Evidence for Proportionate Partition Between the Magnetic Field and Hot Gas in Turbulent Cassiopeia A

We present a deep X-ray observation of the young Galactic supernova remnant Cas A, acquired with the ROSAT High Resolution Imager. This high dynamic range (232 ks) image reveals low-surface-brightness X-ray structure, which appears qualitatively similar to corresponding radio features. We consider the correlation between the X-ray and radio morphologies and its physical implications. After correcting for the inhomogeneous absorption across the remnant, we performed a point by point (4" resolution) surface brightness comparison between the X-ray and radio images. We find a strong (r = 0.75) log-log correlation, implying an overall relationship of $\log(\Sigma_{_{\rm X-ray}}) \propto (2.21\pm0.05) \times \log(\Sigma_{_{\rm radio}})$. This is consistent with proportionate partition (and possibly equipartition) between the local magnetic field and the hot gas --- implying that Cas A's plasma is fully turbulent and continuously amplifying the magnetic field.Comment: 8 pages with embedded bitmapped figures, Accepted by ApJ Letters 5/1/9

The analysis of trace metals in surface waters from Scotland and Wales

188 water samples taken from Scottish and Welsh lakes in 1995/6 have been analysed for a range of trace metals, Hg, As, Se, Be, V, Cr, Co, Ni, Cu, Zn, Mo, Ag, Cd, Sb, Ba, Tl, Pb, & Bi. At all sites Hg, As, Se, Be, Bi, Pb and Ag were below limits of detection by the ICP-MS. The other elements showed various geographical distributions. In Wales, the south-central region and Anglesey appeared consistently higher and it is suggested that these are due to former mining and contemporary smelting activities respectively. In Scotland, distributions were move diverse although southern and south-west Scotland often appeared to show elevated levels as did sites on Orkney and Shetland. In general, lake sites in the north-west and Hebrides showed lower concentrations. Pnncipal Components Analysis (PCA) was used to try and determine any patterns in the data, but the results were inconclusive. The PC axes explained little of the variability within the data and clusters of sites on the bi-plots show little in common. However, only geographical location was available to be used m the PCA interpretation and it may be that other factors (lake and catchment characteristics, other water chemistry) would help explain the data more fully. The data included in this report are from smgle water samples taken over a short period of time. Therefore, althougl1 the data may show a useful 'snap-shot' of the situation, more information would be available from analyses of the sediment record (to put the data into temporal context) and other substrates where metal accumulation takes place. This would have the advantage of producing a time averaged metal value, but more importantly would mean more values above analytical detection and hence a better idea of metal distribution

An X-ray upper limit on the presence of a Neutron Star for the Small Magellanic Cloud and Supernova Remnant 1E0102.2-7219

We present Chandra X-ray Observatory archival observations of the supernova remnant 1E0102.2-7219, a young Oxygen-rich remnant in the Small Magellanic Cloud. Combining 28 ObsIDs for 324 ks of total exposure time, we present an ACIS image with an unprecedented signal-to-noise ratio (mean S/N ~ sqrt(S) ~6; maximum S/N > 35) . We search within the remnant, using the source detection software {\sc wavdetect}, for point sources which may indicate a compact object. Despite finding numerous detections of high significance in both broad and narrow band images of the remnant, we are unable to satisfactorily distinguish whether these detections correspond to emission from a compact object. We also present upper limits to the luminosity of an obscured compact stellar object which were derived from an analysis of spectra extracted from the high signal-to-noise image. We are able to further constrain the characteristics of a potential neutron star for this remnant with the results of the analysis presented here, though we cannot confirm the existence of such an object for this remnant.Comment: Accepted to the Astrophysical Journa

A Broadband X-Ray Study of the Supernova Remnant 3C 397

We present an X-ray study of the radio bright supernova remnant (SNR) 3C 397 with ROSAT, ASCA, and RXTE. A central X-ray spot seen with the ROSAT High-Resolution Imager hints at the presence of a pulsar-powered component, and gives this SNR a composite X-ray morphology. Combined ROSAT and ASCA imaging show that the remnant is highly asymmetric, with its hard X-ray emission peaking at the western lobe. The spectrum of 3C 397 is heavily absorbed, and dominated by thermal emission with emission lines evident from Mg, Si, S, Ar and Fe. Single-component models fail to describe the spectrum, and at least two components are required. We use a set of non-equilibrium ionization (NEI) models (Borkowski et al. in preparation). The temperatures from the soft and hard components are 0.2 keV and 1.6 keV respectively. The corresponding ionization time-scales $n_0 t$ ($n_0$ being the pre-shock hydrogen density) are 6 $\times 10^{12}$ cm$^{-3}$ s and 6 $\times$ 10$^{10}$ cm$^{-3}$ s, respectively. The spectrum obtained with the Proportional Counter Array (PCA) of RXTE is contaminated by emission from the Galactic ridge, with only $\sim$ 15% of the count rate originating from 3C 397 in the 5-15 keV range. The PCA spectrum allowed us to confirm the thermal nature of the hard X-ray emission. A third component originating from a pulsar-driven component is possible, but the contamination of the source signal by the Galactic ridge did not allow us to find pulsations from any hidden pulsar. We discuss the X-ray spectrum in the light of two scenarios: a young ejecta-dominated remnant of a core-collapse SN, and a middle-aged SNR expanding in a dense ISM. Spatially resolved spectroscopy (with CHANDRA and XMM) is needed to differentiate between the two scenarios, and address the nature of the mysterious radio-quiet X-ray hot spot.Comment: 21 pages including 8 figures and 5 tables. Accepted for publication in the Astrophysical journa

A Bow Shock Nebula Around a Compact X-Ray Source in the Supernova Remnant IC443

We present spectra and high resolution images of the hard X-ray feature along the southern edge of the supernova remnant IC443. Data from the Chandra X-ray Observatory reveal a comet-shaped nebula of hard emission, which contains a softer point source at its apex. We also present 20cm, 6cm, and 3.5cm images from the Very Large Array that clearly show the cometary nebula. Based on the radio and X-ray morphology and spectrum, and the radio polarization properties, we argue that this object is a synchrotron nebula powered by the compact source that is physically associated with IC443. The spectrum of the soft point source is adequately but not uniquely fit by a black body model (kT=0.71 +/- 0.08 keV, L=(6.5 +/- 0.9) * 10^31 erg/s). The cometary morphology of the nebula is the result of the supersonic motion of the neutron star (V_NS=250 +/- 50 km/s), which causes the relativistic wind of the pulsar to terminate in a bow shock and trail behind as a synchrotron tail. This velocity is consistent with an age of 30,000 years for the SNR and its associated neutron star.Comment: 9 pages, 5 figures, accepted for publication in the ApJ Letter

A Near-Infrared and X-ray Study of W49B: A Wind Cavity Explosion

We present near-infrared narrow-band images of the supernova remnant W49B, taken with the WIRC instrument on the Hale 200 inch telescope on Mt. Palomar. The 1.64 micron [Fe II] image reveals a barrel-shaped structure with coaxial rings, which is suggestive of bipolar wind structures surrounding massive stars. The 2.12 micron shocked molecular hydrogen image extends 1.9 pc outside of the [Fe II] emission to the southeast. We also present archival Chandra data, which show an X-ray jet-like structure along the axis of the [Fe II] barrel, and flaring at each end. Fitting single temperature X-ray emission models reveals: an enhancement of heavy elements, with particularly high abundances of hot Fe and Ni, and relatively metal-rich core and jet regions. We interpret these findings as evidence that W49B originated inside a wind-blown bubble (R ~ 5 pc) interior to a dense molecular cloud. This suggests that W49B's progenitor was a supermassive star, that could significantly shape its surrounding environment. We also suggest two interpretations for the jet morphology, abundance variations and molecular hydrogen emission: (1) the explosion may have been jet-driven and interacting with the molecular cavity (i.e. a Gamma-ray burst); or (2) the explosion could have been a traditional supernova, with the jet structure being the result of interactions between the shock and an enriched interstellar cloud.Comment: 9 pages with embedded figures Accepted by the Astrophysical Journa

How are secure attachment relationships fostered through talk between teachers and students who have been adopted? A conversation analysis

Despite the growing recognition of the importance of supportive teacher–student relationships to create safety for young people who have experienced early adversity and trauma, there is not a clear understanding of what factors make for positive school relationships and how these can be fostered. The aims of the study were to explore how children with challenging emotional backgrounds are supported by their key adult in school and how this occurs in the process of conversations between them. Three student–teacher pairs from a specialist school took part in a semi-structured interview about their relationship. Data was analysed using conversation analysis. Analysis found how teaching staff use several conversational markers in talk with children with attachment difficulties when emotional experiences are raised and when troubles occur in navigating difficult conversations. Recommendations for clinical practice and future research are made. </jats:p

Developing implementation research capacity: longitudinal evaluation of the King's College London Implementation Science Masterclass, 2014-2019.

BACKGROUND: Despite an increasing number of training opportunities in implementation science becoming available, the demand for training amongst researchers and practitioners is unmet. To address this training shortfall, we developed the King's College London 'Implementation Science Masterclass' (ISM), an innovative 2-day programme (and currently the largest of its kind in Europe), developed and delivered by an international faculty of implementation experts. METHODS: This paper describes the ISM and provides delegates' quantitative and qualitative evaluations (gathered through a survey at the end of the ISM) and faculty reflections over the period it has been running (2014-2019). RESULTS: Across the 6-year evaluation, a total of 501 delegates have attended the ISM, with numbers increasing yearly from 40 (in 2014) to 147 (in 2019). Delegates represent a diversity of backgrounds and 29 countries from across the world. The overall response rate for the delegate survey was 64.5% (323/501). Annually, the ISM has been rated 'highly' in terms of delegates' overall impression (92%), clear and relevant learning objectives (90% and 94%, respectively), the course duration (85%), pace (86%) and academic level 87%), and the support provided on the day (92%). Seventy-one percent of delegates reported the ISM would have an impact on how they approached their future work. Qualitative feedback revealed key strengths include the opportunities to meet with an international and diverse pool of experts and individuals working in the field, the interactive nature of the workshops and training sessions, and the breadth of topics and contexts covered. CONCLUSIONS: Yearly, the UK ISM has grown, both in size and in its international reach. Rated consistently favourably by delegates, the ISM helps to tackle current training demands from all those interested in learning and building their skills in implementation science. Evaluation of the ISM will continue to be an annual iterative process, reflective of changes in the evidence base and delegates changing needs as the field evolves