The Origin of Double-Peaked Narrow Lines in Active Galactic Nuclei III: Feedback from Biconical AGN Outflows

We apply an analytic Markov Chain Monte Carlo model to a sample of 18 AGN-driven biconical outflows that we identified from a sample of active galaxies with double-peaked narrow emission lines at z < 0.1 in the Sloan Digital Sky Survey. We find that 8/18 are best described as asymmetric bicones, 8/18 are nested bicones, and 2/18 are symmetric bicones. From the geometry and kinematics of the models, we find that these moderate-luminosity AGN outflows are large and energetic. The biconical outflows axes are randomly oriented with respect to the photometric major axis of the galaxy, implying a randomly oriented and clumpier torus to collimate the outflow, but the torus also allows some radiation to escape equatorially. We find that 16/18 (89%) outflows are energetic enough to drive a two-staged feedback process in their host galaxies. All of these outflows geometrically intersect the photometric major axis of the galaxy, and 23% of outflow host galaxies are significantly redder or have significantly lower specific star formation rates when compared to a matched sample of active galaxies.Comment: 32 pages, 11 figures, accepted for publication in MNRAS; See Figure 7 for a summary of the finding

Examining Disclosure Risk and Data Utility: An Administrative Data Case Study

The plethora of new data sources, combined with a growing interest in increased access to previously unpublished data, poses a set of ethical challenges regarding individual privacy. This paper sets out one aspect of those challenges: the need to anonymise data in such a form that protects the privacy of individuals while providing sufficient data utility for data users. This issue is discussed using a case study of Scottish Government’s administrative data, in which disclosure risk is examined and data utility is assessed using a potential ‘real-world’ analysis

Statistical disclosure control: an interdisciplinary approach to the problem of balancing privacy risks and data utility

The recent increase in the availability of data sources for research has put significant strain on existing data management work-flows, especially in the field of statistical disclosure control. New statistical methods for disclosure control are frequently set out in the literature, however, few of these methods become functional implementations for data owners to utilise. Current workflows often provide inconsistent results dependent on ad hoc approaches, and bottlenecks can form around statistical disclosure control checks which prevent research from progressing. These problems contribute to a lack of trust between researchers and data owners and contribute to the under utilisation of data sources. This research is an interdisciplinary exploration of the existing methods. It hypothesises that algorithms which invoke a range of statistical disclosure control methods (recoding, suppression, noise addition and synthetic data generation) in a semi-automatic way will enable data owners to release data with a higher level of data utility without any increase in disclosure risk when compared to existing methods. These semi-automatic techniques will be applied in the context of secure data-linkage in the e-Health sphere through projects such as DAMES and SHIP. This thesis sets out a theoretical framework for statistical disclosure control and draws on qualitative data from data owners, researchers, and analysts. With these contextual frames in place, the existing literature and methods were reviewed, and a tool set for implementing k-anonymity and a range of disclosure control methods was created. This tool-set is demonstrated in a standard workflow and it is shown how it could be integrated into existing e-Science projects and governmental settings. Comparing this approach with existing workflows within the Scottish Government and NHS Scotland, it allows data owners to process queries from data users in a semi-automatic way and thus provides for an enhanced user experience. This utility is drawn from the consistency and replicability of the approach combined with the increase in the speed of query processing

Online allies and tricky freelancers: understanding the differences in the role of social media in the campaigns for the Scottish Independence Referendum

Using the 2014 Scottish independence referendum as a case study, this article asks first, to what extent is the use of digital communications technologies, in particular social media, associated with fundamental changes to campaign organizations, specifically to the command and control model? Second, under what conditions are challenges to the model more likely to emerge? Using mixed methods, our analysis of the case demonstrates that radical organizational or strategic change is not inevitable, nor is there a one-size-fits-all approach. Technologies are not ‘just tools’ that any campaign with enough resources will adopt in similar ways. Instead, depending on a number of interdependent factors (i.e. context, resources, strategy, organizational structure and culture), some campaigns – like Better Together – selectively adopt digital tools that fit with the command and control model; in other cases – like Yes Scotland – the application of digital communications technologies and the dynamics created by linking to other (digital-enabled) grassroots organizations can have transformative effects

The Origin of Double-peaked Narrow Lines in Active Galactic Nuclei. IV. Association with Galaxy Mergers

Double-peaked narrow emission lines in active galactic nucleus (AGN) spectra can be produced by AGN outflows, rotation, or dual AGNs, which are AGN pairs in ongoing galaxy mergers. Consequently, double-peaked narrow AGN emission lines are useful tracers of the coevolution of galaxies and their supermassive black holes, as driven by AGN feedback and AGN fueling. We investigate this concept further with follow-up optical longslit observations of a sample of 95 Sloan Digital Sky Survey (SDSS) galaxies that have double-peaked narrow AGN emission lines. Based on a kinematic analysis of the longslit spectra, we confirm previous work that finds that the majority of double-peaked narrow AGN emission lines are associated with outflows. We also find that eight of the galaxies have companion galaxies with line-of-sight velocity separations < 500 km/s and physical separations <30 kpc. Since we find evidence of AGNs in both galaxies, all eight of these systems are compelling dual AGN candidates. Galaxies with double-peaked narrow AGN emission lines occur in such galaxy mergers at least twice as often as typical active galaxies. Finally, we conclude that at least 3% of SDSS galaxies with double-peaked narrow AGN emission lines are found in galaxy mergers where both galaxies are resolved in SDSS imaging.Comment: 14 pages, 2 figures, ApJ in pres

Meritocracy and the inheritance of advantage

We present a model where more accurate information on the background of individuals facilitates statistical discrimination, increasing inequality and intergenerational persistence in income. Surprisingly, more accurate information on the actual capabilities of workers leads to the same result - firms give increased weight to the more accurate information, increasing inequality, which itself fosters discrimination. The rich take advantage of this through educational investments in their children, and mobility decreases as a consequence of an increase in the ability to reward talent. Using our model to interpret the data suggests that a country like the US might indeed be a land of opportunity for the sufficiently able, as conditional on ability background may have relatively little effect. Nevertheless the US has a relatively low degree of intergenerational mobility precisely because meritocracy facilitates a high correlation of ability with background

Collaborative systems for enhancing the analysis of social surveys: the grid enabled specialist data environments

This paper describes a group of online services which are designed to support social survey research and the production of statistical results. The 'Grid Enabled Specialist Data Environment' (GESDE) services constitute three related systems which offer facilities to search for, extract and exploit supplementary data and metadata concerned with the measurement and operationalisation of survey variables. The services also offer users the opportunity to deposit and distribute their own supplementary data resources for the benefit of dissemination and replication of the details of their own analysis. The GESDE services focus upon three application areas: specialist data relating to the measurement of occupations; educational qualifications; and ethnicity (including nationality, language, religion, national identity). They identify information resources related to the operationalisation of variables which seek to measure each of these concepts - examples include coding frames, crosswalk and translation files, and standardisation and harmonisation recommendations. These resources constitute important supplementary data which can be usefully exploited in the analysis of survey data. The GESDE services work by collecting together as much of this supplementary data as possible, and making it searchable and retrievable to others. This paper discusses the current features of the GESDE services (which have been designed as part of a wider programme of ‘e-Science’ research in the UK), and considers ongoing challenges in providing effective support for variable-oriented statistical analysis in the social sciences