Download or read book Optical SZE Scaling Relations for DES Optically Selected Clusters Within the SPT SZ Survey written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We study the Sunyaev-Zel'dovich effect (SZE) signature in South Pole Telescope (SPT) data for an ensemble of 719 optically identified galaxy clusters selected from 124.6 deg$^2$ of the Dark Energy Survey (DES) science verification data, detecting a stacked SZE signal down to richness $\lambda\sim20$. The SZE signature is measured using matched-filtered maps of the 2500 deg$^2$ SPT-SZ survey at the positions of the DES clusters, and the degeneracy between SZE observable and matched-filter size is broken by adopting as priors SZE and optical mass-observable relations that are either calibrated using SPT selected clusters or through the Arnaud et al. (2010, A10) X-ray analysis. We measure the SPT signal to noise $\zeta$-$\lambda$, relation and two integrated Compton-$y$ $Y_\textrm$-$\lambda$ relations for the DES-selected clusters and compare these to model expectations accounting for the SZE-optical center offset distribution. For clusters with $\lambda> 80$, the two SPT calibrated scaling relations are consistent with the measurements, while for the A10-calibrated relation the measured SZE signal is smaller by a factor of $0.61 \pm 0.12$ compared to the prediction. For clusters at $20
Download or read book Constraints on the Richness mass Relation and the Optical SZE Positional Offset Distribution for SZE selected Clusters written by and published by . This book was released on 2015 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Galaxy Cluster Integrated Comptonization and Mass Scaling Relations with the South Pole Telescope written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe a method for measuring the integrated Comptonization (Y (SZ)) of clusters of galaxies from measurements of the Sunyaev-Zel'dovich (SZ) effect in multiple frequency bands and use this method to characterize a sample of galaxy clusters detected in the South Pole Telescope (SPT) data. We use a Markov Chain Monte Carlo method to fit a [beta]-model source profile and integrate Y (SZ) within an angular aperture on the sky. In simulated observations of an SPT-like survey that include cosmic microwave background anisotropy, point sources, and atmospheric and instrumental noise at typical SPT-SZ survey levels, we show that we can accurately recover [beta]-model parameters for inputted clusters. We measure Y (SZ) for simulated semi-analytic clusters and find that Y (SZ) is most accurately determined in an angular aperture comparable to the SPT beam size. We demonstrate the utility of this method to measure Y (SZ) and to constrain mass scaling relations using X-ray mass estimates for a sample of 18 galaxy clusters from the SPT-SZ survey. Measuring Y (SZ) within a 0.'75 radius aperture, we find an intrinsic log-normal scatter of 21% ± 11% in Y (SZ) at a fixed mass. Measuring Y (SZ) within a 0.3 Mpc projected radius (equivalent to 0.'75 at the survey median redshift z = 0.6), we find a scatter of 26% ± 9%. Prior to this study, the SPT observable found to have the lowest scatter with mass was cluster detection significance. We demonstrate, from both simulations and SPT observed clusters that Y (SZ) measured within an aperture comparable to the SPT beam size is equivalent, in terms of scatter with cluster mass, to SPT cluster detection significance.
Download or read book The NOAO XCS Survey the Optical to X ray Scaling Relations of Galaxy Clusters written by Nicola Mehrtens and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Precision Cosmology with Galaxy Cluster Surveys written by Hao-Yi Wu and published by Stanford University. This book was released on 2011 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: The acceleration of the universe, which is often attributed to "dark energy, " has posed one of the main challenges to fundamental physics. Galaxy clusters provide one of the most sensitive probes of dark energy because their abundance reflects the growth rate of large-scale structure and the expansion rate of the universe. Several large galaxy cluster surveys will soon provide tremendous statistical power to constrain the properties of dark energy; however, the constraining power of these surveys will be determined by how well systematic errors are controlled. Of these systematic errors, the dominant one comes from inferring cluster masses using observable signals of clusters, the so-called "observable--mass distribution." This thesis focuses on extracting dark energy information from forthcoming large galaxy cluster surveys, including how we maximize the cosmological information, how we control important systematics, and how precisely we need to calibrate theoretical models. We study how multi-wavelength follow-up observations can improve cluster mass calibration in optical surveys. We also investigate the impact of theoretical uncertainties in calibrating the spatial distributions of galaxy clusters on dark energy constraints. In addition, we explore how the formation history of galaxy clusters impacts the self-calibration of cluster mass. In addition, we use N-body simulations to develop a new statistical sample of cluster-size halos in order to further understand the observable--mass distribution. We study the completeness of subhalos in our cluster sample by comparing them with the satellite galaxies in the Sloan Digital Sky Survey. We also study how subhalo selections impact the inferred correlation between formation time and optical mass tracers, including cluster richness and velocity dispersion.
Download or read book An Introduction to Modern Cosmology written by Andrew Liddle and published by John Wiley & Sons. This book was released on 2015-03-09 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Introduction to Modern Cosmology Third Edition is an accessible account of modern cosmological ideas. The Big Bang Cosmology is explored, looking at its observational successes in explaining the expansion of the Universe, the existence and properties of the cosmic microwave background, and the origin of light elements in the universe. Properties of the very early Universe are also covered, including the motivation for a rapid period of expansion known as cosmological inflation. The third edition brings this established undergraduate textbook up-to-date with the rapidly evolving observational situation. This fully revised edition of a bestseller takes an approach which is grounded in physics with a logical flow of chapters leading the reader from basic ideas of the expansion described by the Friedman equations to some of the more advanced ideas about the early universe. It also incorporates up-to-date results from the Planck mission, which imaged the anisotropies of the Cosmic Microwave Background radiation over the whole sky. The Advanced Topic sections present subjects with more detailed mathematical approaches to give greater depth to discussions. Student problems with hints for solving them and numerical answers are embedded in the chapters to facilitate the reader’s understanding and learning. Cosmology is now part of the core in many degree programs. This current, clear and concise introductory text is relevant to a wide range of astronomy programs worldwide and is essential reading for undergraduates and Masters students, as well as anyone starting research in cosmology. The accompanying website for this text, http://booksupport.wiley.com, provides additional material designed to enhance your learning, as well as errata within the text.
Download or read book Galaxies at High Redshift written by I. Pérez-Fournon and published by Cambridge University Press. This book was released on 2003-03-20 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents lectures of the XI Canary Islands Winter School of Astrophysics written by experts in the field.
Download or read book Connecting Quarks with the Cosmos written by National Research Council and published by National Academies Press. This book was released on 2003-03-12 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances made by physicists in understanding matter, space, and time and by astronomers in understanding the universe as a whole have closely intertwined the question being asked about the universe at its two extremesâ€"the very large and the very small. This report identifies 11 key questions that have a good chance to be answered in the next decade. It urges that a new research strategy be created that brings to bear the techniques of both astronomy and sub-atomic physics in a cross-disciplinary way to address these questions. The report presents seven recommendations to facilitate the necessary research and development coordination. These recommendations identify key priorities for future scientific projects critical for realizing these scientific opportunities.
Download or read book A Survey of Radial Velocities in the Zodiacal Dust Cloud written by Brian May and published by Springer Science & Business Media. This book was released on 2008-08-05 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the summer and autumn of 2006 I read several interviews with Brian May in which he mentioned his desire to complete the PhD that he had abandoned in 1974. I looked up the papers he had published while a PhD student, which were on spectroscopic studies of the motion of the dust responsible for the zodiacal light, and felt that there was a basis for a thesis. Since he had been a student at Imperial, I knew, as Head of the Astrophysics Group at Imperial, that it would be good for the Group if he came and worked with us. I got in touch with him by email and suggested he come and talk about it. He replied enthusiastically and said that he was working on typing up what he had completed by 1974. I gradually realized that I was the only staff member at Imperial who had previously worked on zodiacal dust, so that I would have to act as his supervisor. Eventually we met and I tried to assess whether he would be able to find time for the huge amount of work that finishing off a thesis involves, particularly if it has not been touched for over 30 years. Since some of Brian’s emails were coming from the recording studio I knew there was strong competition for his time.
Download or read book Cosmological Physics written by J. A. Peacock and published by Cambridge University Press. This book was released on 1999 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and authoritative introduction to contemporary cosmology for advanced undergraduate and graduate students.
Download or read book Very Low Mass Stars and Brown Dwarfs written by Rafael Rebolo and published by Cambridge University Press. This book was released on 2000-11-27 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a state-of-the-art review of our current knowledge of brown dwarfs and very low-mass stars. The hunt for and study of these elusive objects is currently one of the most dynamic areas of research in astronomy for two reasons. Brown dwarfs bridge the gap between stars and planets, and they may constitute an important part of the 'dark matter' of the Universe. This volume presents review articles from a team of international authorities who gathered at a conference in La Palma to assess the spectacular progress that has been made in this field in the last few years.
Download or read book The Physics of Space Security written by David Wright and published by . This book was released on 2005 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Urban Rail Development Handbook written by Daniel Pulido and published by World Bank Publications. This book was released on 2018-09-11 with total page 845 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cities across the globe are looking to develop affordable, environmentally friendly, and socially responsible transportation solutions that can meet the accessibility needs of expanding metropolitan populations and support future economic and urban development. When appropriately planned and properly implemented as part of a larger public transportation network, urban rail systems can provide rapid mobility and vital access to city centers from surrounding districts. High-performing urban rail services, when carefully approached as development projects, can help enhance quality of life by giving citizens access to employment opportunities, essential services, urban amenities, and neighboring communities. The purpose of this Handbook is to synthesize and disseminate knowledge to inform the planning, implementation, and operations of urban rail projects with a view towards: -- Emphasizing the need for early studies and project planning; -- Making projects more sustainable (economically, socially, and environmentally); -- Improving socioeconomic returns and access to opportunities for users; -- Maximizing the value of private participation, where appropriate; and -- Building capacity within project implementing and managing institutions This Handbook provides experiential advice to tackle the technical, institutional, and financial challenges faced by decision makers considering urban rail projects. It brings together the expertise of World Bank staff and the input of numerous specialists to synthesize international 'good practices' and recommendations that are independent of commercial, financial political, or other interests. The material presented is intended as an honest-broker guide to maximize the impact and manage the challenges of urban rail systems in cities in both developed and developing countries. Rather than identify a single approach, this Handbook acknowledges the complexities and context necessary when approaching an urban rail development by helping to prepare decision makers to ask the right questions, consider the key issues, perform the necessary studies, apply adequate tools, and learn from international good practice all at the right time in the project development process.
Download or read book Software Defined Radio for Engineers written by Alexander M. Wyglinski and published by Artech House. This book was released on 2018-04-30 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on the popular Artech House classic, Digital Communication Systems Engineering with Software-Defined Radio, this book provides a practical approach to quickly learning the software-defined radio (SDR) concepts needed for work in the field. This up-to-date volume guides readers on how to quickly prototype wireless designs using SDR for real-world testing and experimentation. This book explores advanced wireless communication techniques such as OFDM, LTE, WLA, and hardware targeting. Readers will gain an understanding of the core concepts behind wireless hardware, such as the radio frequency front-end, analog-to-digital and digital-to-analog converters, as well as various processing technologies. Moreover, this volume includes chapters on timing estimation, matched filtering, frame synchronization message decoding, and source coding. The orthogonal frequency division multiplexing is explained and details about HDL code generation and deployment are provided. The book concludes with coverage of the WLAN toolbox with OFDM beacon reception and the LTE toolbox with downlink reception. Multiple case studies are provided throughout the book. Both MATLAB and Simulink source code are included to assist readers with their projects in the field.
Download or read book Pathways to Discovery in Astronomy and Astrophysics for the 2020s written by National Academies of Sciences, Engineering, and Medicine and published by . This book was released on 2022-08-04 with total page 615 pages. Available in PDF, EPUB and Kindle. Book excerpt: The steering committee was specifically asked to (1) provide an overview of the current state of astronomy and astrophysics science, and technology research in support of that science, with connections to other scientific areas where appropriate; (2) identify the most compelling science challenges and frontiers in astronomy and astrophysics, which shall motivate the committee’s strategy for the future; (3) develop a comprehensive research strategy to advance the frontiers of astronomy and astrophysics for the period 2022-2032 that will include identifying, recommending, and ranking the highest-priority research activities; (4) utilize and recommend decision rules, where appropriate, that can accommodate significant but reasonable deviations in the projected budget or changes in urgency precipitated by new discoveries or unanticipated competitive activities; (5) assess the state of the profession, including workforce and demographic issues in the field, identify areas of concern and importance to the community, and where possible, provide specific, actionable, and practical recommendations to the agencies and community to address these areas. This report proposes a broad, integrated plan for space- and ground-based astronomy and astrophysics for the decade 2023-2032. It also lays the foundations for further advances in the following decade.
Download or read book IBM Power Systems SR IOV Technical Overview and Introduction written by Scott Vetter and published by IBM Redbooks. This book was released on 2017-01-12 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: This IBM® RedpaperTM publication describes the adapter-based virtualization capabilities that are being deployed in high-end IBM POWER7+TM processor-based servers. Peripheral Component Interconnect Express (PCIe) single root I/O virtualization (SR-IOV) is a virtualization technology on IBM Power Systems servers. SR-IOV allows multiple logical partitions (LPARs) to share a PCIe adapter with little or no run time involvement of a hypervisor or other virtualization intermediary. SR-IOV does not replace the existing virtualization capabilities that are offered as part of the IBM PowerVM® offerings. Rather, SR-IOV compliments them with additional capabilities. This paper describes many aspects of the SR-IOV technology, including: A comparison of SR-IOV with standard virtualization technology Overall benefits of SR-IOV Architectural overview of SR-IOV Planning requirements SR-IOV deployment models that use standard I/O virtualization Configuring the adapter for dedicated or shared modes Tips for maintaining and troubleshooting your system Scenarios for configuring your system This paper is directed to clients, IBM Business Partners, and system administrators who are involved with planning, deploying, configuring, and maintaining key virtualization technologies.
Download or read book IBM Power 520 Technical Overview written by Scott Vetter and published by IBM Redbooks. This book was released on 2010-04-02 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: This IBM Redpaper publication is a comprehensive guide covering the IBM Power 520 server, machine type model 8203-E4A. The goal of this paper is to introduce this innovative server that includes IBM System i and IBM System p and new hardware technologies. The major hardware offerings include: - The POWER6 processor, available at frequencies of 4.2 GHz and 4.7 GHz. - Specialized POWER6 DDR2 memory that provides greater bandwidth, capacity, and reliability. - The 1 Gb or 10 Gb Integrated Virtual Ethernet adapter that brings native hardware virtualization to this server. - EnergyScale technology that provides features such as power trending, power-saving, capping of power, and thermal measurement. - PowerVM virtualization technology. - Mainframe continuous availability brought to the entry server environment. This Redpaper expands the current set of IBM Power System documentation by providing a desktop reference that offers a detailed technical description of the Power 520 system. This Redpaper does not replace the latest marketing materials and tools. It is intended as an additional source of information that, together with existing sources, can be used to enhance your knowledge of IBM server solutions.
