Star Formation in the Northern Cloud Complex of NGC 2264

We have made continuum and spectral line observations of several outflow sources in the Mon OB1 dark cloud (NGC 2264) using the Heinrich Hertz Telescope (HHT) and ARO 12m millimeter-wave telescope. This study explores the kinematics and outflow energetics of the young stellar systems observed and assesses the impact star formation is having on the surrounding cloud environment. Our data set incorporates 12CO(3-2), 13CO(3-2), and 12CO(1-0) observations of outflows associated with the sources IRAS 06382+1017 and IRAS 06381+1039, known as IRAS 25 and 27, respectively, in the northern cloud complex. Complementary 870 micron continuum maps were made with the HHT 19 channel bolometer array. Our results indicate that there is a weak (approximately less than 0.5%) coupling between outflow kinetic energy and turbulent energy of the cloud. An analysis of the energy balance in the IRAS 25 and 27 cores suggests they are maintaining their dynamical integrity except where outflowing material directly interacts with the core, such as along the outflow axes.Comment: 28 pages including 6 figures, to be published in ApJ 01 July 2006, v645, 1 issu

Exploring Life-Cycles of the ISM at Submillimeter Wavelengths

This thesis focuses on addressing some important aspects of the life cycle of interstellar clouds through observational submillimeter and millimeter-wave studies of star formation and molecular cloud environments and the development of instrumentation to enable these studies.We examine the influence of star formation on parent molecular clouds through a case study of protostellar sources in the Mon OB1 northern cloud complex. An energetics analysis of these star forming regions and associated molecular outflows was carried out, suggesting that the cloud complex maintains its overall integrity, except along outflow axes and that the coupling between outflow kinetic energy and cloud turbulent energy is weak, < ~0.5%. In order to study the larger picture of cloud formation and disruption, this work was expanded to explore the molecular environment at cloud boundaries. To this end, acloud edge survey was undertaken consisting of multi-transition strip scan observations of CO and 13CO toward molecular clouds with a broad range of stellar and star forming characteristics. Our work supports the interpretation that cloud formation is taking place along the southeastern edge of Heiles Cloud 2, and the results will be used as a framework for guiding the analysis of other surveyed cloud edges.Achieving observational capabilities enabling effective studies of life cycles of the ISM is becoming possible through a new generation of heterodyne spectroscopic instruments. Here, we report on characterization measurements of a prototype mixer unit for the 64-pixel SuperCam array, an instrument commissioned to mapover 500 square degrees of the Galactic Plane with very high resolution at 345 GHz. These measurements were crucial to verifying the overall array design and anticipating its performance. Spectroscopic capabilities at THz (< 300 microns) frequencies permits access to a host of diagnostic tools (e.g., high-J CO, CI, NII, & CII) uniquely suited to probe crucial properties of the ISM. The development of heterodynetechnology at these frequencies is largely limited by availability of compact, powerful sources of local oscillator power. We explore the use of waveguide spatial filters in conjunction with Quantum Cascade Lasers, a promising power source at frequenciesabove ~ 2 THz

Deployment of TREND : a low-noise receiver user instrument at 1.25 THz to 1.5 THz for AST/RO at the South Pole

We have developed and constructed a low noise receiver user instrument based on HEB technology. TREND (Terahertz REceiver with NbN HEB Device). The plan was to install TREND on the 1.7 meter diameter AST RO submillimeter wave telescope at the Amundsen/Scott South Pole Station during the austral summer season of 2002/2003. The frequency range of 1.25 THz to 1.5 THz was chosen in order to match the best windows for atmospheric transmission and interstellar spectral lines of special interest. The South Pole Station is the best available site for ground-based THz observations due to the very cold and dry atmosphere over this site. The TREND team is now able to report that this receiver has been installed on schedule and met our goals for its performance. TREND is thus ready to perform astronomical observations in the upcoming austral winter season as soon as the weather becomes suitable for THz work. The first spectral lines which will be observed are the CO J = 11￫10 line at 1.27 THz and the 1.46 THz line of NII. TREND is an NbN Hot Electron Bolometer (HEB) type receiver and the double sideband noise temperature at 1.27 THz has been measured on the telescope to be 1.200 K. The local oscillator is a CO2 laser pumped amplitude stabilized CD30H gas laser. The TREND receiver will pioneer observations from a ground-based telescope at frequencies well above 1 THz. This is also the first time that a receiver can potentially perform an extensive study of the ubiquitous Nil ion, first noted by COBE