A multitransitional CO study of NGC7129

Abstract

New observations of the molecular cloud NGC 7129, in several emission lines of CO, allows an assessment of the effects of recent and ongoing star formation. The CO data is supplemented with limited HCO[superscript +] J = 3 [right arrow] 2 data. The cloud contains a very young star cluster with associated reflection nebulae, surrounded by a sharply-bounded molecular cavity. The CO maps, which are the first high resolution maps covering a significant portion of NGC 7129, reveal much new structure in the molecular ridge, such as gas clumps, and direct evidence for compression of the ridge by the young stars along the eastern border of the cavity. Evidence is presented that supports the idea that triggered star formation has taken place in NGC 7129, and suggests that it is likely to continue.

There is an energetic molecular outflow centred on or near the Be star LkH[alpha] 234, and a bipolar outflow to the south of this star which is associated with a far-infrared source. Additionally, there is high velocity blueshifted gas to the southwest of LkH[alpha] 234 and the molecular cavity. The new [superscript 12]CO J = 3 [right arrow] 2, [superscript 13]CO J = 3 [right arrow] 2, and [superscript 12]CO J = 2 [right arrow] 1 data permit a re-evaluation of the energetics and structure of the high velocity gas in the region. Optical depths, excitation temperatures, and column densities are calculated for each velocity channel at all positions in the redshifted outflow associated with LkH[alpha] 234. (Abstract shortened by UMI.)