Abstract. The structure of supergiant shells, in particular of LMC 4, is hard to explain with stochastic selfpropagating star formation. A series of supergiant structures lies along the outer edge of the LMC and form a sequence increasing clockwise in age. We have considered the rotation of the LMC and its motion through the halo of the Milky Way and propose that these structures find their origin in star formation induced in the bow-shock formed at the leading edge of the LMC. Due to the rotation of the LMC these structures then move aside.
Abstract. We present the first proper motion study of M 10 (NGC 6254). Absolute proper motions of about 532 stars in the field of the globular cluster M 10 were determined with respect to Hipparcos and ACT reference stars. In addition to photographic plates of Bonn and Shanghai also wide field CCD observations as second epoch plates were used. The wide field CCD observations show an accuracy comparable to that of the photographic plates. A good coincidence of the solutions based on reference stars from Hipparcos and from ACT was found. Our final proper motions allow a sufficient separation of cluster and field stars. Two population II Cepheids were confirmed to be members of M 10. The absolute proper motion of M 10 was determined and combined with its distance from the Sun and its radial velocity. The space motion and metallicity of M 10 indicates the characteristics of a halo object with an orbit reaching to a maximal z-distance of less than 3 kpc.
Resultsof a ground-based optical monitoring campaign on 3C 390.3 in 1994-95 are presented. The broad-band fluxes (B, V , R, and I), the spectrophotometric optical continuum flux F λ (5177Å), and the integrated emission-line fluxes of Hα, Hβ, Hγ, He i λ5876, and He ii λ4686 all show a nearly monotonic increase with episodes of milder short-term variations superposed. The amplitude of the continuum variations increases with decreasing wavelength (4400 -9000Å). The optical continuum variations follow the variations in the ultraviolet and X-ray with time delays, measured from the centroids of the cross-correlation functions, typically around 5 days, but with uncertainties also typically around 5 days; zero time delay between the high-energy and low-energy continuum variations cannot be ruled out. The strong optical emission lines Hα , Hβ , Hγ , and He i λ5876 respond to the high-energy continuum variations with time delays typically about 20 days, with uncertainties of about 8 days. Thereis some evidence that He ii λ4686 responds somewhat more rapidly, with a time delay of around 10 days, but again, the uncertainties are quite large (∼ 8 days).The mean and rms spectra of the Hα and Hβ line profiles provide indications for the existence of at least three distinct components located at ±4000 and 0 km s −1 relative to the line peak. The emission-line profile variations are largest near line center.
The IceCube Observatory has collected over 577 billion cosmic-ray induced muon events in its final configuration from May 2011 to May 2020. We used this data set to provide an unprecedented statistically accurate map of the cosmic ray arrival direction distribution in the TeV-PeV energy range scale in the Southern Hemisphere. Such an increase in event statistics makes it possible to extend the sensitivity to anisotropies at higher cosmic ray energies and smaller angular scales. It will also facilitate a more detailed assessment of the observatory stability over both short-and long-time scales. This will enable us to study the time variability of the cosmic ray anisotropy on a yearly-base and over the entire data sample period covering most of the solar cycle 24. We present the preliminary results from the study with the extended event sample.
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