The Complete Nature of the Warm Dust Shell in Perseus

The Perseus molecular cloud complex is ak30 pc long chain of molecular clouds most well known for the two star-forming clusters NGC 1333 and IC 348 and the well-studied outflow source in B5. However, when studied at midto far-infrared wavelengths, the region is dominated by a 10 pc diameter shell of warm dust, likely generated by an H ii region caused by the early-B star HD 278942. Using a revised calibration technique the COMPLETE team has produced high-sensitivity temperature and column density maps of the Perseus region from IRAS Sky Survey Atlas (ISSA) 60 and 100 m data. In this paper, we combine the ISSA-based dust-emission maps with other observations collected as part of the COMPLETE Survey, alongwith archival H andMSX observations.Molecular line observations from FCRAO and extinction maps constructed by applying the NICER method to the 2MASS catalog provide independent estimates of the ‘‘true’’ column density of the shell. H emission in the region of the shell confirms that it is most likely an H ii region located behind the cloud complex, and 8 m data fromMSX indicate that the shell may be interacting with the cloud. Finally, the two polarization components seen toward background stars in the region by Goodman et al. can be explained by the association of the stronger component with the shell. If confirmed, this would be the first observation of a parsec-scale swept-up magnetic field. Subject headinggs: dust, extinction — H ii regions — infrared: ISM — ISM: individual (G159.6-18.5) — radio lines: ISM Online material: color figure