RUI: The Circumgalactic Medium in the Local Universe

Providence College, Providence RI

Investigators

Abstract

Astronomers seek to understand how stars and galaxies formed. Galaxies have come to exist in relation to the diffuse gas that surrounds them. Understanding this relationship is essential for understanding how galaxies, including our own galaxy (the Milky Way), evolved into their present forms. Ribaudo and colleagues will combine observations of nearby galaxies and their surrounding gas made with the Arecibo Observatory with other ground-based observations as well Hubble Space Telescope archival data. These combined observations probe the constituents of the gas surrounding galaxies and its physical distribution. Such information reveals the inter-relationship between this gas and the galaxies within. This project will provide educational research opportunities for three undergraduate students at Utica College and laboratory activities for undergraduate education. This project will also include outreach to the Utica Children?s Museum, where the PI has previously been involved. Such outreach activities may include creating ?dirty snowballs? to illustrate comet formation and hands-on spectroscopy and observing programs. Ribaudo and collaborators will use results of the Arecibo Legacy Fast ALFA (ALFALFA) Survey to generate a sample of galaxies for study. Their physical properties are determined in conjunction with data from the Sloan Digital Sky Survey (SDSS). The CircumGalactic Medium (CGM) is investigated using absorption spectroscopy of background quasars from archival Hubble Space Telescope Cosmic Origins Spectrograph data. They will characterize the CGM using absorption line diagnostics including Lyman-alpha, CII, SiII, SiIII, NV and OVI. They will investigate covering fractions, equivalent widths of spectral lines and metallicities. These researchers will characterize the properties of the CGM of galaxies in the nearby universe and compare them to previous studies at z > 0.1 and smaller studies of more nearby galaxies. Results of this work will be presented by undergraduates at regional (New York area) and national (AAS) astronomy conferences in addition to being published in refereed journals.