No abstract

The Gum Nebula is 36°-wide shell-like emission nebula at a distance of only ∼450 pc. It has been hypothesized to be an old supernova remnant, fossil H II region, wind-blown bubble, or combination of multiple objects. Here we investigate the magneto-ionic properties of the nebula using data from recent surveys: radio-continuum data from the NRAO VLA and S-band Parkes All Sky Surveys, and a H data from the Southern H-Alpha Sky Survey Atlas. We model the upper part of the nebula as a spherical shell of ionized gas expanding into the ambient medium. We perform a maximum-likelihood Markov chain Monte Carlo fit to the NVSS rotation measure data, using the a H data to constrain average electron density in the shell n e . Assuming a latitudinal background gradient in rotation measure, we find = -+ -

285ChemInform Abstract The interchange between the 11-aryloxy-5,12-quinones (III) and the 12-aryloxy-5,11-quinones (IV) is dependent on the wavelength of the irradiation. Irradiation with λ = 300-480 nm effects formation of (IV), whereas on irradiation with λ > 510 nm (III) is recovered from (IV). Treatment of (III) with conc. H2SO4 affords (IV) as well.

Beschrieben wird die Synthese der N‐Acylaminoanthrachinone (II) sowie der Titelverbindungen (III) und (IV).

The title compounds (III), (IV) and (V) are prepared in order to compare the UV/ VIS absorptions of their solutions in benzene to those of heterocyclic Jt‐electronic analogues, i.e. phenoxyanthraceno‐ and naphthacenopyridines.