Inaug.-diss.--Bonn. / Vita.

Inaug.-diss.--Bonn. / Vita.

Herschel and JCMT surveys of nearby star-forming regions have provided excellent images of cold dust emission across several wavelengths with unprecedented dynamic range and resolutions. Here we present spectral emissivity index and temperature maps of dust in the star-forming clumps of the Perseus molecular cloud determined from fitting SEDs to the combined Herschel and JCMT observations in the 160 μm, 250 μm, 350 μm, 500 μm, and 850 μm bands, employing the technique developed by Sadavoy et al. (2013). In NGC1333, the most complex and active star-forming clump in Perseus, we demonstrate that CO line contamination in the JCMT SCUBA-2 850 μm band is typically insignificant. The derived spectral emissivity index, β, and dust temperature, T, ranges between 0.8 - 3.0 and 7 - 50 K, respectively. Throughout Perseus, we see indications of heating from B stars and embedded protostars, and smooth β variations on the smaller scales. The distribution of β values seen in each clump differs from one clump to another, and is in general different from the diffuse ISM values (i.e., ~2), suggesting that dust grain evolution is significant in star-forming clumps. We also found coincidences between low β regions and local temperature peaks as well as locations of outflows, which may provide hints to the origins of these low β value grains, and dust grain evolution in star-forming clumps in general. / Graduate / mcychen@uvic.ca

This dissertation presents new Herschel observations at 70 micron, 160 micron, 250 micron, 350 micron, and 500 micron of the Perseus molecular cloud from the Herschel Gould Belt Survey. The Perseus molecular cloud is a nearby star-forming region consisting of seven main star-forming clumps. The Herschel observations are used to characterize and contrast the properties of these clumps, and to study their embedded core populations. First, we probed the exceptionally young clump, B1-E. Using complementary molecular line data, we demonstrate that B1-E is likely fragmenting into a first generation of dense cores in relative isolation. Such a core formation region has never been observed before. Second, we use complementary long wavelength observations at 850 micron to study the dust properties in the larger, more active B1 clump. We find that Herschel data alone cannot constrain well the dust properties of cold dust emission and that long wavelength observations are needed. Additionally, we find evidence of dust grain growth towards the dense cores in B1, where the dust emissivity index, beta, varies from the often assumed value of beta = 2. In the absence of long wavelength observations, however, assuming beta = 2 is preferable over measuring beta with the Herschel-only bands. Finally, we use the source extraction code, getsources, to identify the core populations within each clump from the Herschel data. In addition, we use complementary archival infrared observations to study their populations of young stellar objects (YSOs). We find that the more massive clumps have an excess of older stage YSOs, suggesting that these regions contracted first. Starless cores are typically associated with peaks in the column density, where those found towards regions of higher column density also have higher average densities and colder temperatures. Starless cores associated with a strong, local interstellar radiation field, however, have higher temperatures. We find that the clumps with the most prominent high column density tails also had the highest fractions of early-stage YSOs. This relation suggests that the quantity of high column density material corresponds to recent star formation activity. / Graduate / 0606

Star formation is a complex hierarchical process that witnesses the transfer of mass among a range of scales from large diffuse molecular clouds to crowded clumps and finally down to prestellar cores. The final stage of this process has prestellar cores actively accreting matter while undergoing gravitational collapse on their way to becoming main sequence stars. This thesis presents multi wavelength submillimeter observations of the Perseus molecular cloud using 160 μm, 250 μm, 350 μm, and 500 μm maps of thermal dust emission from the Herschel space observatory. Additionally C18O J = 3 → 2 spectral line emission is observed in four star forming clumps within Perseus using the James Clerk Maxwell Telescope. Spectral line emission allows for the separation of material along the line of sight. Prestellar core mass is derived from observational maps using various source finding algorithms. The mass is overestimated when compared to prestellar core mass found from spectral line data. This overestimation can be mitigated with careful selection of source finding algorithm and background removal. Further, the prestellar core mass derived from spectral line data was the closest match to the initial stellar mass function over dust maps. However, both the spectral line masses and dust map masses do not agree with the IMF confirming a star forming efficiency factor in the evolutionary step between prestellar core and main sequence star. Lastly, a filamentary analysis finds that high mass stars preferentially form in crowded regions close to, or contained within, filament structure. / Thesis / Master of Science (MSc) / Star formation is a complex hierarchical process that witnesses the transfer of mass among a range of scales from large diffuse molecular clouds to crowded clumps and finally down to prestellar cores. The final stage of this process has prestellar cores actively accreting matter while undergoing gravitational collapse on their way to becoming main sequence stars. This thesis presents multi wavelength submillimeter observations of the Perseus molecular cloud using 160 μm, 250 μm, 350 μm, and 500 μm maps of thermal dust emission from the Herschel space observatory. Additionally carbon monoxide spectral line emission is observed in four star forming clumps within Perseus using the James Clerk Maxwell Telescope. Spectral line emission allows for the separation of material along the line of sight. Prestellar core mass is derived from observational maps using various source finding algorithms. The mass is overestimated when compared to prestellar core mass found from spectral line data. This overestimation can be mitigated with careful selection of source finding algorithm and background removal. Further, the prestellar core mass derived from spectral line data was the closest match to the initial stellar mass function over dust maps. However, both the spectral line masses and dust map masses do not agree with the IMF confirming a star forming efficiency factor in the evolutionary step between prestellar core and main sequence star. Lastly, a filamentary analysis finds that high mass stars preferentially form in crowded regions close to, or contained within, filament structure.

No description available.

This thesis deals with the design and implementation of application for control of mobile robot. In the introductory section is discussed used platform GEARS-SMP, the principle of functionality of protocol for servo motors control, format M-JPEG and standard H.264. Further work is dedicated to analysis of designing user interface in robotic applications, available options for control devices and hardware used in remote controller. The following part focuses on the design of robotic application, especially on graphic user interface and virtual head-up display and follow-up implementation of created application in Raspberry Pi. In the end, thesis describes implemented software solution and compares resulting application with the created design.