Local gas without reddening - The contribution of stray radiation to 21 centimeter line measurements

Le résumé fourni par la source

The question of 'zero offset' in the relationship between gas and dust is considered. Recent studies comparing reddenings with H I column densities, N(H I), derived from 21 cm line data find that, instead of a simple proportionality, the relation is N(H I) = Z(1) + Z(2) x E(B-V) with a positive value of Z(1), a positive zero offset. On the other hand, studies that derive H I column densities from UV measurements of the Ly-alpha line find a zero, or a very small negative value for Z(1). The radio observers have been unable to state with certainty that their zero offsets are real. The offsets may have arisen from a specific instrumental effect, namely the reception of radiation from directions other than that where the telescope was pointed. Radio astronomers use the term 'stray radiation' to describe this effect. An investigation is conducted to determine the importance of stray radiation for the work of Burstein and Heiles (1978). It is found that the zero offset is well established by radio studies.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.