scholarly journals XMM-Newton observations of elliptical galaxies in the local universe

2009 ◽  
Vol 5 (H15) ◽  
pp. 273-273
Author(s):  
Ginevra Trinchieri
Keyword(s):  
Globular Clusters ◽  
Large Scale ◽  
Spectral Characteristics ◽  
Large Field ◽  
Specific Class ◽  
Early Type ◽  
X Ray ◽  
Compact Source ◽  
Wide Range ◽  
The Individual

XMM-Newton is well suited to the study of the X-ray properties of early-type galaxies: the wide energy band allows a characterization of the different components of the X-ray emission in galaxies, separating the gas from the compact source component through their spectral characteristics, and identifying low-luminosity absorbed AGNs; the large field of view allows a proper understanding of the large scale emission, and the separation between the galaxy and the surrounding group. Nonetheless, in spite of the much improved understanding of the X-ray characteristics of this class of sources, much of the original questions on the global X-ray properties of early-type galaxies remain. One in particular: how can we predict how much gas is there in any given galaxy? We have learned that the individual sources are tightly linked to the stellar component, both field stars and relative frequency of globular clusters. We have also learned that the central group galaxies, brighter and more extended, might represent a specific class of early-type galaxies, rather than the population as a whole. Yet we have not learned how to predict, from the stellar properties, how much hot gas a galaxy will have. Even a well selected class of sources, namely early type galaxies in isolation, where we can exclude the influence of the environment, appear to retain different amounts of the hot ISM produced by the stellar population, and display a wide range of Lx for their gaseous component for a relative narrow range of Lb, or mass [measured through LK], as shown by Fig. 1.

scholarly journals Shadow monochromatic backlighting: Large-field high resolution X-ray shadowgraphy with improved spectral tunability

2001 ◽  
Vol 19 (2) ◽  
pp. 285-293 ◽  
Author(s):  
T.A. PIKUZ ◽  
A. YA. FAENOV ◽  
M. FRAENKEL ◽  
A. ZIGLER ◽  
F. FLORA ◽  
...  
Keyword(s):  
High Resolution ◽  
High Spatial Resolution ◽  
Field Of View ◽  
Large Field ◽  
X Ray ◽  
Traditional Scheme ◽  
Wide Range ◽  
Wide Wavelength Range ◽  
Bent Crystals ◽  
First Time

The shadow monochromatic backlighting (SMB) scheme, a modification of the well-known soft X-ray monochromatic backlighting scheme, is proposed. It is based on a spherical crystal as the dispersive element and extends the traditional scheme by allowing one to work with a wide range of Bragg angles and thus in a wide spectral range. The advantages of the new scheme are demonstrated experimentally and supported numerically by ray-tracing simulations. In the experiments, the X-ray backlighter source is a laser-produced plasma, created by the interaction of an ultrashort pulse, Ti:Sapphire laser (120 fs, 3–5 mJ, 1016 W/cm2 on target) or a short wavelength XeCl laser (10 ns, 1–2 J, 1013 W/cm2 on target) with various solid targets (Dy, Ni + Cr, BaF2). In both experiments, the X-ray sources are well localized spatially (∼20 μm) and are spectrally tunable in a relatively wide wavelength range (λ = 8–15 Å). High quality monochromatic (δλ/λ ∼ 10−5–10−3) images with high spatial resolution (up to ∼4 μm) over a large field of view (a few square millimeters) were obtained. Utilization of spherically bent crystals to obtain high-resolution, large field, monochromatic images in a wide range of Bragg angles (35° < Θ < 90°) is demonstrated for the first time.

scholarly journals The Ghosts of Galaxies: Tidal Debris in Clusters

2004 ◽  
Vol 217 ◽  
pp. 70-76
Author(s):  
Michael D. Gregg ◽  
Michael J. West
Keyword(s):  
Globular Clusters ◽  
Surface Brightness ◽  
Large Scale ◽  
Dwarf Galaxies ◽  
Cluster Formation ◽  
X Ray ◽  
Cluster Evolution ◽  
Low Surface Brightness ◽  
Intergalactic Space ◽  
Formation And Evolution

Gravitational interactions in rich clusters can strip material from the outer parts of galaxies or even completely disrupt entire systems, giving rise to large scale, low surface brightness ghostly features stretching across intergalactic space. The nearby Coma and Centaurus clusters both have striking examples of galaxy ghosts, in the form of 100 kpc-long plumes of intergalactic debris. By searching HST archival images, we have found numerous other examples of galaxy ghosts in rich clusters at low redshift, evidence that galaxy destruction and recycling are ubiquitous, important in cluster formation and evolution, and continue to mold clusters at the present epoch. Many ghosts appear in X-ray bright clusters, perhaps signaling a connection with energetic subcluster mergers.The fate of such material has important ramifications for cluster evolution. Our new HST WFPC2 V & I images of a portion of the Centaurus plume reveal that it contains an excess of discrete objects with −12 < MV < −6, consistent with being globular clusters or smaller dwarf galaxies. This tidally liberated material is being recycled directly into the intracluster population of stars, dwarf galaxies, globular clusters, and gas, which may have been built largely from a multitude of similar events over the life of the cluster.

scholarly journals X-Ray Binaries in Early Type Galaxies and the Globular Cluster Connection

2004 ◽  
Vol 194 ◽  
pp. 73-74
Author(s):  
T. J. Maccarone ◽  
A Kundu ◽  
S. E. Zepf ◽  
T. H. Puzia
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Early Type ◽  
X Ray ◽  
X Ray Binaries ◽  
Cluster Age ◽  
Made In

AbstractWe summarize the key observations made in recent observations of X-ray sources in early-type galaxies. Typically about half of the X-ray binaries in early-type galaxies are in globular clusters, they are preferentially found in metal rich globular clusters, and there is no indication that cluster-age is an important parameter. Theoretical challenges are presented by these results.

scholarly journals Reflections on Analytical Choices in the Scaling Model for Test Scores in International Large-Scale Assessment Studies

2021 ◽  
Author(s):  
Alexander Robitzsch ◽  
Oliver Lüdtke
Keyword(s):  
Large Scale ◽  
International Student ◽  
Student Assessment ◽  
Individual Student ◽  
Scaling Model ◽  
Large Scale Assessment ◽  
International Student Assessment ◽  
Wide Range ◽  
Analytical Strategies ◽  
The Individual

International large-scale assessments (LSAs) such as the Programme for International Student Assessment (PISA) provide important information about the distribution of student proficiencies across a wide range of countries. The repeated assessments of these content domains offer policymakers important information for evaluating educational reforms and received considerable attention from the media. Furthermore, the analytical strategies employed in LSAs often define methodological standards for applied researchers in the field. Hence, it is vital to critically reflect the conceptual foundations of analytical choices in LSA studies. This article discusses methodological challenges in selecting and specifying the scaling model used to obtain proficiency estimates from the individual student responses in LSA studies. We distinguish design-based inference from model-based inference. It is argued that for the official reporting of LSA results, design-based inference should be preferred because it allows for a clear definition of the target of inference (e.g., country mean achievement) and is less sensitive to specific modeling assumptions. More specifically, we discuss five analytical choices in the specification of the scaling model: (1) Specification of the functional form of item response functions, (2) the treatment of local dependencies and multidimensionality, (3) the consideration of test-taking behavior for estimating student ability, and the role of country differential items functioning (DIF) for (4) cross-country comparisons, and (5) trend estimation. This article's primary goal is to stimulate discussion about recently implemented changes and suggested refinements of the scaling models in LSA studies.

scholarly journals Feasibility of Repeated Assessment of Cognitive Function in Older Adults Using a Wireless, Mobile, Dry-EEG Headset and Tablet-Based Games

2021 ◽  
Vol 12 ◽  
Author(s):  
Esther C. McWilliams ◽  
Florentine M. Barbey ◽  
John F. Dyer ◽  
Md Nurul Islam ◽  
Bernadette McGuinness ◽  
...  
Keyword(s):  
Large Scale ◽  
Age Groups ◽  
Therapy Response ◽  
Ease Of Use ◽  
Large Field ◽  
Age Related ◽  
System Usability Scale ◽  
Wide Range ◽  
Scale Scores ◽  
Mean Compliance

Access to affordable, objective and scalable biomarkers of brain function is needed to transform the healthcare burden of neuropsychiatric and neurodegenerative disease. Electroencephalography (EEG) recordings, both resting and in combination with targeted cognitive tasks, have demonstrated utility in tracking disease state and therapy response in a range of conditions from schizophrenia to Alzheimer's disease. But conventional methods of recording this data involve burdensome clinic visits, and behavioural tasks that are not effective in frequent repeated use. This paper aims to evaluate the technical and human-factors feasibility of gathering large-scale EEG using novel technology in the home environment with healthy adult users. In a large field study, 89 healthy adults aged 40–79 years volunteered to use the system at home for 12 weeks, 5 times/week, for 30 min/session. A 16-channel, dry-sensor, portable wireless headset recorded EEG while users played gamified cognitive and passive tasks through a tablet application, including tests of decision making, executive function and memory. Data was uploaded to cloud servers and remotely monitored via web-based dashboards. Seventy-eight participants completed the study, and high levels of adherence were maintained throughout across all age groups, with mean compliance over the 12-week period of 82% (4.1 sessions per week). Reported ease of use was also high with mean System Usability Scale scores of 78.7. Behavioural response measures (reaction time and accuracy) and EEG components elicited by gamified stimuli (P300, ERN, Pe and changes in power spectral density) were extracted from the data collected in home, across a wide range of ages, including older adult participants. Findings replicated well-known patterns of age-related change and demonstrated the feasibility of using low-burden, large-scale, longitudinal EEG measurement in community-based cohorts. This technology enables clinically relevant data to be recorded outside the lab/clinic, from which metrics underlying cognitive ageing could be extracted, opening the door to potential new ways of developing digital cognitive biomarkers for disorders affecting the brain.

The Russo-Turkish Wars in Russian Literature: Axiological Priorities in Historical Dynamics

2021 ◽  
Vol 80 (4) ◽  
pp. 5
Author(s):  
D. V. Larkovich
Keyword(s):  
Large Scale ◽  
Analytical Description ◽  
Direct Evaluation ◽  
Wide Range ◽  
Military Conflicts ◽  
Historical Dynamics ◽  
Russian Literary ◽  
Literary Process ◽  
Battle Scenes ◽  
The Individual

The paper represents the experience of analytical description of the fictional discourse, which captures the chronicle of the long-lasting military confrontation between the Russian Empire and the Sublime Porta. The author pursues the goal to trace the logic of evaluative dynamic specific to the Russian literary tradition in the perception and reflection of the events of the Russo-Turkish wars. The material of the paper is a sufficiently voluminous corpus of literary and journalistic texts, most fully and clearly representing the wide range and variability of axiological attitudes of participants of the XVI–XIX centuries national literary process who responded to these events. Among them are such iconic names for Russian intellectual and artistic culture as M.V. Lomonosov, G.R. Derzhavin, A.F. Veltman, A.A. Bestuzhev-Marlinsky, M.P. Pogodin, N.A. Nekrasov, A.N. Pleshcheev, L.N. Tolstoy, F.M. Dostoevsky, V.M. Garshin and many others. As a result, the author concludes that the nearly four-century history of the Russo-Turkish wars provided rich material for creative initiatives of Russian writers and significantly influenced the development of the Russian literary process. Reacting swiftly to the events of numerous military conflicts, fiction produced and clearly demonstrated ideological and axiological priorities of public consciousness from the perspective of their historical dynamics. The general logic of the Russian-Turkish confrontation theme development was directly expressed at the level of poetics in artistic creations. Comparing the early literary experiences of understanding and depicting military conflicts, one can observe a general movement from the general to the particular, from the collective to the individual, from direct evaluation to complex ethical collisions. As artistic consciousness develops, depictions of large-scale battle scenes give way to literary sketches of inner experiences, psychological and existential perspectives replace the external perspective of describing events. The perception of the war is gradually, but more distinctly reveals through the prism of the personal consciousness of an author and his character and is perceived as a personally lived meaningful experience.

Assembly Sites in Scandinavia: Activities and Rituals of the Community

2017 ◽  
Author(s):  
Alexandra Sanmark
Keyword(s):  
Social Cohesion ◽  
Large Scale ◽  
Group Interaction ◽  
Collective Memories ◽  
Community Activities ◽  
The People ◽  
Large Numbers ◽  
Wide Range ◽  
The Individual ◽  
Shared Ownership

Chapter 5 shifts the focus to the rituals and activities of the wider community in Scandinavia. At thing sites a wide range of community activities and rituals, which most likely and created collective memories and strengthened social cohesion, were enacted. Many of these activities may have been designed by the elite, but equally the idea of assemblies as communal spaces may have been collectively driven. The archaeological signature of meeting-places and assembly-sites suggests associations with feasting and eating on a large-scale, and architectural layouts that emphasised the collective over the individual and facilitated group interaction and cohesion. The construction, enlargement and maintenance of monuments and other features required the participation of large numbers of people. By joining in this work the population gained shared ownership of the sites. This was further enhanced by communal activities during the meetings, which also involved games and sports, as well as trade. Assemblies therefore formed arenas of interplay between the top-elite and the wider population; kings were elected and ruled through the assembly, while at the same time continuously dependent on the endorsement of the people.

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