Determination of Lens Mass Density Profile from Strongly-Lensed Gravitational-Wave Signals

As the interferometers detecting gravitational waves are upgraded, improving their sensitivity, the probability of observing strong lensing increases. Once a detection is made, it will be critical to gain as much information as possible about the lensing object from these observations. In this work, we present a methodology to rapidly perform model selection between differing mass density profiles for strongly lensed gravitational wave signals, using the results of the fast strong lensing analysis pipeline GOLUM. We demonstrate the validity of this methodology using some illustrative examples adopting the idealised singular isothermal sphere and point mass lens models. We take several simulated lensed signals, analyse them with GOLUM and subject them to our methodology to recover both the model and its parameters. To demonstrate the methodology's stability, we show how the result varies with the number of samples used for a subset of these injections. In addition to the analysis of simulations, we also apply our methodology to the gravitational wave event pair GW191230--LGW200104, two events with similar frequency evolutions and sky locations, which was analysed in detail as a potential lensing candidate but ultimately discarded when considering the full population and the uncertain nature of the second event. We find a preference for the singular isothermal sphere model over the point mass, though our posteriors are much wider than for the lensed injections, in line with the expectations for a non-lensed event. The methodology developed in this work is made available as part of the Gravelamps package of software.Comment: 12 pages, 6 figures. Updated to address referee comment

Gravelamps: gravitational wave lensing mass profile model selection

We present the package Gravelamps, which is designed to analyze gravitationally lensed gravitational wave signals in order to constrain the mass density profile of the lensing object. Gravelamps does this via parameter estimation using the framework of bilby, which enables estimation of both the lens and the source parameters. The package can be used to study both microlensing and macrolensing cases, where the lensing mass distribution is described by a point-mass and extended-mass density profile, respectively. It allows the user to easily and freely switch between a full wave optics and approximate geometric optics description. The performance of Gravelamps is demonstrated via simulated analysis of both microlensing and macrolensing events, illustrating its capability for both parameter estimation and model selection in the wave optics and hybrid environments. To further demonstrate the utility of the package, the real gravitational-wave event GW170809 was analyzed using Gravelamps; this event was found to yield no strong evidence supporting the lensing hypothesis, consistent with previously published results

Gravelamps: gravitational wave lensing mass profile model selection

We present the package Gravelamps, which is designed to analyze gravitationally lensed gravitational wave signals in order to constrain the mass density profile of the lensing object. Gravelamps does this via parameter estimation using the framework of bilby, which enables estimation of both the lens and the source parameters. The package can be used to study both microlensing and macrolensing cases, where the lensing mass distribution is described by a point-mass and extended-mass density profile, respectively. It allows the user to easily and freely switch between a full wave optics and approximate geometric optics description. The performance of Gravelamps is demonstrated via simulated analysis of both microlensing and macrolensing events, illustrating its capability for both parameter estimation and model selection in the wave optics and hybrid environments. To further demonstrate the utility of the package, the real gravitational-wave event GW170809 was analyzed using Gravelamps; this event was found to yield no strong evidence supporting the lensing hypothesis, consistent with previously published results

Looking back, looking forward: recovery journeys in a high secure hospital

A qualitative study of staff and service users’ views of recovery was undertaken in a UK high secure hospital working to implement recovery practices. 30 staff and 25 service users participated in semi-structured interviews or focus groups. Thematic analysis identified four broad accounts of how recovery was made sense of in the high secure environment: the importance of meaningful occupation; valuing relationships; recovery journeys and dialogue with the past; and recovery as personal responsibility. These themes are discussed with an emphasis on service user strategies of cooperation or resistance, respectively advancing or impeding progress through the system. In this context the notion of cooperation is, for many, commensurate with compliance with a dominant medical model. The policy framing of recovery opens up contemplation of treatment alternatives, more participatory approaches to risk management, and emphasise the value of relational skills, but may not elude the overarching bio-psychiatric episteme

A horizon scan of global conservation issues for 2014

This paper presents the output of our fifth annual horizon-scanning exercise, which aims to identify topics that increasingly may affect conservation of biological diversity, but have yet to be widely considered. A team of professional horizon scanners, researchers, practitioners, and a journalist identified 15 topics which were identified via an iterative, Delphi-like process. The 15 topics include a carbon market induced financial crash, rapid geographic expansion of macroalgal cultivation, genetic control of invasive species, probiotic therapy for amphibians, and an emerging snake fungal disease. © 2013 Elsevier Ltd

Community Service: Editor pride and user preference on local newspaper websites

Armed with readily accessible online traffic logs that provide detailed information about the items users are selecting to view, editors are voicing concern about the potential effect on their own content decisions. Through a survey of local British newspaper editors, this article examines the overlap between user preferences, as suggested by assessments of website traffic, and content that editors identify as their best. Results are considered in the context of two related subsets of agenda-setting theory, as well as the sociological process of “making news.” The study finds overlap between broad categories of stories preferred by editors and users, but a considerable disconnect over the nature of the items within those categories

Follow-up analyses to the O3 LIGO-Virgo-KAGRA lensing searches

Along their path from source to observer, gravitational waves may be gravitationally lensed by massive objects. This results in distortions of the observed signal which can be used to extract new information about fundamental physics, astrophysics, and cosmology. Searches for these distortions amongst the observed signals from the current detector network have already been carried out, though there have as yet been no confident detections. However, predictions of the observation rate of lensing suggest detection in the future is a realistic possibility. Therefore, preparations need to be made to thoroughly investigate the candidate lensed signals. In this work, we present some of the follow-up analyses and strategies that could be applied to assess the significance of such events and ascertain what information may be extracted about the lens-source system from such candidate signals by applying them to a number of O3 candidate events, even if these signals did not yield a high significance for any of the lensing hypotheses. For strongly-lensed candidates, we verify their significance using a background of simulated unlensed events and statistics computed from lensing catalogs. We also look for potential electromagnetic counterparts. In addition, we analyse in detail a candidate for a strongly-lensed sub-threshold counterpart that is identified by a new method. For microlensing candidates, we perform model selection using a number of lens models to investigate our ability to determine the mass density profile of the lens and constrain the lens parameters. We also look for millilensing signatures in one of the lensed candidates. Applying these additional analyses does not lead to any additional evidence for lensing in the candidates that have been examined. However, it does provide important insight into potential avenues to deal with high-significance candidates in future observations.Comment: 34 pages, 27 figure

Reclaiming the humanity in personality Disorder.

This paper provides a commentary upon the nursing care of individuals diagnosed with personality disorder and associated education courses. The discussion focuses upon recent policy trends in the UK as a point of departure. This policy discourse is critical of mainstream mental health services in previously operating to exclude such individuals. One of the consequences has been a recent growth in interest in relevant training courses, many of which devote significant attention to staff attitudes regarding this client group. Various previous researchers and commentators have remarked upon the implications for practice of a perceived negative attitude among care staff. We reflect upon our own anecdotal experience of developing and delivering new university-based courses for practitioners working in the field of personality disorder to offer a particular critique of the UK context, in which this policy, training, and practice is framed. Social constructionist theories are drawn on to offer insights into public and practitioner discourse and the possible effects on therapeutic relationships. The available discourse constructs individuals with a diagnosis of personality disorder as essentially different from other people. We argue that staff training and practice development initiatives are likely to be more successful if such discourse is challenged, and attempts are made in therapeutic encounters to recognize shared characteristics and positive attributes as much as perceived difference and negative attributes. We refer to this as a re-engagement with common humanity. Despite the singular national context, the discursive themes explored are not necessarily restricted to the UK