Dark matter in dwarf irregular galaxies, DDO 210 and DDO 169

It has been proposed that dwarf irregular galaxies can be separated into two classes based on their formation mechanism; that they are the result of the collapse of a primordial gas cloud or that they are the product of condensation of gas in the tidal tails of interacting galaxies. Simulations of galaxy interactions indicate that one can differentiate between these two scenarios by the dark matter content, with a low dark matter content indicating a fossil tidal dwarf. The purpose of this dissertation was to explore the dark matter distribution of two dwarf irregular galaxies using optical and neutral atomic hydrogen data. For DDO 210, the method of mass-modelling was used to determine its dark matter. About 64% of the galaxy mass was calculated to be in the form of dark matter and hence it is unlikely to be a fossil tidal dwarf. The method of mass-modelling could not be used for DDO 169 as the galaxy shows evidence of being tidally disrupted and hence, has a disturbed velocity field. Instead, the suggestion that dark matter might be responsible for a pressure anomaly in DDO 169 was tested to determine its dark matter content. According to this method, a pressure anomaly does exist but without a concrete value for the scale-height, it is unclear whether the anomaly is due to the presence of dark matter. Hence one cannot say how much dark matter might actually be present in DDO 169. A rotation curve would be required to do this. ^

The H I chronicles of LITTLE THINGS blue compact dwarf galaxies

Star formation occurs when the gas (mostly atomic hydrogen; H I) in a galaxy becomes disturbed, forming regions of high density gas, which then collapses to form stars. In dwarf galaxies it is still uncertain which processes contribute to star formation and how much they contribute to star formation. Blue compact dwarf (BCD) galaxies are low mass, low shear, gas rich galaxies that have high star formation rates when compared to other dwarf galaxies. What triggers the dense burst of star formation in BCDs but not other dwarfs is not well understood. It is often suggested that BCDs may have their starburst triggered by gravitational interactions with other galaxies, dwarf-dwarf galaxy mergers, or consumption of intergalactic gas. However, there are BCDs that appear isolated with respect to other galaxies, making an external disturbance unlikely.^ Here, I study six apparently isolated BCDs from the LITTLE THINGS sample in an attempt to understand what has triggered their burst of star formation. LITTLE THINGS is an H I survey of 41 dwarf galaxies. Each galaxy has high angular and velocity resolution H I data from the Very Large Array (VLA) telescope and ancillary stellar data. I use these data to study the detailed morphology and kinematics of each galaxy, looking for signatures of starburst triggers. In addition to the VLA data, I have collected Green Bank Telescope data for the six BCDs. These high sensitivity, low resolution data are used to search the surrounding area of each galaxy for extended emission and possible nearby companion galaxies.^ The VLA data show evidence that each BCD has likely experienced some form of external disturbance despite their apparent isolation. These external disturbances potentially seen in the sample include: ongoing/advanced dwarf-dwarf mergers, an interaction with an unknown external object, and external gas consumption. The GBT data result in no nearby, separate H I companions at the sensitivity of the data. These data therefore suggest that even though these BCDs appear isolated, they have not been evolving in isolation. It is possible that these external disturbances may have triggered the starbursts that defines them as BCDs.^

The democratization of higher education in Jamaica: The role of the University of the West Indies

The University of the West Indies (UWI), established in the British colony of Jamaica in 1948, was mandated to serve the “brightest and the best” of the British colonies. Unfortunately, the austerity of Jamaica's economy has not helped to augment an “open door” access to higher education, and UWI is often criticized for not implementing policies to sustain the democratization of higher education; it is accused of functioning as an elitist institution. ^ The purpose of this qualitative study was to determine whether UWI functions democratically as an institution to influence the equity of higher education in Jamaica. A review of the literature reveals many interpretations of the democratization of higher education. Three of Spaulding and Kargodorian's four criteria were utilized to analyze this research. They were (1) equality of access to higher education, (2) equality of participation within the institution of higher education, and (3) equality of educational results. Multiple sources of written data augmented by interviews in Jamaica and Miami were utilized. ^ The analysis revealed that UWI functions in a collaborative relationship with Jamaica's Centralized Educational System as well as with the country's political, economic, and social realms to impact the democratization of higher education. Documentation suggests that, although strong traditional influences continue to exist, UWI has deviated from its original mandate and instead, flexible admittance policies and diversification of expanded programs have contributed to greater accessibility. ^ Despite UWI's reports of improvements which have contributed to more access, UNESCO and some interviewees have not been impressed. A World Bank report on enrollment ratio at the university level in English speaking Caribbean countries reflects less than one percent of the age cohort. The Jamaicans interviewed, especially those from the lower class, felt that their democratic right to receive higher education was not met. UNESCO regards UWI's efforts as just putting a “dent” in the problem. ^ Recommendations include continuing efforts towards developing curricula more relevant to the Jamaican society, increasing distance education in order to ease UWI's load, expanding financial partnerships with private sectors, and extending research in collaboration with large local and foreign private companies. ^