Controversies in the History of the Radiation Reaction problem in General Relativity

This paper examines the historical controversy over whether gravitationally bound systems, such as binary stars, experienced orbital damping due to the emission of gravitational radiation, focusing especially on the period of the 1950s, but also discussing the work of Einstein and Rosen in the 1930s on cylindrical gravitational waves and the later quadrupole formula controversy.Comment: 33 pages, Late

Relativistic Lighthouses: The Role of the Binary Pulsar in proving the existence of Gravitational Waves

This paper discusses the role of the discovery and analysis of the first binary pulsar in settling the long-running quadrupole formula controversy over the status of gravitational waves as a prediction of general relativity. It also discusses how we should understand the resolution of this controversy in the context of the so-called science wars. In other words it discusses whether concepts such as interpretive flexibility and the experimenters' regress can shed light on what can also be seen as a classical confirmation of realist expectations, in which a theoretical controversy is settled by a conclusive experiment.Comment: 28 pages, no figures, presented at a 1998 conference in Mainz on the History of General Relativit

Zoom and whirl: Eccentric equatorial orbits around spinning black holes and their evolution under gravitational radiation reaction

We study eccentric equatorial orbits of a test-body around a Kerr black hole under the influence of gravitational radiation reaction. We have adopted a well established two-step approach: assuming that the particle is moving along a geodesic (justifiable as long as the orbital evolution is adiabatic) we calculate numerically the fluxes of energy and angular momentum radiated to infinity and to the black hole horizon, via the Teukolsky-Sasaki-Nakamura formalism. We can then infer the rate of change of orbital energy and angular momentum and thus the evolution of the orbit. The orbits are fully described by a semilatus rectum p and an eccentricity e. We find that while, during the inspiral, e decreases until shortly before the orbit reaches the separatrix of stable bound orbits [which is defined by p(s)(e)], in many astrophysically relevant cases the eccentricity will still be significant in the last stages of the inspiral. In addition, when a critical value p(crit)(e) is reached, the eccentricity begins to increase as a result of continued radiation induced inspiral. The two values p(s), p(crit) (for given e) move closer to each other, in coordinate terms, as the black hole spin is increased, as they do also for fixed spin and increasing eccentricity. Of particular interest are moderate and high eccentricity orbits around rapidly spinning black holes, with p(e)approximate top(s)(e). We call these "zoom-whirl" orbits, because of their characteristic behavior involving several revolutions around the central body near periastron. Gravitational waveforms produced by such orbits are calculated and shown to have a very particular signature. Such signals may well prove of considerable astrophysical importance for the future Laser Interferometer Space Antenna detector

Identification of Outflows and Candidate Dual Active Galactic Nuclei in SDSS Quasars at z=0.8-1.6

We present a sample of 131 quasars from the Sloan Digital Sky Survey at redshifts 0.8<z<1.6 with double peaks in either of the high-ionization narrow emission lines [NeV]3426 or [NeIII]3869. These sources were selected with the intention of identifying high-redshift analogs of the z<0.8 active galactic nuclei (AGN) with double-peaked [OIII]5007 lines, which might represent AGN outflows or dual AGN. Lines of high-ionization potential are believed to originate in the inner, highly photoionized portion of the narrow line region (NLR), and we exploit this assumption to investigate the possible kinematic origins of the double-peaked lines. For comparison, we measure the [NeV]3426 and [NeIII]3869 double peaks in low-redshift (z<0.8) [OIII]-selected sources. We find that [NeV]3426 and [NeIII]3869 show a correlation between line-splitting and line-width similar to that of [OIII]5007 in other studies; and the velocity-splittings are correlated with the quasar Eddington ratio. These results suggest an outflow origin for at least a subset of the double-peaks, allowing us to study the high-ionization gas kinematics around quasars. However, we find that a non-neligible fraction of our sample show no evidence for an ionization stratification. For these sources, the outflow scenario is less compelling, leaving the dual AGN scenario as a viable possibility. Finally, we find that our sample shows an anti-correlation between the velocity-offset ratio and luminosity ratio of the components, which is a potential dynamical argument for the presence of dual AGN. Therefore, this study serves as a first attempt at extending the selection of candidate dual AGN to higher redshifts.Comment: 19 pages, 12 figures, accepted for publication in The Astrophysical Journa

DPP v Hustveit: suspended sentence for rape in Ireland – an appropriate response?

DPP v Husrveit' is the second case since the introduction of s 2 of the Criminal Law (Rape) Act 1981 (section 2 rape) to impose an outright non-custodial sentence for an offence of rape in Ireland.2 The case concerns the repeated rape and sexual assault of a woman by her partner as she slept, often while she was under the influence of prescribed medication which had a sedative effect. The behaviour of the defendant first came to light during the relationship when he admitted to the assaults following a confrontation with the victim and later during an email exchange where the victim asked him to explain his actions. The emails from the defendant detailed how he had raped the victim up to 10 times and touched her in her sleep up to three times per week throughout their relationship. The defendant received a suspended sentence of seven years' imprisonment, having pleaded guilty at the Central Criminal Court to one count of rape and one count of sexual assault between 2011 and 2012. In suspending the sentence, McCarthy J described the circumstances as very exceptional

Towards a more contextual approach to blame attribution: the case of the Diminished Responsibility Offender

With the proliferation of nonstandard crimes which do not appear to have a clear wrongdoer nor a clear wrong, and which do not denote a traditional, capacity based approach to criminal responsibility, there exists a need within criminal law theory to take stock. Many commentators (though not all) yearn for a reaffirmation of the true, moral purpose of the criminal law and a delimitation of its boundaries.1* However, with more formal recognition of an environment outside the criminal law which is ever expanding and mutating, such an ambition is unlikely to materialise. Even scholars such as Victor Tadros, who argues that the ‘central idea of holding an individual responsible’ is, in fact constant or ‘historically stable’,2 acknowledges that this does not entail that the idea of criminal responsibility is historically stable.3 It is argued that a more attainable aim is for clearer insight into the workings and interconnectivity of such aspects, with a view to informing future directions. To this end, this paper argues, (albeit somewhat ambitiously), for a more particularised view of blame and takes the example of the ‘Diminished Responsibility Offender’4 to promote contextualisation both in the structure and substance of the law, based on current trends in criminal law theory, in addition to the behavioural sciences. Examining the issue of criminal responsibility through the lens of a particular type of offender facilitates a deeper, and arguably more tangible, understanding of the nature of the concept. This paper has selected the doctrine of diminished responsibility as a pertinent prototype, given its unique and dichotomous position within the criminal law; it vacillates between presenting itself as a manifestation of the heart of individual responsibility, and existing somewhat on the periphery of the criminal law, as a so called partial defence. Furthermore, it reveals the capacity based approach to criminal responsibility as a legitimating factor of its existence, while concurrently exposing the innate problems pertaining to the same