CO (J = 4→3) and [Ci] Observations of the Carina Molecular Cloud Complex

Abstract

We present large area, fully-sampled maps of the Carina molecular cloud complex in the CO (J = 4 → 3) and neutral carbon [C I] 3 P 1 → 3 P 0 transitions. These data were obtained using the 1.7 meter diameter Antarctic Submillimeter Telescope and Remote Observatory (AST/RO). The maps cover an area of approximately 3 square degrees with a uniform 1 ′ spatial sampling. Analysis of these data, in conjunction with CO (J = 1 → 0) data from the Columbia CO survey and the IRAS HIRES continuum maps for the same region, suggests that the spiral density wave shock associated with the Carina spiral arm may be playing an important role in the formation and dissociation of the cloud complex, as well as in maintaining the internal energy balance of the clouds in this region. Massive stars form at the densest regions of the molecular cloud complex. The winds and outflows associated with these stars have a disrupting effect on the complex and inject mechanical energy into the parent clouds, while the UV radiation from the young stars also heat the parent clouds. The present set of data suggests, however, that massive stars alone may not account for the energetics of the clouds in the Carina region. The details of the data and the correlation among the various data sets hint at the possible role that the spiral density wave shock plays in feeding interstellar turbulence and in heating molecular clouds.

The Bias of Molecular Clump Identification Programs: the Example of the Carina Molecular Clouds

“…The data reveal a much more clumpy and complex structure than other largescale maps of the region made at lower angular resolution (e.g. Zhang et al 2001;Grabelsky et al 1998). A recent large-scale map of 12 CO J = 3 → 2 emission at 20 angular resolution obtained with Atacama Submillimeter Telescope Experiment (ASTE) is shown but not discussed in Yamaguchi (2003).…”

“…The Carina Nebula, at a distance of 2.2 kpc, is part of a giant molecular cloud complex that extends over a projected distance of 130 pc (Grabelsky et al 1988;Fukui et al 1999;Zhang et al 2001). The two most influential star clusters in the nebula are Trumpler 14 and Trumpler 16 (hereafter Tr 14 and Tr 16), which contain a combined total of more than 30 O-type stars (Feinstein 1995).…”

“…Several complexes with a filamentary structure can be identified, extending from the northwest diagonally to the southeast. A large part of this area was covered by an atomic carbon (at 492 GHz) and 12 CO J = 4 → 3 survey from Zhang et al (2001). The integrated 12 CO J = 1 → 0 emission obtained with Mopra defines two major components of the central GMC: the Northern and Southern clouds.…”

Searching for spatial variations ofα2/μin the Milky Way

“…Then, one can assume that, in the outer envelopes of molecular clouds, neutral carbon lies within a thin layer determined by the equilibrium between photoionization/recombination processes on the C + /C 0 side and photodissociation/molecule formation processes on the C 0 /CO side. However, observations (Keene et al 1985;Zhang et al 2001) do not support such a steady-state model, which predicts that C 0 should only arise near the edges of molecular clouds. To explain the observed correlation between the spatial distributions of C 0 and CO, inhomogeneous PDRs with clumping molecular gas were suggested.…”

η Carinae's Dusty Homunculus Nebula from Near-infrared to Submillimeter Wavelengths: Mass, Composition, and Evidence for Fading Opacity

“…We have emphasized that the chemistry of our dust models is consistent with observed abundances in the CNO-processed nebula, supported by analysis of 12 CO and 13 CO lines that indicates a subsolar abundance ratio of CO/H 2 and an enhancement of 13 C. Some caution is needed about the isotopic abundance ratio, however, since chemical fractionation of carbon driven by the reaction 13 C + + CO  12 C + + 13 CO + 34.8 K can occur in dense photodissociation regions (PDRs; Langer et al 1984;Gerin et al 1998; (Mizutani et al 2004) formed at the interface between the HII region and molecular cloud mapped out in CO (Brooks et al 1998;Zhang et al 2001; see also Cox 1995;Smith et al 2000;Brooks et al 2003, for reviews of the large-scale structure of the Carina cloud). Our PACS spectroscopy shows significant emission in the vicinity of the Homunculus, the strongest being in the direct sightline.…”