Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: Christine D. Wilson. Includes bibliographical references. Also available online.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 148-155).

Dissertation : Sciences : Chicago : 1913. / Astrophysical journal, Vol. XXXVIII, no. 3.

Thesis (M.S.)--University of Toledo, 2009. / Typescript. "Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Science in Physics." "A thesis entitled"--at head of title. Bibliography: leaves 70-71.

Thesis (doctoral)--Friedrich-Wilhelms-Universität zu Berlin, 1885. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis--Harvard University. / Includes bibliographical references (leaves 192-196).

The properties of astrophysical masers are governed by the physical conditions of circumstellar envelopes of evolved stars, implying a connection between maser and mass-loss phenomena. Although similar studies to another type of mass-losing star, Asymptotic Giant Branch (AGB) stars, have been conducted, a quantitative understanding for the case of Red Supergiants (RSGs) is still largely lacking. Recently, more and more galactic massive clusters are discovered and studied, which provide a coeval environment to investigate the evolution of cool massive evolved stars with similar distance and metallicity. Among them, Westerlund 1 (Wd1) is one of the most massive open clusters, classified as Super Star Clusters (SSCs), within the Milky Way harboring 4 RSGs. We have 2 goals in this project. We aim to investigate the relationship between SiO maser detection and mass-loss behavior of RSGs in massive clusters, in order to explore the possibility of developing SiO maser as an evolutionary indicator of RSGs. We also aim to determine the kinematic properties of Wd1 with the aid of SiO maser. We report on observation of 43 GHz SiO (v = 1, J = 1–0) maser towards Wd1 conducted with Australia Telescope Compact Array (ATCA). We also make use of archival 22 GHz H2O maser (616–523) in help of studying kinematic of Wd1. We derive the maser detection information and stellar velocities from maser data. We also compile an extra sample of 36 RSGs, which surveyed in SiO maser before, within massive clusters, e.g. Red Supergiant Cluster 1 (RSGC1), Red Supergiant Cluster 2 (RSGC2), Perseus OB association 1 (Per OB 1) and Mercer et al.’s #8 (Mc8), and organize their photometric data from 2MASS, GLIMPSE, MSX, AKARI and WISE to derive their spectral energy distributions (SEDs). Luminosity, effective temperature and mass-loss rate are derived from fitting the SEDs with DUSTY model in order to search for correlations between mass-loss rate, SiO maser properties and evolution of RSGs. We detected SiO maser emission towards 2 RSGs (W 237 and W 26) in Wd1. These 2 RSGs also emit H2O maser as revealed from archival H2O maser observation data. We noticed that SiO masers tend to be detected towards RSGs with higher luminosity and mass-loss rate. We also determined the kinematic distance of Wd1 to be 3.3 kpc. From that result, we conclude that SiO maser is an effective evolution indicator for RSGs, which traces RSGs with high massloss rate. We also show that the age of RSGs in Wd1 is 10 ± 2 Myr which support the multi-generation star formation scenario in Wd1. / published_or_final_version / Physics / Master / Master of Philosophy

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