The Multiphase Intergalactic Medium towards PKS 2155-304

We study the cluster of H I and O VI absorption systems and the claimed detection of O VIII absorption from the intergalactic medium at z ~ 0.0567, associated with a group of galaxies toward the BL Lac object PKS 2155-304. As measured by spectrographs on the Hubble Space Telescope, Far Ultraviolet Spectroscopic Explorer, and Chandra, this system appears to contain gas at a variety of temperatures. We analyze this multi-phase gas in a clumpy-infall model. From the absence of C IV and Si III absorption in the Ly-alpha clouds, we infer metallicities less than 2.5-10% of solar values. The only metals are detected in two O VI absorption components, offset by +/- 400 km/s from the group barycenter (cz ~ 16,600 km/s). The O VI components may signify "nearside" and "backside" infall into the group potential well, which coincides with the claimed O VIII absorption. If the claimed O VIII detection is real, our analysis suggests that clusters of strong Ly-alpha and O VI absorbers, associated with groups of galaxies, may be the "signposts" of shock-heated, metal-enriched baryons. Through combined UV and X-ray spectra of H I and O VI, O VII, and O VIII, one may be able to clarify the heating mechanism of this multiphase gas.Comment: Accepted for ApJL (2003), 11 pages, 1 color figur

A study of some cyclohexyl tin compounds

Although a large number of organotin compounds have been prepared (Dr. Garzuly lists over one hundred and fifty), comparatively little is known about them. It was the purpose of this investigation to study some of the cyclohexyl tin compounds with a view toward finding out more about their preparation and properties, and to prepare some that had not been prepared before. Unfortunately time and circumstances prevented the latter

The Traumatized/traumatizing Subject In Anna Deavere Smith, Suzan-Lori Parks, And August Wilson

The Traumatized/Traumatizing Subject in Anna Deavere Smith, Suzan-Lori Parks, and August Wilson explores how drama, as a genre, is particularly suited for capturing aspects of trauma in ways that other genres cannot; this argument reinforces that trauma must be studied within the humanities, specifically within literature programs. Recognizing that trauma in and of itself is tied to issues of narrativization, textuality, and performativity, this project notes that Smith\u27s, Parks\u27s, and Wilson\u27s work collectively attempt to traumatize contemporary viewing audiences and make them aware—cognitively and emotionally—of the hardships of discrimination and racism, which themselves can be seen as examples of generational trauma, trauma linked to diaspora, and trauma arising from long-term, cumulative, and collective suffering. Smith\u27s, Parks\u27s, and Wilson\u27s works are no longer about catharsis, but empathic unsettlement and making audience members realize the ways in which individuals, particularly those who consider themselves to be bystanders, operate, in the parlance of Judith Lewis Herman, as both victim and perpetrator. These particular authors show how trauma can be conveyed to audiences not only through plot lines, but through various stylistic and aesthetic devices, and as such, their dramas explore the ways in which trauma is manifested and communicated to audiences, while also challenging commonly held ideas about trauma. Smith\u27s monodramas Fires in the Mirror and Twilight, both of which focus on late twentieth-century civil disturbances, provide commentary on the conditions that must be in place for communal healing to occur. Parks\u27s Topdog/Underdog, Venus, and The America Play focus on individuals who succumb to the traumas they are psychically forced to relive. In contrast, Wilson\u27s Gem of the Ocean, the first work in his century cycle, offers an instance of healing, challenging popular ideas about this process by emphasizing its physicality and the degree to which choice impacts that process. All three playwrights emphasize the communality of trauma and the ways in which it is socially determined and negotiated; they accomplish this by actively engaging audiences through a destabilization of the fourth wall, embedded performances, and a stylistic and thematic focus on dissociation, fragmentation, liminality, and simultaneity

Enrolment Demand versus Accessibility at Canada's Universities

An increasing number of young Canadians want the benefits of a university education, placing huge demands on Canada's universities. Our universities have responded to this demand by increasing enrolment significantly over the past several years, but per-student funding levels have not kept pace. This enrolment growth is unsustainable without increased government support to boost institutional capacity and hence accessibility. Without additional funds, either access or educational quality—or both—will suffer.Un nombre croissant de jeunes Canadiens désire profiter des avantages que procure une éducation universitaire, ce qui met de la pression sur les universités canadiennes. Nos universités ont donc accepté davantage d'inscriptions au cours des dernières années mais le financement par étudiant n'a pas suivi le même rythme. Il ne sera donc pas possible de maintenir cette croissance sans un soutien accru du gouvernement pour stimuler la capacité institutionnelle et son accessibilité. Sans un financement additionnel, l'accès à l'enseignement ou la qualité de l'enseignement—ou même les deux—seront touchés

Highly Ionized High-Velocity Clouds toward PKS 2155-304 and Markarian 509

To gain insight into four highly ionized high-velocity clouds (HVCs) discovered by Sembach et al. (1999), we have analyzed data from the Hubble Space Telescope (HST) and Far Ultraviolet Spectroscopic Explorer (FUSE) for the PKS 2155-304 and Mrk 509 sight lines. We measure strong absorption in OVI and column densities of multiple ionization stages of silicon (SiII/III/IV) and carbon (CII/III/IV). We interpret this ionization pattern as a multiphase medium that contains both collisionally ionized and photoionized gas. Toward PKS 2155-304, for HVCs at -140 and -270 km/s, respectively, we measure logN(OVI)=13.80+/-0.03 and log N(OVI)=13.56+/-0.06; from Lyman series absorption, we find log N(HI)=16.37^(+0.22)_(-0.14) and 15.23^(+0.38)_(-0.22). The presence of high-velocity OVI spread over a broad (100 km/s) profile, together with large amounts of low-ionization species, is difficult to reconcile with the low densities, n=5x10^(-6) cm^(-3), in the collisional/photoionization models of Nicastro et al. (2002), although the HVCs show a similar relation in N(SiIV)/N(CIV) versus N(CII)/N(CIV) as high-z intergalactic clouds. Our results suggest that the high-velocity OVI in these absorbers do not necessarily trace the WHIM, but instead may trace HVCs with low total hydrogen column density. We propose that the broad high-velocity OVI absorption arises from shock ionization, at bowshock interfaces produced from infalling clumps of gas with velocity shear. The similar ratios of high ions for HVC Complex C and these highly ionized HVCs suggest a common production mechanism in the Galactic halo.Comment: 38 pages, including 10 figures. ApJ, 10 April, 2004. Replaced with accepted versio

Unravelling the Mysteries of the Leo Ring: An Absorption Line Study of an Unusual Gas Cloud

Since the 1980's discovery of the large (2x10^9 Msun) intergalactic cloud known as the Leo Ring, this object has been the center of a lively debate about its origin. Determining the origin of this object is still important as we develop a deeper understanding of the accretion and feedback processes that shape galaxy evolution. We present HST/COS observations of three sightlines near the Ring, two of which penetrate the high column density neutral hydrogen gas visible in 21 cm observations of the object. These observations provide the first direct measurement of the metallicity of the gas in the Ring, an important clue to its origins. Our best estimate of the metallicity of the ring is ~10% Zsun, higher than expected for primordial gas but lower than expected from an interaction. We discuss possible modifications to the interaction and primordial gas scenarios that would be consistent with this metallicity measurement.Comment: 11 pages, 7 figures, accepted Ap