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Through observations and modeling, we demonstrate how the recently discovered large-scale bar in NGC 5248 generates spiral structure that continues from 10 kpc down to 100 pc. Deep inside the bar, two massive CO spirals with streaming motions of 20--40 km/s cover nearly 180 deg in azimuth and connect to two narrow K-band spirals which delineate the

We present the spatial distribution of chemical species in M 31, as derived from intermediate resolution spectra of seven B-type supergiants, lying within four OB associations, covering a galactocentric distance of 5 - 12 kpc. We do not detect any systematic oxygen gradient across this galactocentric range. We find that the inner regions of M 31

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Natural acceleration of charged particles occurs within a variety of physical contexts and through a range of physical processes.``Cosmic'' charged particle acceleration can involve particle energies and energy changes from less than one electron Volt (eV), and on through kilovolt (keV) energies, up to 1018 and perhaps 1020 eV. These acceleration

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