Orbits of Globular Clusters in the Outer Galaxy: NGC 7006

We present a proper motion study of the distant globular cluster NGC 7006 based on the measurement of 25 photographic plates spanning a 40-year interval. The absolute proper motion determined with respect to extragalactic objects is (-0.96, -1.14) +- (0.35, 0.40) mas/yr. The total space velocity of NGC 7006 in a Galactocentric rest frame is 279 km/s, placing the cluster on one of the most energetic orbits (Ra =102 kpc) known to date for clusters within 40-kpc from the Galactic center. We compare the orbits of four clusters that have apocentric radii larger than 80 kpc (NGC 5466, NGC 6934, NGC 7006 and Pal 13) with those of Galactic satellites with well-measured proper motions. These clusters have orbits that are highly eccentric and of various inclinations with respect to the Galactic plane. In contrast, the orbits of the Galactic satellites are of low to moderate eccentricity and highly inclined. Based on orbit types, chemical abundances and cluster parameters, we discuss the properties of the hypothetical host systems of the remote globular clusters in the Searle-Zinn paradigm. It is apparent that clusters such as NGC 5466, NGC 6934 and NGC 7006 formed in systems that more likely resemble the Fornax dSph, rather than the Sagittarius dSph. We also discuss plausible causes for the difference found so far between the orbit type of outer halo clusters and that of Galactic satellites and for the tentative, yet suggestive phase-space scatter found among outer halo clusters.Comment: 27 pages, 5 figures, to be published in the Astronomical Journa

The Absolute Proper Motion of Palomar 12: A Case for Tidal Capture from the Sagittarius Dwarf Spheroidal Galaxy

We have measured the absolute proper motion of the young globular cluster Pal 12 with respect to background galaxies, using plate material spanning a 40-year time baseline, and measuring stars down to a magnitude V~22. The measured absolute proper motion has an uncertainty of 0.3 mas/yr in each coordinate. Pal 12's young age for a globular cluster led to the hypothesis that the cluster originated in the Large Magellanic Cloud (LMC) and was later captured by the Milky Way (Lin and Richer 1992). Here we investigate this hypothesis using the complete kinematical data. We present the orbital characteristics of Pal 12 and compare them with those of the LMC and Sagittarius dwarf galaxy (Sgr). The present kinematical data suggest that, from the two parent candidates for Pal 12, Sgr presents a more plausible case for the host galaxy than the LMC. We explore this scenario in the context of the uncertainties in the orbits and using two different analyses: the direct comparison of the orbits of Pal 12 and Sgr as a function of time, and the analytical model of Sgr's tidal disruption developed by Johnson (1998). We find that, within the present uncertainties of the observables, this scenario is viable in both methods. Moreover, both methods place this event at the same point in time. Our best estimate of the time of Pal 12's tidal capture from Sgr is ~ 1.7 Gyr ago.Comment: 37 pages, 5 tables, 5 figures, accepted for publication in AJ, Oct. 200

Proper Motion Study of the Magellanic Clouds using SPM material

Absolute proper motions are determined for stars and galaxies to V=17.5 over a 450 square-degree area that encloses both Magellanic Clouds. The proper motions are based on photographic and CCD observations of the Yale/San Juan Southern Proper Motion program, which span over a baseline of 40 years. Multiple, local relative proper motion measures are combined in an overlap solution using photometrically selected Galactic Disk stars to define a global relative system that is then transformed to absolute using external galaxies and Hipparcos stars to tie into the ICRS. The resulting catalog of 1.4 million objects is used to derive the mean absolute proper motions of the Large Magellanic Cloud and the Small Magellanic Cloud; (\mu_\alpha\cos\delta,\mu_\delta)_{LMC}=(1.89,+0.39)\pm (0.27,0.27)\;\;\{mas yr}^{-1} and (\mu_\alpha\cos\delta,\mu_\delta)_{SMC}=(0.98,-1.01)\pm (0.30,0.29)\;\;\{mas yr}^{-1}. These mean motions are based on best-measured samples of 3822 LMC stars and 964 SMC stars. A dominant portion (0.25 mas yr$^{-1}$) of the formal errors is due to the estimated uncertainty in the inertial system of the Hipparcos Catalog stars used to anchor the bright end of our proper motion measures. A more precise determination can be made for the proper motion of the SMC {\it relative} to the LMC; (\mu_{\alpha\cos\delta},\mu_\delta)_{SMC-LMC} = (-0.91,-1.49) \pm (0.16,0.15)\;\;\{mas yr}^{-1}. This differential value is combined with measurements of the proper motion of the LMC taken from the literature to produce new absolute proper-motion determinations for the SMC, as well as an estimate of the total velocity difference of the two clouds to within $\pm$54 kms$^{-1}$.Comment: 50 pages (referee format), 13 figures. Accepted for publication in A

Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study

Purpose: Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods: Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results: The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion: We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Airline pilot situation awareness: presenting a conceptual model for meta-cognition, reflection and education

The dissertation research summarized here, utilized the Grounded Theory Method to develop a conceptual model of pilot situation awareness from 223 Aviation Safety Reporting System (ASRS) narratives. The application of Latent Semantic Analysis aided the theoretical sampling of ASRS reports. A multistage model was developed involving attention, perception, interpretation, decision making, and action in support of goal-driven behavior. Narrative report coding identified several categories of situation awareness elements that pilots direct their attention to in building and maintaining situation awareness. Internal to the aircraft, flight crews directed their attention to the aircraft’s flight state and automation state. They also directed their attention to the condition of the aircraft, the functioning of the crew, and the status of the cabin. External to the aircraft, flight crews directed their attention to airport conditions, air traffic control, terrain, traffic, and weather. Pilots were also aware of the passage of time. Twelve characteristics of situation awareness were identified from narrative report coding which were subsequently compared with existing theoretical perspectives of situation awareness

Brief Note: Spergularia Marina, A New Species Record for the Flora of Ohio

Author Institution: Department of Botany, Ohio Universit