(Dis)located Olympic patriots: sporting connections, administrative communications and imperial ether in interwar New Zealand

During the interwar period (1919-1939) protagonists of the early New Zealand Olympic Committee NZOC worked to renegotiate and improve the country's international sporting participation and involvement in the International Olympic Committee IOC. To this end, NZOC effectively used its locally based administrators and well-placed expatriates in Britain to variously assert the organisation's nascent autonomy, independence and political power, progress Antipodean athlete's causes, and, counter any potential doubt about the nation's peripheral position in imperial sporting dialogues. Adding to the corpus of scholarship on New Zealand's ties and tribulations with imperial Britain (in and beyond sport) (e.g. Beilharz and Cox 2007; Belich 2001, 2007; Coombes 2006; MacLean 2010; Phillips 1984, 1987; Ryan 2004, 2005, 2007), in this paper I examine how the political actions and strategic location of three key NZOC agents (specifically, administrator Harry Amos and expatriates Arthur Porritt and Jack Lovelock) worked in their own particular ways to assert the position of the organisation within the global Olympic fraternity. I argue that the efforts of Amos, Porritt and Lovelock also concomitantly served to remind Commonwealth sporting colleagues (namely Britain and Australia) that New Zealand could not be characterised as, or relegated to being, a distal, subdued, or subservient colonial sporting partner. Subsequently I contend that NZOC's development during the interwar period, and particularly the utility of expatriate agents, can be contextualised against historiographical shifts that encourage us to rethink, reimagine, and rework narratives of empire, colonisation, national identity, commonwealth and belonging

Playing on common ground: Spaces of sport, education and corporate connectivity, contestation and creativity

In this article we examine connectivities within the ‘messy’ organizational commons of sport, education and corporate partnerships. As scholars forewarn, there are currently key stakeholders within the commons that that have set agendas, occupied ideological and physical terrain, and legitimized a presence and authority. The intertwining of organizations here is an evident function of an increased symbiosis between sport, education and governmental and non-governmental stakeholders to carve out significant sector spaces, and exert authority and power over the creation, implementation and ownership ‘collaborative’ and intersectional work. Drawing on spatial theorists, Henri Lefebvre and Yi Fu Tuan, and examples from FIFA and the IOC, we present a conceptual framework of global stakeholder relations. Focusing of processes of thought, production and action, we offer an intersectional critique of the nuances of Sport–Corporate–Education nexus and consider possibilities and potential for sport education spaces to be reconfigured ane

<i>Spitzer</i> Microlensing Parallax Reveals Two Isolated Stars in the Galactic Bulge

We report the mass and distance measurements of two single-lens events from the 2017 $\textit {Spitzer}$ microlensing campaign. The ground-based observations yield the detection of finite-source effects, and the microlens parallaxes are derived from the joint analysis of ground-based observations and $\textit {Spitzer}$ observations. We find that the lens of OGLE-2017-BLG-1254 is a 0.60 ± 0.03 M ⊙ star with D LS = 0.53 ± 0.11 kpc, where D LS is the distance between the lens and the source. The second event, OGLE-2017-BLG-1161, is subject to the known satellite parallax degeneracy, and thus is either a ${0.51}_{-0.10}^{+0.12}\,{M}_{\odot }$ star with D LS = 0.40 ± 0.12 kpc or a ${0.38}_{-0.12}^{+0.13}\,{M}_{\odot }$ star with D LS = 0.53 ± 0.19 kpc. Both of the lenses are therefore isolated stars in the Galactic bulge. By comparing the mass and distance distributions of the eight published $\textit {Spitzer}$ finite-source events with the expectations from a Galactic model, we find that the $\textit {Spitzer}$ sample is in agreement with the probability of finite-source effects occurring in single-lens events

Spitzer Microlensing Parallax for OGLE-2017-BLG-0896 Reveals a Counter-rotating Low-mass Brown Dwarf

The kinematics of isolated brown dwarfs in the Galaxy, beyond the solar neighborhood, is virtually unknown. Microlensing has the potential to probe this hidden population, as it can measure both the mass and five of the six phase-space coordinates (all except the radial velocity) even of a dark isolated lens. However, the measurements of both the microlens-parallax and finite-source effects are needed in order to recover the full information. Here, we combine the Spitzer satellite parallax measurement with the ground-based light curve, which exhibits strong finite-source effects, of event OGLE-2017-BLG-0896. We find two degenerate solutions for the lens (due to the known satellite-parallax degeneracy), which are consistent with each other except for their proper motion. The lens is an isolated brown dwarf with a mass of either 18 ± 1 M J or 20 ± 1 M J . This is the lowest isolated-object mass measurement to date, only ~45% more massive than the theoretical deuterium-fusion boundary at solar metallicity, which is the common definition of a free-floating planet. The brown dwarf is located at either 3.9 ± 0.1 kpc or 4.1 ± 0.1 kpc toward the Galactic bulge, but with proper motion in the opposite direction of disk stars, with one solution suggesting it is moving within the Galactic plane. While it is possibly a halo brown dwarf, it might also represent a different, unknown population

A Universal Power-law Prescription for Variability from Synthetic Images of Black Hole Accretion Flows

We present a framework for characterizing the spatiotemporal power spectrum of the variability expected from the horizon-scale emission structure around supermassive black holes, and we apply this framework to a library of general relativistic magnetohydrodynamic (GRMHD) simulations and associated general relativistic ray-traced images relevant for Event Horizon Telescope (EHT) observations of Sgr A*. We find that the variability power spectrum is generically a red-noise process in both the temporal and spatial dimensions, with the peak in power occurring on the longest timescales and largest spatial scales. When both the time-averaged source structure and the spatially integrated light-curve variability are removed, the residual power spectrum exhibits a universal broken power-law behavior. On small spatial frequencies, the residual power spectrum rises as the square of the spatial frequency and is proportional to the variance in the centroid of emission. Beyond some peak in variability power, the residual power spectrum falls as that of the time-averaged source structure, which is similar across simulations; this behavior can be naturally explained if the variability arises from a multiplicative random field that has a steeper high-frequency power-law index than that of the time-averaged source structure. We briefly explore the ability of power spectral variability studies to constrain physical parameters relevant for the GRMHD simulations, which can be scaled to provide predictions for black holes in a range of systems in the optically thin regime. We present specific expectations for the behavior of the M87* and Sgr A* accretion flows as observed by the EHT

Millimeter Light Curves of Sagittarius A* Observed during the 2017 Event Horizon Telescope Campaign

The Event Horizon Telescope (EHT) observed the compact radio source, Sagittarius A* (Sgr A*), in the Galactic Center on 2017 April 5–11 in the 1.3 mm wavelength band. At the same time, interferometric array data from the Atacama Large Millimeter/submillimeter Array and the Submillimeter Array were collected, providing Sgr A* light curves simultaneous with the EHT observations. These data sets, complementing the EHT very long baseline interferometry, are characterized by a cadence and signal-to-noise ratio previously unattainable for Sgr A* at millimeter wavelengths, and they allow for the investigation of source variability on timescales as short as a minute. While most of the light curves correspond to a low variability state of Sgr A*, the April 11 observations follow an X-ray flare and exhibit strongly enhanced variability. All of the light curves are consistent with a red-noise process, with a power spectral density (PSD) slope measured to be between −2 and −3 on timescales between 1 minute and several hours. Our results indicate a steepening of the PSD slope for timescales shorter than 0.3 hr. The spectral energy distribution is flat at 220 GHz, and there are no time lags between the 213 and 229 GHz frequency bands, suggesting low optical depth for the event horizon scale source. We characterize Sgr A*'s variability, highlighting the different behavior observed just after the X-ray flare, and use Gaussian process modeling to extract a decorrelation timescale and a PSD slope. We also investigate the systematic calibration uncertainties by analyzing data from independent data reduction pipelines

Selective Dynamical Imaging of Interferometric Data

Recent developments in very long baseline interferometry (VLBI) have made it possible for the Event Horizon Telescope (EHT) to resolve the innermost accretion flows of the largest supermassive black holes on the sky. The sparse nature of the EHT's (u, v)-coverage presents a challenge when attempting to resolve highly time-variable sources. We demonstrate that the changing (u, v)-coverage of the EHT can contain regions of time over the course of a single observation that facilitate dynamical imaging. These optimal time regions typically have projected baseline distributions that are approximately angularly isotropic and radially homogeneous. We derive a metric of coverage quality based on baseline isotropy and density that is capable of ranking array configurations by their ability to produce accurate dynamical reconstructions. We compare this metric to existing metrics in the literature and investigate their utility by performing dynamical reconstructions on synthetic data from simulated EHT observations of sources with simple orbital variability. We then use these results to make recommendations for imaging the 2017 EHT Sgr A* data set

Myoidema

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