the Ulysses spacecraft was close to the ecliptic plane and at ∼5.2 AU from the Sun. The two events are characterised by similar time intensity profiles for 40-100 MeV protons, …
Solar large-scale emitting chains: Preliminary remarks on the cycle variability
Chertok, I. M.
Preliminary remarks on the solar cycle phase variability of the microwave and EUV large-scale chains are outlined briefly based on the Nobeyama Radioheliograph and SOHO/EIT data. The observed complication of the chains in the course of the cycle appears to reflect the corresponding complication of the global solar magnetosphere.
Ulysses observations of solar energetic particles to high heliographic latitudes
Giacalone, J.; McKibben, R. B.; Zhang, M. +3 more
At the time of the flare on the Bastille Day of 2000, Ulysses spacecraft was at 3.17 AU from the sun, high heliographic latitude of 62° South, and 116° in longitude east of the Earth. The event produced large fluxes of energetic particles up to energies >100 MeV at both Ulysses and the Earth. Enhancements of energetic particles were immediately…
Gravitational Microlensing of Giant Luminous Arcs: a Test for Compact Dark Matter in Clusters of Galaxies
Lewis, Geraint F.
The true nature of dark matter in the universe still eludes us. This paper discusses a new test for the detection of stellar mass compact dark matter in galaxy clusters by observing its gravitational lensing influence on the surface brightness of giant luminous arcs. If dark matter is in the form of stellar mass compact objects, then the extremes …
The Dust Content and Opacity of Actively Star-forming Galaxies
Calzetti, Daniela; Storchi-Bergmann, Thaisa; Bohlin, Ralph C. +3 more
We present far-infrared (FIR) photometry at 150 and 205 µm of eight low-redshift starburst galaxies obtained with the Infrared Space Observatory (ISO) ISOPHOT. Five of the eight galaxies are detected in both wave bands, and these data are used, in conjunction with IRAS archival photometry, to model the dust emission at λ>~40 µm. The…
On the Absorption of X-Rays in the Interstellar Medium
McCray, R.; Wilms, J.; Allen, A.
We present an improved model for the absorption of X-rays in the interstellar medium (ISM) intended for use with data from future X-ray missions with larger effective areas and increased energy resolution such as Chandra and the X-Ray Multiple Mirror mission, in the energy range >~100 eV. Compared with previous work, our formalism includes rece…