High-energy astrophysics - II. Compact binary stars

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Personal History of Violence and Response to Violence: A Quantitative and Free-Response Study Focusing on College-Age Students

This study examined the relationship between people’s history with violence and how they responded to a graphically violent real-life video. A review of the literature revealed there had been extensive research done about the effects of media and violence on individuals, yet there is a lack of evidence about the effect that violent home footage can have on college-aged students. This relational study utilized a questionnaire that included both a Likert scale and a free-response portion with 25 undergraduate students rating their relationship with violence in the past and their response to a violent video. Greater prior exposure to violence was associated with more extreme responses to violent videos. Suggestions are made for further research involving a larger study utilizing different types of violence recorded in real-life situations

Superhumps in V348 Pup

The eclipsing novalike cataclysmic variable star V348 Pup exhibits a persistent luminosity modulation with a period 6 per cent longer than its 2.44 hour orbital-period (Porb). This has been interpreted as a `positive superhump' resulting from a slowly precessing non-axisymmetric accretion disc gravitationally interacting with the secondary. We find a clear modulation of mid-eclipse times on the superhump period, which agrees well with the predictions of a simple precessing eccentric disc model. Our modelling shows that the disc light centre is on the far side of the disc from the donor star when the superhump reaches maximum light. This phasing suggests a link between superhumps in V348 Pup and late superhumps in SU UMa systems. Modelling of the full lightcurve and maximum entropy eclipse mapping both show that the disc emission is concentrated closer to the white dwarf at superhump maximum than at superhump minimum. We detect additional signals consistent with the beat periods between the implied disc precession period and both (1/2)Porb and (1/3)Porb.Comment: 13 pages, 13 figures, accepted for publication in MNRA

Black hole hunting in the Andromeda Galaxy

We present a new technique for identifying stellar mass black holes in low mass X-ray binaries (LMXBs), and apply it to XMM-Newton observations of M31. We examine X-ray time series variability seeking power density spectra (PDS) typical of LMXBs accreting at a low accretion rate (which we refer to as Type A PDS); these are very similar for black hole and neutron star LMXBs. Galactic neutron star LMXBs exhibit Type A PDS at low luminosities (~10^36--10^37 erg/s) while black hole LMXBs can exhibit them at luminosities >10^38 erg/s. We propose that Type A PDS are confined to luminosities below a critical fraction of the Eddington limit, $l_c$ that is constant for all LMXBs; we have examined asample of black hole and neutron star LMXBs and find they are all consistent with $l_c$ = 0.10+/-0.04 in the 0.3--10 keV band. We present luminosity and PDS data from 167 observations of X-ray binaries in M31 that provide strong support for our hypothesis. Since the theoretical maximum mass for a neutron star is \~3.1 M_Sun, we therefore assert that any LMXB that exhibits a Type A PDS at a 0.3--10 keV luminosity greater than 4 x 10^37 erg/s is likely to contain a black hole primary. We have found eleven new black hole candidates in M31 using this method. We focus on XMM-Newton observations of RX J0042.4+4112, an X-ray source in M31 and find the mass of the primary to be 7+/-2 M_Sun, if our assumptions are correct. Furthermore, RX J0042.4+4112 is consistently bright in \~40 observations made over 23 years, and is likely to be a persistently bright LMXB; by contrast all known Galactic black hole LMXBs are transient. Hence our method may be used to find black holes in known, persistently bright Galactic LMXBs and also in LMXBs in other galaxies.Comment: 6 Pages, 6 figures. To appear in the conference proceedings of "Interacting Binaries: Accretion, Evolution and Outcomes" (Cefalu, July 4-10 2004

Male-Female Differences and Media Consumption in Australia's Wartime Election of 2001

Research consistently shows that western women are not only less supportive of wars than men, but the anti-war, anti-violence stance is among the most marked of gender differences - especially when such issues are salient. Moreover, a substantial number of studies show women to be more caring than men about the well-being of the human race. This paper uses the 2001 Australian Election Study (AES) to test the degree to which these findings gel with what occurred in the Australian national election on 10th November. It also focuses on the influence of media consumption as an explanatory factor. The traditional five-week campaign was dominated by two extraordinary occurrences: the 'war against terrorism', for which Australia was amongst the first American allies to offer military support; and the arrival of boat loads of (mostly middle-eastern) asylum seekers that began several weeks before the election date was announced . Both of Australia's two major political 'parties' - the Liberal-National Coalition and the Australian Labor Party - supported involvement in the 'war against terrorism' and both took a strong stance against asylum seekers. In the main this paper finds these political policy decisions did not alienate women. Contrary to conventional wisdom, relatively few women (and equal to the proportion of men) expressed concern about Australia's support for the 'fight against terrorism'. There was also substantial support for, and little difference in male-female attitudes about turning asylum seekers back. However, a traditional gender gap emerged on the question of Australia's provision of actual military assistance for the war. Even so, a majority of men and women supported the decision, and the gender gap in attitude was absorbed in the uncommitted category rather than being a matter of disagreement with the decision to send Australian troops. The media's extensive coverage - which frequently kept other campaign issues out of the headlines - appears to have contributed to these unusual findings