Spatially resolved images of reactive ions in the Orion Bar^,★★.

ABSTRACT: We report high angular resolution (4.9″×3.0″) images of reactive ions SH⁺, HOC⁺, and SO⁺ toward the Orion Bar photodissociation region (PDR). We used ALMA-ACA to map several rotational lines at 0.8 mm, complemented with multi-line observations obtained with the IRAM 30 m telescope. The SH⁺ and HOC⁺ emission is restricted to a narrow layer of 2″- to 10″-width (≈800 to 4000 AU depending on the assumed PDR geometry) that follows the vibrationally excited [Formula: see text] emission. Both ions efficiently form very close to the H/H₂ transition zone, at a depth of A_v≲1 mag into the neutral cloud, where abundant C⁺, S⁺, and [Formula: see text] coexist. SO⁺ peaks slightly deeper i

SUBMITTER: Goicoechea JR 

PROVIDER: S-EPMC5500010 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature