High-resolution CARMA Observation of Molecular Gas in the North America and Pelican Nebulae

TL;DR

This study uses high-resolution CARMA observations combined with single-dish data to analyze the molecular gas structure and star formation activity in the North America and Pelican Nebulae, highlighting feedback effects from a central O star.

Contribution

First high-resolution molecular line survey of NAP Nebulae combining CARMA and single-dish data, revealing detailed gas dynamics and feedback effects.

Findings

Molecular gas shaped by the W80 HII bubble driven by an O star

Identification of remnant molecular clouds heated and stripped by the star

Detection of star formation activity in some regions despite feedback effects

Abstract

We present the first results from a CARMA high-resolution $^{12}$CO(1-0), $^{13}$CO(1-0), and C$^{18}$O(1-0) molecular line survey of the North America and Pelican (NAP) Nebulae. CARMA observations have been combined with single-dish data from the Purple Mountain 13.7m telescope to add short spacings and produce high-dynamic-range images. We find that the molecular gas is predominantly shaped by the W80 HII bubble that is driven by an O star. Several bright rims are probably remnant molecular clouds heated and stripped by the massive star. Matching these rims in molecular lines and optical images, we construct a model of the three-dimensional structure of the NAP complex. Two groups of molecular clumps/filaments are on the near side of the bubble, one being pushed toward us, whereas the other is moving toward the bubble. Another group is on the far side of the bubble and moving away. The young stellar objects in the Gulf region reside in three different clusters, each hosted by a cloud from one of the three molecular clump groups. Although all gas content in the NAP is impacted by feedback from the central O star, some regions show no signs of star formation, while other areas clearly exhibit star formation activity. Other molecular gas being carved by feedback includes the cometary structures in the Pelican Head region and the boomerang features at the boundary of the Gulf region. The results show that the NAP complex is an ideal place for the study of feedback effects on star formation.