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In this paper, we present the first results from a CARMA high-resolution (CO)-C-12(1-0), (CO)-C-13(1-0), and (CO)-O-18(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 13.7 m telescope, to add short spacings and to produce high-dynamic-range images. We find that the molecular gas is predominantly shaped by the W80 H ii bubble, driven by an O star. Several bright rims noted in the observation 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 is 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. Additional molecular gas being carved by feedback includes 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.

In this paper, we present the first results from a CARMA high-resolution (CO)-C-12(1-0), (CO)-C-13(1-0), and (CO)-O-18(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 13.7 m telescope, to add short spacings and to produce high-dynamic-range images. We find that the molecular gas is predominantly shaped by the W80 H ii bubble, driven by an O star. Several bright rims noted in the observation 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 is 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. Additional molecular gas being carved by feedback includes 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.

We have investigated the formation and kinematics of submillimeter (submm) continuum cores in the Orion A molecular cloud. A comparison between submm continuum and near-infrared extinction shows a continuum core detection threshold of A(v) similar to 5-10 mag. The threshold is similar to the star formation extinction threshold of A(v) similar to 7 mag proposed by recent work, suggesting a universal star formation extinction threshold among clouds within 500 pc to the Sun. A comparison between the Orion A cloud and a massive infrared dark cloud G28.37 +0.07 indicates that Orion A produces more dense gas within the extinction range 15 mag less than or similar to A(v) less than or similar to 60 mag. Using data from the CARMA-NRO Orion Survey, we find that dense cores in the integral-shaped filament (ISF) show subsonic core-to-envelope velocity dispersion that is significantly less than the local envelope line dispersion, similar to what has been found in nearby clouds. Dynamical analysis indicates that the cores are bound to the ISF. An oscillatory core-to-envelope motion is detected along the ISF. Its origin is to be further explored.

We have investigated the formation and kinematics of submillimeter (submm) continuum cores in the Orion A molecular cloud. A comparison between submm continuum and near-infrared extinction shows a continuum core detection threshold of A(v) similar to 5-10 mag. The threshold is similar to the star formation extinction threshold of A(v) similar to 7 mag proposed by recent work, suggesting a universal star formation extinction threshold among clouds within 500 pc to the Sun. A comparison between the Orion A cloud and a massive infrared dark cloud G28.37 +0.07 indicates that Orion A produces more dense gas within the extinction range 15 mag less than or similar to A(v) less than or similar to 60 mag. Using data from the CARMA-NRO Orion Survey, we find that dense cores in the integral-shaped filament (ISF) show subsonic core-to-envelope velocity dispersion that is significantly less than the local envelope line dispersion, similar to what has been found in nearby clouds. Dynamical analysis indicates that the cores are bound to the ISF. An oscillatory core-to-envelope motion is detected along the ISF. Its origin is to be further explored.

We present the first results from a new, high-resolution (CO)-C-12(1-0), (CO)-C-13(1-0), and (CO)-O-18(1-0) molecular-line survey of the Orion A cloud, hereafter referred to as the CARMA-NRO Orion Survey. CARMA observations have been combined with single-dish data from the Nobeyama 45 m telescope to provide extended images at about 0.01 pc resolution, with a dynamic range of approximately 1200 in spatial scale. Here we describe the practical details of the data combination in uv space, including flux scale matching, the conversion of single-dish data to visibilities, and joint deconvolution of single-dish and interferometric data. A Delta-variance analysis indicates that no artifacts are caused by combining data from the two instruments. Initial analysis of the data cubes, including moment maps, average spectra, channel maps, position-velocity diagrams, excitation temperature, column density, and line ratio maps, provides evidence of complex and interesting structures such as filaments, bipolar outflows, shells, bubbles, and photo-eroded pillars. The implications for star formation processes are profound, and follow-up scientific studies by the CARMA-NRO Orion team are now underway.

We present the first results from a new, high-resolution (CO)-C-12(1-0), (CO)-C-13(1-0), and (CO)-O-18(1-0) molecular-line survey of the Orion A cloud, hereafter referred to as the CARMA-NRO Orion Survey. CARMA observations have been combined with single-dish data from the Nobeyama 45 m telescope to provide extended images at about 0.01 pc resolution, with a dynamic range of approximately 1200 in spatial scale. Here we describe the practical details of the data combination in uv space, including flux scale matching, the conversion of single-dish data to visibilities, and joint deconvolution of single-dish and interferometric data. A Delta-variance analysis indicates that no artifacts are caused by combining data from the two instruments. Initial analysis of the data cubes, including moment maps, average spectra, channel maps, position-velocity diagrams, excitation temperature, column density, and line ratio maps, provides evidence of complex and interesting structures such as filaments, bipolar outflows, shells, bubbles, and photo-eroded pillars. The implications for star formation processes are profound, and follow-up scientific studies by the CARMA-NRO Orion team are now underway.