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The First IBIS/ISGRI Soft Gamma-Ray Galactic Plane Survey Catalog
Hill, A. B.; Walter, R.; Malaguti, G. +16 more
We report the first high-energy survey catalog obtained with the IBIS gamma-ray imager on board INTEGRAL. The analysis has been performed on the first-year Core Program ISGRI data comprising both Galactic Plane Scan and Galactic Centre Deep Exposure pointings for a total exposure time exceeding 5 Ms. This initial survey has revealed the presence o…
Abundances of Na, Mg and Al in nearby metal-poor stars
Zhao, G.; Liang, Y. C.; Shi, J. R. +2 more
To determine the population membership of nearby stars we explore abundance results obtained for the light neutron-rich elements 23Na and 27 Al in a small sample of moderately metal-poor stars. Spectroscopic observations are limited to the solar neighbourhood so that gravities can be determined from HIPPARCOS parallaxes, and …
The Globular Cluster Systems of the Early-Type Galaxies NGC 3379, NGC 4406, and NGC 4594 and Implications for Galaxy Formation
Zepf, Stephen E.; Rhode, Katherine L.
We have investigated the global properties of the globular cluster (GC) systems of three early-type galaxies: the Virgo Cluster elliptical NGC 4406, the field elliptical NGC 3379, and the field S0 galaxy NGC 4594. These galaxies were observed as part of a wide-field CCD survey of the GC populations of a large sample of normal galaxies beyond the L…
Solar and interplanetary sources of major geomagnetic storms during 1996-2002
Venkatakrishnan, P.; Srivastava, Nandita
During the 7-year period of the current solar cycle, 64 geoeffective coronal mass ejections (CMEs) were found to produce major geomagnetic storms (DST < -100 nT) at the Earth. In this paper we examine solar and interplanetary properties of these geoeffective coronal mass ejections (CMEs). The observations reveal that full-halo CMEs a…
An apparently normal γ-ray burst with an unusually low luminosity
Sunyaev, R. A.; Sazonov, S. Yu.; Lutovinov, A. A.
Much of the progress in understanding γ-ray bursts (GRBs) has come from studies of distant events (redshift z ~ 1). In the brightest GRBs, the γ-rays are so highly collimated that the events can be seen across the Universe. It has long been suspected that the nearest and most common events have been missed because they are not as collimated or the…
Band-splitting of coronal and interplanetary type II bursts. III. Physical conditions in the upper corona and interplanetary space
Magdalenić, J.; Vršnak, B.; Zlobec, P.
We analyse properties of 58 type II radio bursts recorded in the meter-to-kilometer wavelength range, focusing on episodes of band-split emission. The basic two parameters utilized are the frequency drift Df=df/dt and the relative band-split BDW=Δ f/f of type II burst emission lanes. On average, in the meter-to-kilometer wavelength rang…
Observational Consequences of a Magnetic Flux Rope Emerging into the Corona
Gibson, S. E.; Fan, Y.; Mandrini, C. +2 more
We show that a numerical simulation of a magnetic flux rope emerging into a coronal magnetic field predicts solar structures and dynamics consistent with observations. We first consider the structure, evolution, and relative location and orientation of S-shaped, or sigmoid, active regions and filaments. The basic assumptions are that (1) X-ray sig…
Mid-infrared emission of galactic nuclei. TIMMI2 versus ISO observations and models
Siebenmorgen, R.; Krügel, E.; Spoon, H. W. W.
We investigate the mid-infrared radiation of galaxies that are powered by a starburst or by an AGN. For this end, we compare the spectra obtained at different spatial scales in a sample of infrared bright galaxies. ISO observations which include emission of the nucleus as well as most of the host galaxy are compared with TIMMI2 spectra of the nucl…
Geometry of the non-thermal emission in SN 1006. Azimuthal variations of cosmic-ray acceleration
Ballet, J.; Decourchelle, A.; Ferrando, P. +3 more
On the Relation between Filament Eruptions, Flares, and Coronal Mass Ejections
Xu, Yan; Yang, Guo; Jing, Ju +2 more
We present a statistical study of 106 filament eruptions, which were automatically detected by a pattern recognition program implemented at Big Bear Solar Observatory using Hα full-disk data from 1999 to 2003. We compare these events with Geostationary Operational Environmental Satellite soft X-ray time profiles, solar-geophysical data (SGD) solar…