Simulating Star Formation and Feedback in Galactic Disk Models

We use a high-resolution grid-based hydrodynamics method to simulate the multi-phase interstellar medium in a Milky Way-size quiescent disk galaxy. The models are global and three-dimensional, and include a treatment of star formation and feedback. We examine the formation of gravitational instabilities and show that a form of the Toomre instability criterion can successfully predict where star formation will occur. Two common prescriptions for star formation are investigated. The first is based on cosmological simulations and has a relatively low threshold for star formation, but also enforces a comparatively low efficiency. The second only permits star formation above a number density of 1000 cm^-3 but adopts a high efficiency. We show that both methods can reproduce the observed slope of the relationship between star formation and gas surface density (although at too high a rate for our adopted parameters). A run which includes feedback from type II supernovae is successful at driving gas out of the plane, most of which falls back onto the disk. This feedback also substantially reduces the star formation rate. Finally, we examine the density and pressure distribution of the ISM, and show that there is a rough pressure equilibrium in the disk, but with a wide range of pressures at a given location (and even wider for the case including feedbackComment: 14 pages, 12 figures, accepted to Astrophysical Journa

An Interview with Terry Wragg on the Work of the Leeds Animation Workshop

Based in the city of Leeds in the north of England, Leeds Animation Workshop describes itself as a “not-for-profit, cooperative company, which produces and distributes animated films and films on social and educational issues.” The organization was formally established in 1978 following a collaboration by a group of women on the film Who Needs Nurseries? We Do! In this interview Terry Wragg, a member of the group since that founding period, talks with Yvonne Tasker about funding patterns, filmmaking, the women's movement, and the significance of the workshop movement in the United Kingdom

Women, sf spectacle and the mise-en-scene of adventure in the Star Wars franchise

This article explores the gendered work of the Star Wars franchise within the generic frame of sf. In the context of this special issue around women in space, I explore here the mise-en-scène of adventure in the Star Wars franchise, focusing on The Force Awakens (2015) and Rogue One (2016). Space and the juxtaposition of planets with spacecraft provides one of the series’ recurrent establishing shots, indicating points of arrival and departure; along with the representation of light speed through a vanishing point, such shots serve to signal distance in both spatial and temporal terms. Although narrative and thematic elements are important aspects of the argument presented here, the article elaborates the centrality of setting and landscape in the twenty-first-century films, notably the construction of multiple worlds as sets for melodramatic action. Female heroism is staged in the films I explore here in a cinematic space of visual effects and spectacle across diverse settings including desert and forest landscapes, mechanised interiors and, of course, space itself. I argue that these spectacular settings are important both visually and thematically, elaborating key themes of freedom, loss and redemption in and through the ground, the environment and space

Sensation/investigation: crime television and the action aesthetic

This article explores the interface between crime television and action television, arguing that action/crime is a significant mode which has typically been overlooked in studies of the genre. It engages with the history of action/crime and its most prominent formal features, discussing in more detail NCIS (2003–present) and The Blacklist (2013–present), and foregrounding the sensational elements of violence and physical movement through space as well as the flows of data and dynamic rendering of analysis typical of forensic crime television. Action/crime is framed as one of several modes which can be seen to organise and inflect crime content; in this way the piece suggests that textual approaches are most productive when premised on an understanding of the fluid, modal aspects of television genre

Vernacular Feminism: Gendered Media Cultures and Historical Perspectives on Postdiscourse

Although media studies as a discipline has long been involved in various theoretical elaborations of the “post,” it has been concerned far less often with the past that is purportedly posted. In this piece, the concept of postfeminism provides a useful case to highlight how thoughtful engagement with the past has immense value for contemporary media scholarship. I suggest that postfeminist scholarship has typically tackled history only obliquely—via generational tropes—and that a more direct engagement with media history allows an understanding that reaches past the “now” with which postdiscourse tends to concern itself. Patterns of continuity and change have been brought into view through the access to historical media formats facilitated by digital archives. I propose a concept of vernacular feminism as a tool for analyzing historical postfeminism, pointing to the broader relevance for postdiscourses that involve an evocation of the past in the present

Dense Cloud Formation and Star Formation in a Barred Galaxy

We investigate the properties of massive, dense clouds formed in a barred galaxy and their possible relation to star formation, performing a two-dimensional hydrodynamical simulation with the gravitational potential obtained from the 2Mass data from the barred spiral galaxy, M83. Since the environment for cloud formation and evolution in the bar region is expected to be different from that in the spiral arm region, barred galaxies are a good target to study the environmental effects on cloud formation and the subsequent star formation. Our simulation uses for an initial 80 Myr an isothermal flow of non-self gravitating gas in the barred potential, then including radiative cooling, heating and self-gravitation of the gas for the next 40 Myr, during which dense clumps are formed. We identify many cold, dense gas clumps for which the mass is more than $10^4M_{\odot}$ (a value corresponding to the molecular clouds) and study the physical properties of these clumps. The relation of the velocity dispersion of the identified clump's internal motion with the clump size is similar to that observed in the molecular clouds of our Galaxy. We find that the virial parameters for clumps in the bar region are larger than that in the spiral arm region. From our numerical results, we estimate star formation in the bar and spiral arm regions by applying the simple model of Krumholtz and McKee (2005). The mean relation between star formation rate and gas surface density agrees well with the observed Kennicutt-Schmidt relation. The SFE in the bar region is $\sim 60$ of the spiral arm region. This trend is consistent with observations of barred galaxies.Comment: 9 pages, 16 figures. Accepted for publication in the MNRA

Follow-up monitoring in a cat with leishmaniosis and coinfections with Hepatozoon felis and ‘Candidatus Mycoplasma haemominutum’

Case summary A 6-year-old female neutered domestic shorthair cat from Cyprus was presented with multiple ulcerated skin nodules. Cytology and histopathology of the lesions revealed granulomatous dermatitis with intracytoplasmic organisms, consistent with amastigotes of Leishmania species. Biochemistry identified a mild hyperproteinaemia. Blood extraction and PCR detected Leishmania species, Hepatozoon species and ‘Candidatus Mycoplasma haemominutum’ (CMhm) DNA. Subsequent sequencing identified Hepatozoon felis. Additionally, the rRNA internal transcribed spacer 1 locus of Leishmania infantum was partially sequenced and phylogeny showed it to cluster with species derived from dogs in Italy and Uzbekistan, and a human in France. Allopurinol treatment was administered for 6 months. Clinical signs resolved in the second month of treatment with no deterioration 8 months post-treatment cessation. Quantitative PCR and ELISA were used to monitor L infantum blood DNA and antibody levels. The cat had high L infantum DNA levels pretreatment that gradually declined during treatment but increased 8 months post-treatment cessation. Similarly, ELISA revealed high levels of antibodies pretreatment, which gradually declined during treatment and increased slightly 8 months post-treatment cessation. The cat remained PCR positive for CMhm and Hepatozoon species throughout the study. There was no clinical evidence of relapse 24 months post-treatment. Relevance and novel information To our knowledge, this is the first clinical report of a cat with leishmaniosis with H felis and CMhm coinfections. The high L infantum DNA levels post-treatment cessation might indicate that although the lesions had resolved, prolonged or an alternative treatment could have been considere

The changing GMC population in galaxy interactions

This is the final version. Available from OUP via the DOI in this recordWith the advent of modern observational efforts providing extensive giant molecular cloud catalogues, understanding the evolution of such clouds in a galactic context is of prime importance. While numerous previous numerical and theoretical works have focused on the cloud properties in isolated discs, few have looked into the cloud population in an interacting disc system. We present results of the first study investigating the evolution of the cloud population in galaxy experiencing an M51-like tidal fly-by using numerical simulations including star formation, interstellar medium cooling, and stellar feedback. We see the cloud population shift to large unbound clouds in the wake of the companion passage, with the largest clouds appearing as fleeting short-lived agglomerations of smaller clouds within the tidal spiral arms, brought together by large-scale streaming motions. These are then sheared apart as they leave the protection of the spiral arms. Clouds appear to lead diverse lives, even within similar environments, with some being born from gas shocked by filaments streaming into the spiral arms, and others from effectively isolated smaller colliding pairs. Overall, this cloud population produces a shallower mass function than the disc in isolation, especially in the arms compared to the inter-arm regions. Direct comparisons to M51 observations show similarities between cloud populations, though models tailored to the mass and orbital models of M51 appear necessary to precisely reproduce the cloud population